Trial Outcomes & Findings for Study on an Investigational Yellow Fever Vaccine Compared With Stamaril in Adults in Europe and Asia (NCT NCT05011123)

Last Updated: 2025-05-21

Results Overview

Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value. YF-naive participants (or negative) at baseline corresponded to participants with no detectable YF Ab titers before vaccination. The YF NAb titers were determined using a validated live virus microneutralization (MN) assay. Percentages are rounded off to the tenth decimal place.

Recruitment status

ACTIVE_NOT_RECRUITING

Study phase

PHASE2

Target enrollment

690 participants

Primary outcome timeframe

28 days post dose 1 (Day 29)

Results posted on

2025-05-21

Participant Flow

This study was conducted at 23 sites in 6 countries in Europe and Asia from 07 October 2021 to 25 April 2022. Interim results are presented up to Year 2 follow-up, data base lock (DBL) date of 01 August 2024.

A total of 690 participants were randomized in a 2:1 ratio to receive a single subcutaneous (SC) injection of either yellow fever vaccine (vYF) vaccine or Stamaril. A subset of participants enrolled in European Union (EU) and Asia at selected sites provided an additional post-vaccination blood sample on Day 11 to assess the early immune response elicited by both vaccines in terms of neutralizing antibody (Nab) titers.

Participant milestones

Participant milestones
Measure	vYF 0.5 mL Participants received 1 dose of vYF vaccine 0.5 milliliter (mL) as a SC injection on Day 1.	Stamaril 0.5 mL Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Overall Study STARTED	455	235
Overall Study Randomized and Vaccinated	454	235
Overall Study COMPLETED	407	217
Overall Study NOT COMPLETED	48	18

Reasons for withdrawal

Reasons for withdrawal
Measure	vYF 0.5 mL Participants received 1 dose of vYF vaccine 0.5 milliliter (mL) as a SC injection on Day 1.	Stamaril 0.5 mL Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Overall Study Withdrawal by Subject	4	2
Overall Study Lost to Follow-up	7	6
Overall Study Ongoing at the time of DBL date	36	10
Overall Study Randomized but did not receive vaccination	1	0

Baseline Characteristics

Study on an Investigational Yellow Fever Vaccine Compared With Stamaril in Adults in Europe and Asia

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	vYF 0.5 mL n=455 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.	Total n=690 Participants Total of all reporting groups
Age, Continuous	37.1 Years STANDARD_DEVIATION 11.76 • n=5 Participants	37.1 Years STANDARD_DEVIATION 11.51 • n=7 Participants	37.1 Years STANDARD_DEVIATION 11.67 • n=5 Participants
Sex: Female, Male Female	253 Participants n=5 Participants	136 Participants n=7 Participants	389 Participants n=5 Participants
Sex: Female, Male Male	202 Participants n=5 Participants	99 Participants n=7 Participants	301 Participants n=5 Participants
Race/Ethnicity, Customized American Indian or Alaska Native	1 Participants n=5 Participants	1 Participants n=7 Participants	2 Participants n=5 Participants
Race/Ethnicity, Customized Asian	85 Participants n=5 Participants	43 Participants n=7 Participants	128 Participants n=5 Participants
Race/Ethnicity, Customized Black or African American	5 Participants n=5 Participants	2 Participants n=7 Participants	7 Participants n=5 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race/Ethnicity, Customized White	356 Participants n=5 Participants	187 Participants n=7 Participants	543 Participants n=5 Participants
Race/Ethnicity, Customized Multiple origin	3 Participants n=5 Participants	2 Participants n=7 Participants	5 Participants n=5 Participants
Race/Ethnicity, Customized Not Reported	2 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants
Race/Ethnicity, Customized Unknown	2 Participants n=5 Participants	0 Participants n=7 Participants	2 Participants n=5 Participants

PRIMARY outcome

Timeframe: 28 days post dose 1 (Day 29)

Population: The per-protocol analysis set (PPAS) was a subset of the full analysis set (FAS). The FAS included the subset of randomized participants who received at least 1 dose of the study vaccine or control vaccine and had a valid post-vaccination blood sample result. Only YF-naive participants enrolled in EU with data collected are reported.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=322 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=160 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Percentage of Yellow Fever-naive Participants Who Achieved Seroconversion 28 Days Post Dose 1 Enrolled in European Union	98.1 percentage of participants Interval 96.0 to 99.3	99.4 percentage of participants Interval 96.6 to 100.0

SECONDARY outcome

Timeframe: 28 days post dose 1 (Day 29)

Population: The FAS included the subset of randomized participants who received at least 1 dose of the study vaccine or control vaccine and had a valid post-vaccination blood sample result. Only participants enrolled in EU with data collected are reported.

Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value. The YF NAb titers were determined using a validated live virus MN assay. Percentages are rounded off to the tenth decimal place.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=369 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=190 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Percentage of Participants Who Achieved Seroconversion 28 Days Post Dose 1 Enrolled in European Union	95.9 percentage of participants Interval 93.4 to 97.7	96.8 percentage of participants Interval 93.3 to 98.8

SECONDARY outcome

Timeframe: Days 1, 11, 29, Month 6, Years 1 and 2

Population: FAS: subset of randomized participants who received at least 1 dose of study vaccine or control vaccine and had a valid post-vaccination blood sample result. Day 11: subset of participants enrolled in EU and Asia at selected sites who provided an additional post-vaccination blood sample on Day 11 to assess early immune response elicited by both vaccines in terms of Nab titers. Only participants enrolled in EU and Asia with data collected at specified timepoints are reported.

Seroconversion was defined as a 4-fold increase in Nab titers as compared to the pre-vaccination value: as compared to the Day 1 titers at each timepoint up to Month 6; as compared to the last planned previous timepoint from Year 1 onwards. The YF NAb titers were determined using a validated live virus MN assay. Percentages are rounded off to the tenth decimal place.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=369 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=190 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia EU: Day 11	30.4 percentage of participants Interval 18.8 to 44.1	63.6 percentage of participants Interval 45.1 to 79.6
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia EU: Day 29	95.9 percentage of participants Interval 93.4 to 97.7	96.8 percentage of participants Interval 93.3 to 98.8
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia EU: Month 6	95.8 percentage of participants Interval 93.2 to 97.6	95.2 percentage of participants Interval 91.1 to 97.8
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia EU: Year 1	3.2 percentage of participants Interval 1.6 to 5.7	4.4 percentage of participants Interval 1.9 to 8.4
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia EU: Year 2	0.9 percentage of participants Interval 0.2 to 2.7	3.0 percentage of participants Interval 1.0 to 6.8
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia Asia: Day 11	5.1 percentage of participants Interval 0.6 to 17.3	33.3 percentage of participants Interval 14.6 to 57.0
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia Asia: Day 29	87.2 percentage of participants Interval 77.7 to 93.7	97.6 percentage of participants Interval 87.4 to 99.9
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia Asia: Month 6	85.7 percentage of participants Interval 75.9 to 92.6	100 percentage of participants Interval 91.0 to 100.0
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia Asia: Year 1	1.3 percentage of participants Interval 0.0 to 7.1	0 percentage of participants Interval 0.0 to 9.3
Percentage of Participants Who Achieved Seroconversion Enrolled in European Union and Asia Asia: Year 2	1.3 percentage of participants Interval 0.0 to 7.2	2.5 percentage of participants Interval 0.1 to 13.2

SECONDARY outcome

Timeframe: Days 1, 11, 29, Month 6, Years 1 and 2

Seroprotection was defined as NAb titers \>=threshold of 10 (1/dilution). YF-naive participants (or negative) at baseline corresponded to participants with no detectable YF Ab titers before vaccination. The YF NAb titers were determined using a validated live virus MN assay. Percentages are rounded off to the tenth decimal place.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=371 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=190 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia EU: Day 1	4.3 percentage of participants Interval 2.5 to 6.9	7.9 percentage of participants Interval 4.5 to 12.7
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia EU: Day 11	48.2 percentage of participants Interval 34.7 to 62.0	81.8 percentage of participants Interval 64.5 to 93.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia EU: Day 29	98.6 percentage of participants Interval 96.9 to 99.6	99.5 percentage of participants Interval 97.1 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia EU: Month 6	98.1 percentage of participants Interval 96.0 to 99.2	100 percentage of participants Interval 98.0 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia EU: Year 1	98.5 percentage of participants Interval 96.6 to 99.5	99.5 percentage of participants Interval 97.0 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia EU: Year 2	98.5 percentage of participants Interval 96.5 to 99.5	100 percentage of participants Interval 97.9 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia Asia: Day 1	6.4 percentage of participants Interval 2.1 to 14.3	7.1 percentage of participants Interval 1.5 to 19.5
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia Asia: Day 11	28.2 percentage of participants Interval 15.0 to 44.9	66.7 percentage of participants Interval 43.0 to 85.4
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia Asia: Day 29	96.2 percentage of participants Interval 89.2 to 99.2	100 percentage of participants Interval 91.6 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia Asia: Month 6	96.1 percentage of participants Interval 89.0 to 99.2	100 percentage of participants Interval 91.0 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia Asia: Year 1	94.8 percentage of participants Interval 87.2 to 98.6	100 percentage of participants Interval 91.2 to 100.0
Percentage of Participants Who Achieved Seroprotection to Yellow Fever Virus Enrolled in European Union and Asia Asia: Year 2	96.0 percentage of participants Interval 88.8 to 99.2	100 percentage of participants Interval 91.2 to 100.0

SECONDARY outcome

Timeframe: Days 1, 11, 29, Month 6, Years 1 and 2

GMTs of antibody against YF virus was measured using a validated live virus MN assay.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=371 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=190 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Year 2	310 titer Interval 268.0 to 359.0	349 titer Interval 292.0 to 416.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Day 1	5.62 titer Interval 5.29 to 5.98	6.18 titer Interval 5.52 to 6.92
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Day 11	26.6 titer Interval 14.4 to 49.2	52.3 titer Interval 29.8 to 91.5
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Day 29	2229 titer Interval 1928.0 to 2577.0	1060 titer Interval 884.0 to 1270.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Month 6	562 titer Interval 493.0 to 641.0	425 titer Interval 365.0 to 495.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Year 1	454 titer Interval 391.0 to 527.0	420 titer Interval 353.0 to 499.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Day 1	6.16 titer Interval 5.13 to 7.39	5.63 titer Interval 4.83 to 6.57
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Day 11	10.3 titer Interval 6.36 to 16.7	16.6 titer Interval 10.0 to 27.7
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Day 29	1204 titer Interval 792.0 to 1831.0	1167 titer Interval 843.0 to 1616.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Month 6	495 titer Interval 355.0 to 690.0	398 titer Interval 300.0 to 527.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Year 1	303 titer Interval 209.0 to 438.0	245 titer Interval 174.0 to 344.0
Geometric Mean Titers (GMTs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Year 2	168 titer Interval 127.0 to 223.0	143 titer Interval 104.0 to 196.0

SECONDARY outcome

Timeframe: Days 1, 11, 29, Month 6, Years 1 and 2

GMTs of antibody against YF virus was measured using a validated live virus MN assay. Ratio was calculated as post-vaccination titer at Days 11, 29 and Month 6 to pre-vaccination titer at Day 1; post-vaccination titer at Year 1 to pre-vaccination titer at Month 6; post-vaccination titer at Year 2 to pre-vaccination titer at Year 1.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=369 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=190 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Day 11/Day 1	3.12 ratio Interval 1.85 to 5.27	4.92 ratio Interval 3.02 to 8.03
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Day 29/Day 1	206 ratio Interval 176.0 to 241.0	90.9 ratio Interval 74.1 to 111.0
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Month 6/Day 1	52.3 ratio Interval 45.5 to 60.0	36.7 ratio Interval 30.7 to 43.9
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Year 1/Month 6	0.810 ratio Interval 0.738 to 0.889	0.993 ratio Interval 0.884 to 1.11
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia EU: Year 2/Year 1	0.655 ratio Interval 0.597 to 0.718	0.822 ratio Interval 0.716 to 0.944
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Day 11/Day 1	1.31 ratio Interval 1.04 to 1.65	2.05 ratio Interval 1.36 to 3.08
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Day 29/Day 1	105 ratio Interval 67.0 to 164.0	109 ratio Interval 75.9 to 156.0
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Month 6/Day 1	43.1 ratio Interval 30.0 to 61.7	36.9 ratio Interval 27.4 to 49.8
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Year 1/Month 6	0.607 ratio Interval 0.497 to 0.741	0.601 ratio Interval 0.474 to 0.762
Geometric Mean Titers Ratio (GMTRs) of Antibodies Against Yellow Fever Virus in Participants Enrolled in European Union and Asia Asia: Year 2/Year 1	0.542 ratio Interval 0.452 to 0.649	0.585 ratio Interval 0.47 to 0.729

SECONDARY outcome

Timeframe: Up to 30 minutes post vaccination on Day 1

Population: The safety analysis set (SafAS) included all participants who received at least 1 dose of the study vaccines.

An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, ie, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=454 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Number of Participants With Unsolicited Systemic Adverse Events (AEs)	0 Participants	0 Participants

SECONDARY outcome

Timeframe: Up to 7 days post vaccination (Day 8)

Population: The SafAS included all participants who received at least 1 dose of the study vaccines. Only participants with data collected are reported.

A solicited reaction was an "expected" adverse reaction (AR) (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. An injection site reaction was an AR at and around the injection site of the study vaccine.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=450 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=233 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Number of Participants With Solicited Injection Site Reactions	152 Participants	50 Participants

SECONDARY outcome

Timeframe: Up to 14 days post vaccination (Day 15)

Population: The SafAS included all participants who received at least 1 dose of the study vaccines. Only participants with data collected are reported.

A solicited reaction was an "expected" AR (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. Solicited systemic reactions were systemic AEs observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=450 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=233 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Number of Participants With Solicited Systemic Reactions	222 Participants	126 Participants

SECONDARY outcome

Timeframe: Up to 28 days post vaccination (Day 29)

Population: The SafAS included all participants who received at least 1 dose of the study vaccines.

An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, ie, pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=454 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Number of Participants With Unsolicited Adverse Events	138 Participants	68 Participants

SECONDARY outcome

Timeframe: From the first dose of study vaccine administration (Day 1) up to 6 months post vaccination, approximately up to Day 181

Population: The SafAS included all participants who received at least 1 dose of the study vaccines.

An SAE was any AE that at any dose resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was an important medical event. An AESI (serious or non-serious) was defined as one of scientific and medical concern specific to the Sponsor's study intervention or program, for which ongoing monitoring and rapid communication by the Investigator to the Sponsor could be appropriate. AESIs included serious hypersensitivity/allergic reactions, organ failure/serious viscerotropic events, serious neurologic events.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=454 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Number of Participants With Any Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) up to 6 Months Post-Vaccination SAEs	6 Participants	8 Participants
Number of Participants With Any Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) up to 6 Months Post-Vaccination AESIs	0 Participants	1 Participants

SECONDARY outcome

Timeframe: From the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030

Population: The SafAS included all participants who received at least 1 dose of the study vaccines.

Outcome measures

Outcome measures
Measure	vYF 0.5 mL n=454 Participants Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 Participants Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Number of Participants With Serious Adverse Events and Deaths up to Day 1030 SAEs	11 Participants	11 Participants
Number of Participants With Serious Adverse Events and Deaths up to Day 1030 Deaths	0 Participants	0 Participants

SECONDARY outcome

Timeframe: From the first dose of study vaccine administration (Day 1) up to end of study, approximately 5 years

Outcome measures

Outcome data not reported

Adverse Events

vYF 0.5 mL

Serious events: 11 serious events

Other events: 266 other events

Deaths: 0 deaths

Stamaril 0.5 mL

Serious events: 11 serious events

Other events: 141 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Other adverse events
Measure	vYF 0.5 mL n=454 participants at risk Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 participants at risk Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
General disorders Injection Site Erythema	6.6% 30/454 • Number of events 30 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
General disorders Injection Site Pain	31.7% 144/454 • Number of events 144 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	20.9% 49/235 • Number of events 49 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
General disorders Malaise	23.1% 105/454 • Number of events 105 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	26.0% 61/235 • Number of events 61 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Musculoskeletal and connective tissue disorders Myalgia	27.1% 123/454 • Number of events 123 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	27.7% 65/235 • Number of events 65 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Nervous system disorders Headache	37.0% 168/454 • Number of events 168 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	42.1% 99/235 • Number of events 99 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.

Additional Information

Trial Transparency Team

Sanofi Pasteur

Phone: 800-633-1610 ext: 6#

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee The Sponsor must have the opportunity to review at least 60 days prior to submission for publication or presentation. If review indicates that potentially patentable subject matter would be disclosed, publication or public disclosure may be delayed for a maximum of an additional 60 days to allow for filing the necessary patent applications.
Publication restrictions are in place

Restriction type: OTHER

Measure	vYF 0.5 mL n=454 participants at risk Participants received 1 dose of vYF vaccine 0.5 mL as a SC injection on Day 1.	Stamaril 0.5 mL n=235 participants at risk Participants received 1 dose of Stamaril vaccine 0.5 mL as a SC injection on Day 1.
Blood and lymphatic system disorders Pancytopenia	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Cardiac disorders Acute Myocardial Infarction	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Gastrointestinal disorders Vomiting	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
General disorders Malaise	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Appendicitis	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Covid-19	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	1.3% 3/235 • Number of events 3 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Infectious Pleural Effusion	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Influenza	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Peritonsillitis	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Pneumonia	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Pyelonephritis	0.44% 2/454 • Number of events 2 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Infections and infestations Tonsillitis	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Injury, poisoning and procedural complications Ankle Fracture	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Injury, poisoning and procedural complications Femoral Neck Fracture	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Benign Neoplasm Of Testis	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Neoplasms benign, malignant and unspecified (incl cysts and polyps) Rectal Cancer	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Nervous system disorders Cerebrovascular Accident	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Nervous system disorders Transient Ischaemic Attack	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Psychiatric disorders Depression	0.22% 1/454 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.00% 0/235 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.
Psychiatric disorders Suicidal Ideation	0.00% 0/454 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.	0.43% 1/235 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from the first dose of study vaccine administration (Day 1) up to DBL date of 01 August 2024, approximately up to Day 1030. Analysis was performed on the SafAS. Interim results are presented up to Year 2 follow-up, DBL date of 01 August 2024.