Trial Outcomes & Findings for Study of Tecovirimat for Human Mpox Virus (NCT NCT05534984)

NCT ID: NCT05534984

Last Updated: 2026-02-10

Results Overview

Clinical resolution defined as all skin lesions scabbed, desquamated, or healed, and visible mucosal lesions healed. The cumulative incidence of clinical resolution was estimated using the Aalen-Johansen estimator. The treatment effect, i.e., the subdistribution hazard ratio of tecovirimat relative to placebo, was estimated using the Fine and Gray subdistribution proportional hazards model. All-cause death, start of open-label tecovirimat due to disease progression or severe pain, and use of other antivirals with expected activity against mpox were treated as competing events. Follow-up time was censored at last contact. Includes data from follow-up visits occurring through October 23, 2024.

• Recruitment status: TERMINATED
• Study phase: PHASE3
• Target enrollment: 719 participants
• Primary outcome timeframe: From study entry through 28 days of follow-up (i.e., Day 29)
• Results posted on: 2026-02-10

Participant Flow

Participants were enrolled at 58 clinical research sites in 7 countries (United States, Peru, Mexico, Thailand, Argentina, Japan, and Brazil) from September 2022 to November 2024.

Participant milestones

Measure	Tecovirimat (Arm A) Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Overall Study STARTED	290	148	281
Overall Study Started Treatment	290	146	281
Overall Study Started Open-Label Tecovirimat	23	13	281
Overall Study COMPLETED	231	112	233
Overall Study NOT COMPLETED	59	36	48

Reasons for withdrawal

Measure	Tecovirimat (Arm A) Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Overall Study Negative for HMPXV	30	21	20
Overall Study Lost to Follow-up	23	11	26
Overall Study Withdrawal by Subject	6	3	2
Overall Study Adverse Event	0	1	0

Baseline Characteristics

Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.

Baseline characteristics by cohort

Measure	Tecovirimat (Arm A) n=290 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=147 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=281 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Total n=718 Participants Total of all reporting groups
Age, Continuous	34 years n=290 Participants	34 years n=147 Participants	35 years n=281 Participants	34 years n=718 Participants
Age, Customized <40 years	214 Participants n=290 Participants	103 Participants n=147 Participants	194 Participants n=281 Participants	511 Participants n=718 Participants
Age, Customized >=40 years	76 Participants n=290 Participants	44 Participants n=147 Participants	87 Participants n=281 Participants	207 Participants n=718 Participants
Sex/Gender, Customized Cisgender	284 Participants n=290 Participants	141 Participants n=147 Participants	269 Participants n=281 Participants	694 Participants n=718 Participants
Sex/Gender, Customized Transgender spectrum	6 Participants n=290 Participants	6 Participants n=147 Participants	12 Participants n=281 Participants	24 Participants n=718 Participants
Sex: Female, Male Female	4 Participants n=290 Participants	5 Participants n=147 Participants	12 Participants n=281 Participants	21 Participants n=718 Participants
Sex: Female, Male Male	286 Participants n=290 Participants	142 Participants n=147 Participants	269 Participants n=281 Participants	697 Participants n=718 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	137 Participants n=290 Participants	60 Participants n=147 Participants	133 Participants n=281 Participants	330 Participants n=718 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	150 Participants n=290 Participants	82 Participants n=147 Participants	143 Participants n=281 Participants	375 Participants n=718 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	3 Participants n=290 Participants	5 Participants n=147 Participants	5 Participants n=281 Participants	13 Participants n=718 Participants
Race/Ethnicity, Customized White	149 Participants n=290 Participants	86 Participants n=147 Participants	150 Participants n=281 Participants	385 Participants n=718 Participants
Race/Ethnicity, Customized Black or African American	35 Participants n=290 Participants	11 Participants n=147 Participants	69 Participants n=281 Participants	115 Participants n=718 Participants
Race/Ethnicity, Customized Asian	19 Participants n=290 Participants	16 Participants n=147 Participants	12 Participants n=281 Participants	47 Participants n=718 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	2 Participants n=290 Participants	0 Participants n=147 Participants	1 Participants n=281 Participants	3 Participants n=718 Participants
Race/Ethnicity, Customized American Indian or Alaska Native	3 Participants n=290 Participants	0 Participants n=147 Participants	1 Participants n=281 Participants	4 Participants n=718 Participants
Race/Ethnicity, Customized Other	28 Participants n=290 Participants	11 Participants n=147 Participants	15 Participants n=281 Participants	54 Participants n=718 Participants
Race/Ethnicity, Customized Multiple	6 Participants n=290 Participants	3 Participants n=147 Participants	7 Participants n=281 Participants	16 Participants n=718 Participants
Race/Ethnicity, Customized Unknown	48 Participants n=290 Participants	20 Participants n=147 Participants	26 Participants n=281 Participants	94 Participants n=718 Participants
Region of Enrollment Argentina	3 Participants n=290 Participants	2 Participants n=147 Participants	3 Participants n=281 Participants	8 Participants n=718 Participants
Region of Enrollment United States	234 Participants n=290 Participants	120 Participants n=147 Participants	241 Participants n=281 Participants	595 Participants n=718 Participants
Region of Enrollment Japan	1 Participants n=290 Participants	1 Participants n=147 Participants	2 Participants n=281 Participants	4 Participants n=718 Participants
Region of Enrollment Brazil	1 Participants n=290 Participants	0 Participants n=147 Participants	13 Participants n=281 Participants	14 Participants n=718 Participants
Region of Enrollment Mexico	13 Participants n=290 Participants	7 Participants n=147 Participants	8 Participants n=281 Participants	28 Participants n=718 Participants
Region of Enrollment Thailand	10 Participants n=290 Participants	4 Participants n=147 Participants	7 Participants n=281 Participants	21 Participants n=718 Participants
Region of Enrollment Peru	28 Participants n=290 Participants	13 Participants n=147 Participants	7 Participants n=281 Participants	48 Participants n=718 Participants
Days from Symptom Onset, Continuous	7 days n=290 Participants	8 days n=147 Participants	8 days n=281 Participants	8 days n=718 Participants
Days from Symptom Onset, Categorical <=5 days	76 Participants n=290 Participants	40 Participants n=147 Participants	69 Participants n=281 Participants	185 Participants n=718 Participants
Days from Symptom Onset, Categorical >5 days	214 Participants n=290 Participants	107 Participants n=147 Participants	212 Participants n=281 Participants	533 Participants n=718 Participants
Pain Level, Continuous	5 score on a scale n=290 Participants	5 score on a scale n=147 Participants	6 score on a scale n=281 Participants	6 score on a scale n=718 Participants
Pain Level, Categorical Mild (0-3)	107 Participants n=290 Participants	46 Participants n=147 Participants	60 Participants n=281 Participants	213 Participants n=718 Participants
Pain Level, Categorical Moderate (4-6)	77 Participants n=290 Participants	56 Participants n=147 Participants	85 Participants n=281 Participants	218 Participants n=718 Participants
Pain Level, Categorical Severe (7-10)	106 Participants n=290 Participants	45 Participants n=147 Participants	136 Participants n=281 Participants	287 Participants n=718 Participants
Number of Lesions, Continuous	10 lesions n=290 Participants	8 lesions n=147 Participants	30 lesions n=281 Participants	14 lesions n=718 Participants
Number of Lesions, Categorical <10	145 Participants n=290 Participants	82 Participants n=147 Participants	43 Participants n=281 Participants	270 Participants n=718 Participants
Number of Lesions, Categorical 10-100	139 Participants n=290 Participants	64 Participants n=147 Participants	197 Participants n=281 Participants	400 Participants n=718 Participants
Number of Lesions, Categorical >100	6 Participants n=290 Participants	1 Participants n=147 Participants	41 Participants n=281 Participants	48 Participants n=718 Participants
Proctitis Yes	102 Participants n=290 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.	46 Participants n=147 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.	111 Participants n=280 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.	259 Participants n=717 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.
Proctitis No	188 Participants n=290 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.	101 Participants n=147 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.	169 Participants n=280 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.	458 Participants n=717 Participants • Data missing for one participant assigned to the open-label tecovirimat arm because site did not perform the evaluation.
Receipt of >=1 Dose of Smallpox/Mpox Vaccine Yes	72 Participants n=290 Participants	36 Participants n=147 Participants	29 Participants n=281 Participants	137 Participants n=718 Participants
Receipt of >=1 Dose of Smallpox/Mpox Vaccine No	218 Participants n=290 Participants	111 Participants n=147 Participants	252 Participants n=281 Participants	581 Participants n=718 Participants
HIV Status Living with HIV	103 Participants n=289 Participants • HIV status missing for one participant randomized to tecovirimat.	42 Participants n=147 Participants • HIV status missing for one participant randomized to tecovirimat.	134 Participants n=281 Participants • HIV status missing for one participant randomized to tecovirimat.	279 Participants n=717 Participants • HIV status missing for one participant randomized to tecovirimat.
HIV Status Not living with HIV	182 Participants n=289 Participants • HIV status missing for one participant randomized to tecovirimat.	100 Participants n=147 Participants • HIV status missing for one participant randomized to tecovirimat.	137 Participants n=281 Participants • HIV status missing for one participant randomized to tecovirimat.	419 Participants n=717 Participants • HIV status missing for one participant randomized to tecovirimat.
HIV Status Probably living with HIV, based on best available information	0 Participants n=289 Participants • HIV status missing for one participant randomized to tecovirimat.	1 Participants n=147 Participants • HIV status missing for one participant randomized to tecovirimat.	1 Participants n=281 Participants • HIV status missing for one participant randomized to tecovirimat.	2 Participants n=717 Participants • HIV status missing for one participant randomized to tecovirimat.
HIV Status Probably not living with HIV, based on best available information	4 Participants n=289 Participants • HIV status missing for one participant randomized to tecovirimat.	3 Participants n=147 Participants • HIV status missing for one participant randomized to tecovirimat.	6 Participants n=281 Participants • HIV status missing for one participant randomized to tecovirimat.	13 Participants n=717 Participants • HIV status missing for one participant randomized to tecovirimat.
HIV Status No test results available	0 Participants n=289 Participants • HIV status missing for one participant randomized to tecovirimat.	1 Participants n=147 Participants • HIV status missing for one participant randomized to tecovirimat.	3 Participants n=281 Participants • HIV status missing for one participant randomized to tecovirimat.	4 Participants n=717 Participants • HIV status missing for one participant randomized to tecovirimat.
Pregnant Yes	0 Participants n=290 Participants	0 Participants n=147 Participants	1 Participants n=281 Participants	1 Participants n=718 Participants
Pregnant No	290 Participants n=290 Participants	147 Participants n=147 Participants	280 Participants n=281 Participants	717 Participants n=718 Participants
Breastfeeding Yes	0 Participants n=290 Participants	0 Participants n=147 Participants	0 Participants n=281 Participants	0 Participants n=718 Participants
Breastfeeding No	290 Participants n=290 Participants	147 Participants n=147 Participants	281 Participants n=281 Participants	718 Participants n=718 Participants
Prior Receipt of Tecovirimat Yes	0 Participants n=290 Participants	0 Participants n=147 Participants	0 Participants n=281 Participants	0 Participants n=718 Participants
Prior Receipt of Tecovirimat No	290 Participants n=290 Participants	147 Participants n=147 Participants	281 Participants n=281 Participants	718 Participants n=718 Participants

PRIMARY outcome

Timeframe: From study entry through 28 days of follow-up (i.e., Day 29)

Population: Eligible participants with laboratory-confirmed mpox and one or more skin or visible mucosal lesions that were able to be followed to resolution according to assigned treatment arm.

Clinical resolution defined as all skin lesions scabbed, desquamated, or healed, and visible mucosal lesions healed. The cumulative incidence of clinical resolution was estimated using the Aalen-Johansen estimator. The treatment effect, i.e., the subdistribution hazard ratio of tecovirimat relative to placebo, was estimated using the Fine and Gray subdistribution proportional hazards model. All-cause death, start of open-label tecovirimat due to disease progression or severe pain, and use of other antivirals with expected activity against mpox were treated as competing events. Follow-up time was censored at last contact. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=225 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=111 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=227 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Cumulative Proportion With Clinical Resolution by Day 29	0.83 cumulative proportion of participants Interval 0.77 to 0.87	0.84 cumulative proportion of participants Interval 0.76 to 0.9	0.85 cumulative proportion of participants Interval 0.79 to 0.9

SECONDARY outcome

Timeframe: Through 5 days of treatment (i.e., Treatment Day 6)

Population: Eligible participants with laboratory-confirmed mpox and severe pain (NRS 7-10) at baseline according to assigned treatment arm.

Pain was measured on 11-point numerical rating scale (NRS) where 0 = no pain and 10 = worst possible pain.

Pain intensity difference at ith day of treatment (i = 2, ..., 6) calculated as NRS pain score at baseline (last available pre-treatment) minus NRS pain score on ith day of treatment

Time-weighted average of pain intensity difference over 5 days of treatment was a weighted average of the pain intensity difference from treatment day 2 to treatment day 6, where the weights were calculated as the duration in days between the ith day of treatment and the day of the previous measurement. The lowest possible value that this could have been was -10, which would have indicated an increase in pain by 10 points on average over 5 days of treatment. The highest possible value that this could have been was +10, which would have indicated a decrease in pain by 10 points on average over 5 days of treatment.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=71 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=30 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=96 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Mean Time-weighted Average of Pain Intensity Difference Over 5 Days of Treatment	3.2 score on a scale Standard Deviation 2.1	3.1 score on a scale Standard Deviation 2.0	3.6 score on a scale Standard Deviation 2.1

SECONDARY outcome

Timeframe: Through 14 days of treatment (i.e., Treatment Day 15)

Population: Eligible participants with laboratory-confirmed mpox and severe pain (NRS 7-10) at baseline according to assigned treatment arm.

Pain was measured on 11-point numerical rating scale (NRS) where 0 = no pain and 10 = worst possible pain.

Pain intensity difference at ith day of treatment (i = 2, ..., 15) calculated as NRS pain score at baseline (last available pre-treatment) minus NRS pain score on ith day of treatment

Time-weighted average of pain intensity difference over 14 days of treatment was a weighted average of the pain intensity difference from treatment day 2 to treatment day 15, where the weights were calculated as the duration in days between the ith day of treatment and the day of the previous measurement. The lowest possible value that this could have been was -10, which would have indicated an increase in pain by 10 points on average over 5 days of treatment. The highest possible value that this could have been was +10, which would have indicated a decrease in pain by 10 points on average over 5 days of treatment.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=72 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=31 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=100 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Mean Time-weighted Average of Pain Intensity Difference Over 14 Days of Treatment	4.8 score on a scale Standard Deviation 2.2	4.9 score on a scale Standard Deviation 2.1	5.5 score on a scale Standard Deviation 2.0

SECONDARY outcome

Timeframe: From study entry through 56 days of follow-up (i.e., Day 57)

Population: Eligible participants with laboratory-confirmed mpox who did not have severe HMPXV disease at baseline according to assigned treatment arm. Participants who had severe HMPXV disease at baseline were enrolled into Arm C.

Severe HMPXV disease was defined as one or more of the following conditions: suspected or confirmed ocular involvement, facial lesions on the malar, nose, or eyelid region, confluent facial lesions, hospitalization due to HMPXV infection or its complications, or lesions that required surgical intervention including debridement, urinary catheterization, or sigmoidoscopy, or extended below the dermis.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=22 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Developed Severe HMPXV Disease	9 Participants	6 Participants	1 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, 22, 29, and 57

Population: Eligible participants enrolled in-person with laboratory-confirmed mpox according to assigned treatment arm.

HMPXV DNA was measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=179 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=84 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=191 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions Day 22	110 Participants	59 Participants	105 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions Day 29	112 Participants	64 Participants	102 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions Day 57	115 Participants	60 Participants	92 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions Baseline	18 Participants	12 Participants	23 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions Day 8	68 Participants	26 Participants	66 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Skin Lesions Day 15	106 Participants	53 Participants	122 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, 22, 29, and 57

Population: Eligible participants enrolled in-person with laboratory-confirmed mpox according to assigned treatment arm.

HMPXV DNA was measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=179 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=84 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=191 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx Baseline	85 Participants	45 Participants	48 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx Day 29	123 Participants	64 Participants	107 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx Day 8	137 Participants	67 Participants	140 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx Day 15	132 Participants	68 Participants	142 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx Day 22	121 Participants	63 Participants	115 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Oropharynx Day 57	120 Participants	61 Participants	95 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, 22, 29, and 57

Population: Eligible participants enrolled in-person with laboratory-confirmed mpox according to assigned treatment arm.

HMPXV DNA was measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=179 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=84 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=191 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants With HMPXV DNA Below Limit of Detection in Rectum Day 15	134 Participants	64 Participants	120 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Rectum Day 22	124 Participants	63 Participants	103 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Rectum Day 29	123 Participants	65 Participants	103 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Rectum Day 57	120 Participants	60 Participants	88 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Rectum Baseline	46 Participants	26 Participants	39 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Rectum Day 8	108 Participants	48 Participants	91 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, 22, 29, and 57

Population: Eligible participants enrolled in-person with laboratory-confirmed mpox according to assigned treatment arm.

HMPXV DNA measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=179 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=84 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=191 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants With HMPXV DNA Below Limit of Detection in Blood Baseline	69 Participants	45 Participants	40 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Blood Day 8	139 Participants	65 Participants	127 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Blood Day 15	136 Participants	65 Participants	133 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Blood Day 22	122 Participants	62 Participants	106 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Blood Day 29	125 Participants	67 Participants	105 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Blood Day 57	118 Participants	62 Participants	99 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, 22, 29, and 57

Population: Female participants enrolled in-person with laboratory-confirmed mpox according to assigned treatment arm.

HMPXV DNA measured as detected or below limit of detection. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=4 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=1 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=7 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs Baseline	0 Participants	0 Participants	1 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs Day 8	1 Participants	0 Participants	2 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs Day 15	1 Participants	0 Participants	2 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs Day 22	3 Participants	1 Participants	3 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs Day 29	4 Participants	1 Participants	3 Participants
Number of Participants With HMPXV DNA Below Limit of Detection in Vaginal Swabs Day 57	3 Participants	1 Participants	2 Participants

SECONDARY outcome

Timeframe: From study entry through 28 days of follow-up (i.e., Day 29)

Population: Eligible participants with laboratory-confirmed mpox and one or more skin or visible mucosal lesions that were able to be followed to resolution according to assigned treatment arm.

Complete lesion healing was defined as all lesions re-epithelialized. The cumulative incidence of complete lesion healing was estimated using the Aalen-Johansen estimator. The treatment effect, i.e., the subdistribution hazard ratio of tecovirimat relative to placebo, was estimated using the Fine and Gray subdistribution proportional hazards model. All-cause death, start of open-label tecovirimat due to disease progression or severe pain, and use of other antivirals with expected activity against mpox were treated as competing events. Follow-up time was censored at last contact. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=225 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=111 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=227 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Cumulative Proportion With Complete Lesion Healing by Day 29	0.75 cumulative proportion of participants Interval 0.68 to 0.8	0.75 cumulative proportion of participants Interval 0.66 to 0.83	0.69 cumulative proportion of participants Interval 0.62 to 0.75

SECONDARY outcome

Timeframe: Days 8 and 15

Population: Eligible participants who took at least one dose of tecovirimat or placebo according to assigned treatment arm.

Since the adherence assessment was removed from protocol version 3.0, the number of participants with adherence data was expected to be small and no formal statistical comparison between treatment arms was done. Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=275 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=136 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=266 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 15 · 0 missed doses	36 Participants	16 Participants	24 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 8 · 0 missed doses	43 Participants	18 Participants	27 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 8 · 3 missed doses	1 Participants	1 Participants	0 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 8 · 1 missed doses	0 Participants	0 Participants	1 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 8 · 2 missed doses	1 Participants	2 Participants	0 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 15 · 1 missed doses	1 Participants	1 Participants	2 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 15 · 2 missed doses	0 Participants	0 Participants	1 Participants
Number of Participants With no Missed Doses (of Last Three Prescribed Doses) Day 15 · 3 missed doses	0 Participants	0 Participants	0 Participants

SECONDARY outcome

Timeframe: Days 8, 15, and 29

Population: Eligible participants with laboratory-confirmed mpox according to assigned treatment arm.

Participants' self-rated health measured on a visual analogue scale (VAS) where 0 = "The worst health you can imagine" and 100 = "The best health you can imagine." Change in EQ VAS score at each timepoint calculated as absolute change from baseline (last available pre-treatment). Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=239 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Median Change From Baseline in EuroQol (EQ) Visual Analogue Scale (VAS) Score Day 29	20 score on a scale Interval 10.0 to 35.0	24.5 score on a scale Interval 10.0 to 30.0	25 score on a scale Interval 10.0 to 45.0
Median Change From Baseline in EuroQol (EQ) Visual Analogue Scale (VAS) Score Day 15	20 score on a scale Interval 5.0 to 35.0	20 score on a scale Interval 10.0 to 30.0	25 score on a scale Interval 10.0 to 40.0
Median Change From Baseline in EuroQol (EQ) Visual Analogue Scale (VAS) Score Day 8	10 score on a scale Interval 0.0 to 20.0	10 score on a scale Interval 5.0 to 25.0	15 score on a scale Interval 5.0 to 30.0

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, and 29

Population: Eligible participants with laboratory-confirmed mpox according to assigned treatment arm.

Participants' self-reported health state within mobility dimension of the five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=239 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · No problems	169 Participants	86 Participants	153 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · Any problems	58 Participants	28 Participants	71 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · No problems	197 Participants	98 Participants	180 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · Any problems	21 Participants	8 Participants	39 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · No problems	184 Participants	96 Participants	188 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · Any problems	6 Participants	1 Participants	14 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · No problems	170 Participants	83 Participants	176 Participants
Number of Participants Who Reported Each Level of Response on Mobility Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · Any problems	8 Participants	2 Participants	15 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, and 29

Population: Eligible participants with laboratory-confirmed mpox according to assigned treatment arm.

Participants' self-reported health state within self-care dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=239 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · Any problems	49 Participants	28 Participants	54 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · No problems	177 Participants	86 Participants	170 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · No problems	203 Participants	99 Participants	195 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · Any problems	15 Participants	7 Participants	24 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · No problems	184 Participants	94 Participants	186 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · Any problems	6 Participants	3 Participants	16 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · No problems	174 Participants	83 Participants	185 Participants
Number of Participants Who Reported Each Level of Response on Self-Care Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · Any problems	4 Participants	2 Participants	6 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, and 29

Population: Eligible participants with laboratory-confirmed mpox according to assigned treatment arm.

Participants' self-reported health state within usual activities dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=239 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · No problems	140 Participants	72 Participants	123 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · Any problems	87 Participants	42 Participants	101 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · No problems	171 Participants	88 Participants	164 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · Any problems	47 Participants	18 Participants	55 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · No problems	179 Participants	93 Participants	176 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · Any problems	11 Participants	4 Participants	26 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · No problems	172 Participants	82 Participants	171 Participants
Number of Participants Who Reported Each Level of Response on Usual Activities Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · Any problems	6 Participants	3 Participants	20 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, and 29

Population: Eligible participants with laboratory-confirmed mpox according to assigned treatment arm.

Participants' self-reported health state within pain/discomfort dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=239 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · No problems	158 Participants	80 Participants	157 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · Any problems	20 Participants	5 Participants	34 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · No problems	41 Participants	15 Participants	23 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · Any problems	186 Participants	99 Participants	201 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · No problems	119 Participants	59 Participants	98 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · Any problems	99 Participants	47 Participants	121 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · No problems	152 Participants	81 Participants	148 Participants
Number of Participants Who Reported Each Level of Response on Pain/Discomfort Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · Any problems	38 Participants	16 Participants	54 Participants

SECONDARY outcome

Timeframe: Baseline, Days 8, 15, and 29

Population: Eligible participants with laboratory-confirmed mpox according to assigned treatment arm.

Participants' self-reported health state within anxiety/depression dimension of five-dimension EuroQol EQ-5D-5L questionnaire. Participants were asked to indicate their health state by selecting the most appropriate response level for them from five ordinal response levels: no problems (1), slight problems (2), moderate problems (3), severe problems (4), and extreme problems (5).

Results were dichotomized into no problems (level 1) and any problems (levels 2, 3, 4, and 5 combined) for reporting and analysis.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=241 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=118 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=239 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · Any problems	40 Participants	20 Participants	64 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · Any problems	97 Participants	47 Participants	105 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · No problems	123 Participants	70 Participants	119 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Day 15 · Any problems	67 Participants	27 Participants	83 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · No problems	78 Participants	50 Participants	63 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Baseline · Any problems	149 Participants	64 Participants	161 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Day 8 · No problems	121 Participants	59 Participants	114 Participants
Number of Participants Who Reported Each Level of Response on Anxiety/Depression Dimension of EuroQol EQ-5D-5L Questionnaire Day 29 · No problems	138 Participants	65 Participants	127 Participants

SECONDARY outcome

Timeframe: Through 56 days of follow-up (i.e., Day 57)

Population: Eligible participants who took at least one dose of tecovirimat or placebo according to initial treatment received. Participants enrolled after October 23, 2024 were excluded.

Study protocol required reporting of all adverse events (AEs) that (1) led to a change in study treatment regardless of grade, (2) met the serious AE (SAE) or Expedited AE (EAE) reporting requirement, and (3) were Grade 3 or greater. AEs were graded using the DAIDS AE Grading Table (Version 2.1).

Severity Grade: 1 = Mild, 2 = Moderate, 3 = Severe, 4 = Life-Threatening, 5 = Death

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=275 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=136 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=266 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Proportion of Participants With Grade 3 or Greater Treatment-emergent Adverse Event	0.044 proportion of participants Interval 0.019 to 0.068	0.044 proportion of participants Interval 0.01 to 0.079	0.071 proportion of participants Interval 0.04 to 0.102

SECONDARY outcome

Timeframe: Through 56 days of follow-up (i.e., Day 57)

Population: Eligible participants according to assigned treatment arm. Participants enrolled after October 23, 2024 were excluded.

Includes data from follow-up visits occurring through October 23, 2024.

Outcome measures

Measure	Tecovirimat (Arm A) n=275 Participants Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) n=137 Participants Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Open-Label Tecovirimat (Arm C) n=266 Participants Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Number of Participants Who Died From Any Cause	0 Participants	0 Participants	0 Participants

SECONDARY outcome

Timeframe: On Day 8, blood samples were collected pre-dose and at 1, 2, 3, 4, 6, 8, and 10 hours post-dose. On Day 15, a single blood sample was collected within 4 hours of study product administration.

Population: Measure was not analyzed since only one participant aged \<18 years was enrolled and no aggregate results were available for posting.

Plasma tecovirimat concentrations were quantified using validated liquid chromatography tandem mass spectrometry (LC-MS/MS) methods. The lower limit of quantification was 5.0 ng/mL.

Outcome measures

Outcome data not reported

Adverse Events

Tecovirimat (Arm A)

Serious events: 4 serious events

Other events: 7 other events

Deaths: 0 deaths

Tecovirimat (Arm A) to Open-Label Tecovirimat (Arm C)

Serious events: 2 serious events

Other events: 12 other events

Deaths: 0 deaths

Placebo (Arm B)

Serious events: 0 serious events

Other events: 4 other events

Deaths: 0 deaths

Placebo (Arm B) to Open-Label Tecovirimat (Arm C)

Serious events: 2 serious events

Other events: 9 other events

Deaths: 0 deaths

Open-Label Tecovirimat (Arm C)

Serious events: 14 serious events

Other events: 14 other events

Deaths: 0 deaths

Serious adverse events

Measure	Tecovirimat (Arm A) n=267 participants at risk Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Tecovirimat (Arm A) to Open-Label Tecovirimat (Arm C) n=23 participants at risk Participants randomized to tecovirimat who started open-label tecovirimat.	Placebo (Arm B) n=132 participants at risk Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) to Open-Label Tecovirimat (Arm C) n=13 participants at risk Participants randomized to placebo who started open-label tecovirimat.	Open-Label Tecovirimat (Arm C) n=281 participants at risk Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Blood and lymphatic system disorders Lymphadenopathy	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Immune system disorders Hypersensitivity	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	7.7% 1/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Abscess limb	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Enterocolitis bacterial	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Monkeypox	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	1.1% 3/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Peritonsillar abscess	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	7.7% 1/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Pneumonia	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.71% 2/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Proctitis viral	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Rectal abscess	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Skin infection	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	7.7% 1/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Investigations Alanine aminotransferase increased	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Investigations Haemoglobin decreased	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.71% 2/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Metabolism and nutrition disorders Diabetic ketoacidosis	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Nervous system disorders Toxic encephalopathy	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Renal and urinary disorders Acute kidney injury	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Skin and subcutaneous tissue disorders Skin ulcer	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible

Other adverse events

Measure	Tecovirimat (Arm A) n=267 participants at risk Participants randomized to tecovirimat. Tecovirimat Oral Capsule: * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days	Tecovirimat (Arm A) to Open-Label Tecovirimat (Arm C) n=23 participants at risk Participants randomized to tecovirimat who started open-label tecovirimat.	Placebo (Arm B) n=132 participants at risk Participants randomized to placebo. Placebo for Tecovirimat: * Participants weighing 25 kg to less than 40 kg - Placebo for Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Placebo for Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Placebo for Tecovirimat 600 mg every 8 hours for 14 days	Placebo (Arm B) to Open-Label Tecovirimat (Arm C) n=13 participants at risk Participants randomized to placebo who started open-label tecovirimat.	Open-Label Tecovirimat (Arm C) n=281 participants at risk Participants assigned to open-label tecovirimat. Tecovirimat Oral Capsule (Open Label): * Participants weighing \<3 kg - Tecovirimat 33.3 mg every 12 hours for 14 days * Participants weighing 3 kg to less than 6 kg- Tecovirimat 50 mg every 12 hours for 14 days * Participants weighing 6 kg to less than 13 kg - Tecovirimat 100 mg every 12 hours for 14 days * Participants weighing 13 kg to less than 25 kg - Tecovirimat 200 mg every 12 hours for 14 days * Participants weighing 25 kg to less than 40 kg - Tecovirimat 400 mg every 12 hours for 14 days * Participants weighing 40 kg to less than 120 kg - Tecovirimat 600 mg every 12 hours for 14 days * Participants weighing 120 kg and over - Tecovirimat 600 mg every 8 hours for 14 days
Ear and labyrinth disorders Tinnitus	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Gastrointestinal disorders Diarrhoea	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Blood and lymphatic system disorders Lymphadenopathy	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Gastrointestinal disorders Nausea	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	1.5% 2/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Gastrointestinal disorders Proctalgia	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	17.4% 4/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	15.4% 2/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Gastrointestinal disorders Vomiting	0.75% 2/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
General disorders Chills	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
General disorders Fatigue	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
General disorders Mass	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
General disorders Swelling	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Acute HIV infection	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Cellulitis	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Herpes simplex anorectal	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Monkeypox	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	17.4% 4/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	38.5% 5/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Infections and infestations Staphylococcal infection	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Investigations Alanine aminotransferase increased	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.71% 2/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Investigations Aspartate aminotransferase increased	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.71% 2/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Investigations Blood creatinine increased	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Investigations Glomerular filtration rate decreased	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Metabolism and nutrition disorders Abnormal loss of weight	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Metabolism and nutrition disorders Decreased appetite	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Metabolism and nutrition disorders Hypoglycaemia	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Musculoskeletal and connective tissue disorders Arthralgia	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Musculoskeletal and connective tissue disorders Back pain	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Nervous system disorders Dizziness	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Nervous system disorders Headache	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.71% 2/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Psychiatric disorders Anxiety	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Psychiatric disorders Depression	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Psychiatric disorders Suicidal ideation	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.36% 1/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Reproductive system and breast disorders Paraphimosis	0.37% 1/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Reproductive system and breast disorders Penile pain	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Reproductive system and breast disorders Penile swelling	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	7.7% 1/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Respiratory, thoracic and mediastinal disorders Oropharyngeal pain	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	7.7% 1/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Skin and subcutaneous tissue disorders Drug eruption	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.76% 1/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Skin and subcutaneous tissue disorders Pain of skin	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible
Skin and subcutaneous tissue disorders Skin ulcer	0.00% 0/267 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	4.3% 1/23 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/132 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/13 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible	0.00% 0/281 • From study entry to study completion at Day 57 or premature study discontinuation. AEs that led to change in study treatment regardless of grade, met serious AE definition or expedited AE reporting requirement, or were Grade 3 or higher were reported and graded using DAIDS AE Grading Table (v2.1). Participants who started open-label tecovirimat were reported separately from their initial treatment arm, thus: at Risk (Arm A) = Started Treatment (Arm A) - Started Open-Label (Arm A) at Risk (Arm B) = Started Treatment (Arm B) - Started Open-Label (Arm B) - 1 ineligible

Additional Information

ACTG Clinicaltrials.gov Coordinator

ACTG Network Coordinating Center, Social and Scientific Systems, a DLH Holdings Company

Phone: (301) 628-3348

Email: ACTGCT.gov@fstrf.org

Results disclosure agreements

• Principal investigator is a sponsor employee In accordance with the Clinical Trials Agreement between NIAID (DAIDS) and company collaborators, NIAID (DAIDS) provides companies with a copy of any abstract, press release, or manuscript prior to submission for publication with sufficient time for company review and comment. The publication/other disclosure can be delayed for up to 30 additional business days for manuscripts and five (5) business days for abstracts, to preserve U.S. or foreign patent or other intellectual property rights.
• Publication restrictions are in place

Restriction type: OTHER