Trial Outcomes & Findings for Evaluate the Safety and Tolerability, for Nirsevimab in Immunocompromised Children (NCT NCT04484935)

Last Updated: 2023-11-15

Results Overview

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the treatment. TEAEs were AEs whose onset occurred after receiving nirsevimab and within 360 days post dose. A TESAE was any AE that resulted in death, was life-threatening, required inpatient hospitalization, resulted in persistent or significant disability/incapacity, was a congenital abnormality, or was medically significant. AESIs were defined as AEs of immediate (type I) hypersensitivity (including anaphylaxis), thrombocytopenia, and immune complex disease following the administration of nirsevimab based on investigator assessment and Medical Dictionary for Regulatory Activities (MedDRA) preferred term (PT) codes. An NOCD was a newly diagnosed medical condition of a chronic, ongoing nature post administration of treatment.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

100 participants

Primary outcome timeframe

TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose

Results posted on

2023-11-15

Participant Flow

This Phase 2, open-label, uncontrolled, single-dose study was conducted at 28 investigational sites in 8 countries (Belgium, Japan, Poland, South Africa, Spain, Ukraine, United Kingdom and United States) in immunocompromised children who were \<=24 months of age at the time of enrollment between 19 Aug 2020 and 17 Feb 2023.

This study consisted of a screening period (Visit 1, Day -30 to Day -1); a dosing visit (Visit 2, Day 1) where participants received treatment with nirsevimab and a follow-up period up to Day 361 (Visit 3 to 7). A total of 100 children were enrolled in this study.

Participant milestones

Participant milestones
Measure	Nirsevimab 50 mg/100 mg Participants in their first year of life with a body weight \<5 kilograms (kg) received a single fixed intramuscular (IM) dose of 50 milligram (mg) nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Overall Study STARTED	48	52
Overall Study COMPLETED	45	49
Overall Study NOT COMPLETED	3	3

Reasons for withdrawal

Reasons for withdrawal
Measure	Nirsevimab 50 mg/100 mg Participants in their first year of life with a body weight \<5 kilograms (kg) received a single fixed intramuscular (IM) dose of 50 milligram (mg) nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Overall Study Other	0	1
Overall Study Withdrawal by parent/guardian	0	1
Overall Study Lost to Follow-up	1	0
Overall Study Death	2	1

Baseline Characteristics

Evaluate the Safety and Tolerability, for Nirsevimab in Immunocompromised Children

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Nirsevimab 50 mg/100 mg n=48 Participants Participants in their first year of life with a body weight \<5 kg received a single fixed IM dose of 50 mg nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg n=52 Participants Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.	Total n=100 Participants Total of all reporting groups
Age, Continuous	7.64 months STANDARD_DEVIATION 3.270 • n=5 Participants	17.90 months STANDARD_DEVIATION 3.748 • n=7 Participants	12.97 months STANDARD_DEVIATION 6.232 • n=5 Participants
Sex: Female, Male Female	18 Participants n=5 Participants	17 Participants n=7 Participants	35 Participants n=5 Participants
Sex: Female, Male Male	30 Participants n=5 Participants	35 Participants n=7 Participants	65 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	4 Participants n=5 Participants	3 Participants n=7 Participants	7 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	44 Participants n=5 Participants	49 Participants n=7 Participants	93 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race/Ethnicity, Customized Asian	16 Participants n=5 Participants	12 Participants n=7 Participants	28 Participants n=5 Participants
Race/Ethnicity, Customized American Indian or Alaskan Native	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race/Ethnicity, Customized Black or African American	9 Participants n=5 Participants	11 Participants n=7 Participants	20 Participants n=5 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race/Ethnicity, Customized White	20 Participants n=5 Participants	25 Participants n=7 Participants	45 Participants n=5 Participants
Race/Ethnicity, Customized Other	2 Participants n=5 Participants	2 Participants n=7 Participants	4 Participants n=5 Participants
Race/Ethnicity, Customized Multiple categories checked	0 Participants n=5 Participants	2 Participants n=7 Participants	2 Participants n=5 Participants

PRIMARY outcome

Timeframe: TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose

Population: The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.

Outcome measures

Outcome measures
Measure	Nirsevimab 50 mg/100 mg n=48 Participants Participants in their first year of life with a body weight \<5 kg received a single fixed IM dose of 50 mg nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg n=52 Participants Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious AEs (TESAEs), AEs of Special Interest (AESIs), and New Onset Chronic Disease (NOCDs) AESI based on investigator assessment	3 Participants	2 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious AEs (TESAEs), AEs of Special Interest (AESIs), and New Onset Chronic Disease (NOCDs) Any TEAE	36 Participants	45 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious AEs (TESAEs), AEs of Special Interest (AESIs), and New Onset Chronic Disease (NOCDs) TESAE	12 Participants	20 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious AEs (TESAEs), AEs of Special Interest (AESIs), and New Onset Chronic Disease (NOCDs) AESI based on selected MedDRA PT codes	16 Participants	13 Participants
Number of Participants With Treatment-Emergent Adverse Events (TEAEs), Treatment-Emergent Serious AEs (TESAEs), AEs of Special Interest (AESIs), and New Onset Chronic Disease (NOCDs) NOCD	0 Participants	0 Participants

SECONDARY outcome

Timeframe: Baseline (Day 1) and on Days 8 (for Japanese participants), 31, 151 and 361

Population: The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab. Only those participants with data available are included in the analysis.

Serum concentrations of nirsevimab at selected time points were evaluated to confirm that adequate exposures for protection from respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) are maintained for at least 5 months after dosing.

Outcome measures

Outcome measures
Measure	Nirsevimab 50 mg/100 mg n=48 Participants Participants in their first year of life with a body weight \<5 kg received a single fixed IM dose of 50 mg nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg n=52 Participants Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Serum Concentrations of Nirsevimab Day 31	66.00 mcg/mL Geometric Coefficient of Variation 141.06	109.77 mcg/mL Geometric Coefficient of Variation 91.74
Serum Concentrations of Nirsevimab Day 151	19.80 mcg/mL Geometric Coefficient of Variation 101.19	24.14 mcg/mL Geometric Coefficient of Variation 121.54
Serum Concentrations of Nirsevimab Day 361	1.86 mcg/mL Geometric Coefficient of Variation 119.96	1.93 mcg/mL Geometric Coefficient of Variation 158.95
Serum Concentrations of Nirsevimab Baseline (Day 1)	NA mcg/mL Geometric Coefficient of Variation NA Data was below the lower limit of quantification \[0.5 microgram (mcg)/mL\]	NA mcg/mL Geometric Coefficient of Variation NA Data was below the lower limit of quantification (0.5 mcg/mL)
Serum Concentrations of Nirsevimab Day 8	139.24 mcg/mL Geometric Coefficient of Variation 22.26	206.79 mcg/mL Geometric Coefficient of Variation 16.58

SECONDARY outcome

Timeframe: Baseline (Day 1) and on Days 31, 151 and 361

Population: The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab. Only those participants with data available were analyzed.

Blood samples were analyzed for the presence of ADAs for nirsevimab using validated assays.

Outcome measures

Outcome measures
Measure	Nirsevimab 50 mg/100 mg n=48 Participants Participants in their first year of life with a body weight \<5 kg received a single fixed IM dose of 50 mg nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg n=52 Participants Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Number of Participants With Anti-Drug Antibody (ADA) Response to Nirsevimab Day 31	0 Participants	1 Participants
Number of Participants With Anti-Drug Antibody (ADA) Response to Nirsevimab Day 1	0 Participants	0 Participants
Number of Participants With Anti-Drug Antibody (ADA) Response to Nirsevimab Day 151	1 Participants	0 Participants
Number of Participants With Anti-Drug Antibody (ADA) Response to Nirsevimab Day 361	2 Participants	7 Participants

SECONDARY outcome

Timeframe: Through 150 days post dose

Population: The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.

Number of participants with LRTI and hospitalizations due to reverse transcriptase-polymerase chain reaction (RT-PCR)-confirmed RSV was assessed. MA RSV LRTI consisted of participants with protocol-defined LRTI, positive central RT-PCR RSV test result, Investigator assessed LRTI at an inpatient or outpatient setting. MA RSV LRTI with hospitalization consisted of participants with protocol-defined LRTI, positive central RT-PCR RSV test result, Investigator assessed LRTI at an inpatient setting.

Outcome measures

Outcome measures
Measure	Nirsevimab 50 mg/100 mg n=48 Participants Participants in their first year of life with a body weight \<5 kg received a single fixed IM dose of 50 mg nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg n=52 Participants Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Number of Participants With Medically Attended (MA) RSV LRTI (Inpatient and Outpatient) and Hospitalizations MA RSV LRTI	0 Participants	0 Participants
Number of Participants With Medically Attended (MA) RSV LRTI (Inpatient and Outpatient) and Hospitalizations MA RSV LRTI with hospitalization	0 Participants	0 Participants

Adverse Events

Nirsevimab 50 mg/100 mg

Serious events: 12 serious events

Other events: 35 other events

Deaths: 2 deaths

Nirsevimab 200 mg

Serious events: 20 serious events

Other events: 41 other events

Deaths: 1 deaths

Serious adverse events

Other adverse events

Additional Information

Global Clinical Lead

AstraZeneca

Phone: 1-877-240-9479

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Measure	Nirsevimab 50 mg/100 mg n=48 participants at risk Participants in their first year of life with a body weight \<5 kg received a single fixed IM dose of 50 mg nirsevimab and those with body weight \>=5 kg received a single fixed IM dose of 100 mg nirsevimab.	Nirsevimab 200 mg n=52 participants at risk Participants in their second year of life received a single fixed IM dose of 200 mg (2 × 100 mg) of nirsevimab.
Infections and infestations Hand-foot-and-mouth disease	4.2% 2/48 • Number of events 2 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Lower respiratory tract infection	6.2% 3/48 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Nasopharyngitis	12.5% 6/48 • Number of events 13 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	11.5% 6/52 • Number of events 9 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Otitis media	10.4% 5/48 • Number of events 7 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	11.5% 6/52 • Number of events 7 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Otitis media acute	4.2% 2/48 • Number of events 9 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	7.7% 4/52 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Rhinitis	4.2% 2/48 • Number of events 2 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	9.6% 5/52 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Upper respiratory tract infection	37.5% 18/48 • Number of events 49 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	34.6% 18/52 • Number of events 33 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Viral upper respiratory tract infection	8.3% 4/48 • Number of events 7 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Blood and lymphatic system disorders Anaemia	6.2% 3/48 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Respiratory, thoracic and mediastinal disorders Cough	12.5% 6/48 • Number of events 6 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	7.7% 4/52 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Respiratory, thoracic and mediastinal disorders Nasal congestion	2.1% 1/48 • Number of events 1 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Respiratory, thoracic and mediastinal disorders Rhinorrhoea	12.5% 6/48 • Number of events 11 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	13.5% 7/52 • Number of events 9 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Skin and subcutaneous tissue disorders Dermatitis diaper	10.4% 5/48 • Number of events 6 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	15.4% 8/52 • Number of events 8 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Skin and subcutaneous tissue disorders Dry skin	8.3% 4/48 • Number of events 4 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	1.9% 1/52 • Number of events 1 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Skin and subcutaneous tissue disorders Eczema infantile	8.3% 4/48 • Number of events 4 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	0.00% 0/52 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Skin and subcutaneous tissue disorders Rash	8.3% 4/48 • Number of events 6 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	1.9% 1/52 • Number of events 1 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Skin and subcutaneous tissue disorders Urticaria	6.2% 3/48 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	0.00% 0/52 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Gastrointestinal disorders Abdominal pain	2.1% 1/48 • Number of events 1 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Blood and lymphatic system disorders Febrile neutropenia	6.2% 3/48 • Number of events 4 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	3.8% 2/52 • Number of events 4 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Gastrointestinal disorders Constipation	8.3% 4/48 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	3.8% 2/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Gastrointestinal disorders Diarrhoea	16.7% 8/48 • Number of events 11 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	19.2% 10/52 • Number of events 15 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Gastrointestinal disorders Vomiting	16.7% 8/48 • Number of events 13 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	25.0% 13/52 • Number of events 16 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
General disorders Pyrexia	27.1% 13/48 • Number of events 25 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	25.0% 13/52 • Number of events 27 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations COVID-19	8.3% 4/48 • Number of events 4 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	23.1% 12/52 • Number of events 12 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Conjunctivitis	8.3% 4/48 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	3.8% 2/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Ear infection	0.00% 0/48 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Blood and lymphatic system disorders Neutropenia	2.1% 1/48 • Number of events 1 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	5.8% 3/52 • Number of events 3 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Gastroenteritis	2.1% 1/48 • Number of events 2 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	11.5% 6/52 • Number of events 7 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Gastroenteritis viral	6.2% 3/48 • Number of events 5 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	7.7% 4/52 • Number of events 4 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.
Infections and infestations Gastrointestinal viral infection	0.00% 0/48 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.	7.7% 4/52 • Number of events 9 • The TEAEs were collected from the first dose administration (Day 1) up to 360 days post dose The As-treated population consisted of all participants who were enrolled and received any dose of nirsevimab.