BEYFORTUS™ (Nirsevimab) Effectiveness Against Medically-Attended RSV Events in Infants (BEAR Study)

NCT06325332 | Completed FDA Drug

• 1 other identifier: RSV00080
• Study Type: observational
• Target: 49,680
• Locations: 1 country
• Sites: 1

Brief Summary

The primary objectives of the study are: To estimate the effectiveness of nirsevimab against polymerase chain reaction (PCR)-confirmed RSV (1) lower respiratory tract (LRTD) and (2) related medical encounters. the secondary objectives are:

1. 1.To estimate the effectiveness of nirsevimab against medical encounters with a respiratory related diagnosis.
2. 2.To estimate the effectiveness of nirsevimab against medical encounters with an LRTD diagnosis.
3. 3.To estimate the impact of nirsevimab on PCR-confirmed RSV.
4. 4.To estimate the impact of nirsevimab on medical encounters with an otitis media diagnosis.
5. 5.To estimate the impact of nirsevimab on antibiotic prescription.

Conditions

Respiratory Syncytial Virus

Keywords

RSV

Outcome Measures

Primary Outcomes (2)

• Incidence of first episodes of polymerase chain reaction (PCR)-confirmed RSV with an lower respiratory tract disease (LRTD)

  Incidence of first episodes of polymerase chain reaction (PCR)-confirmed RSV with an lower respiratory tract disease (LRTD) diagnosis identified using International Classification of Diseases, Tenth Revision (ICD)

  Approximately 6 months

• Number of medical encounters associated with the first episode of PCR-confirmed RSV with a LRTD diagnosis

  Number of medical encounters associated with the first episode of PCR-confirmed RSV with a LRTD diagnosis identified using ICD-10 codes: outpatient (OP) visits, emergency department (ED) visits, inpatient (IP) hospitalizations or intensive care unit (ICU) hospitalizations.

  Approximately 6 months

Secondary Outcomes (5)

• Number of respiratory-related medical encounters

  Approximately 6 months

• Number of respiratory-related medical encounters for LRTD by ICD-10 codes

  Approximately 6 months

• Incidence of PCR-confirmed RSV (first occurrence of season)

  Approximately 6 months

• Number of medical encounters for otitis media by ICD-10 codes

  Approximately 6 months

• Number of antibiotic prescriptions by National Drug Code (NDC) codes

  Approximately 6 months

Study Arms (4)

Cohort 1: Nirsevimab-Exposed Cohort

Full-term (born ≥ 37 weeks gestational age) infants born on or after 01 April 2023, without a high-risk condition, who receive nirsevimab before or during their first RSV season per recommendations, ie, before or during the 2023-2024 RSV season.

Other: Nirsevimab

Cohort 2: Comparator Cohort

Full-term (born ≥ 37 weeks gestational age) infants born on or after 01 April 2023, without a high-risk condition, who do not receive nirsevimab before or during the 2023-2024 RSV season.

Cohort 3: Historical Control Cohort

Full-term (born ≥ 37 weeks gestational age) infants without a high-risk condition from previous RSV seasons 2016-2017, 2017-2018, 2018-2019, 2019-2020, and 2022-2023. The 2020-2021 and 2021-2022 seasons are excluded due to low circulation of RSV during the COVID-19 pandemic. Historical seasons' data are intended for descriptive purpose only, to contextualize the impact of the treatment during the 2023-2024 season.

Cohort 4: Infant Cohort with High-Risk Conditions

Infants born \< 37 weeks gestational age and those diagnosed with a high-risk condition between birth and the end of the observation period (regardless of gestational age at birth), will be considered infants with high-risk conditions. Infants with high-risk conditions will be excluded from Cohort 1, Cohort 2, and Cohort 3. Descriptive statistics will be separately assessed for this high-risk cohort.

Interventions

Nirsevimab OTHER

Route of Administration: Intramuscular Pharmaceutical Form: Solution for injection

Also known as: Beyfortus™

Cohort 1: Nirsevimab-Exposed Cohort

Eligibility Criteria

• Age: 0 Days - 12 Months
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)
• Sampling Method: Probability Sample

Study Population

The study is an observational, retrospective cohort study designed to evaluate the effectiveness of nirsevimab to prevent RSV-confirmed respiratory-related medical encounters and health care utilization in infants entering their first RSV season compared to no treatment in the United States. The source population is infants ≥ 37 weeks gestational age and aged 0 to 12 months (calendar age) entering their first RSV season and without significant medical history. There is also a high-risk infant population with infants \< 37 WGA and aged 0 to 12 months (calendar age), entering their first RSV season and infants ≥ 37 weeks with significant medical history diagnosed at birth up to the end of the observation period (ie, 30 April 2024). The study will aim to enroll approximately 33,000 infants.

You may qualify if:

• The Kaiser Permanente Northern California, USA (KPNC) member born on or after 01 April 2023 for Cohort 1 and Cohort 2.
• Eligible to receive nirsevimab as defined by the product indication.
• KPNC infants entering their first RSV season.

You may not qualify if:

• Mother was administered an RSV vaccine during her pregnancy with the infant participant.
• Mother of infant participant was not a KPNC member during pregnancy.
• Mother did not deliver the infant participant at a KPNC facility.
• Infant receipt of other RSV pre-exposure prophylaxis (ie, Palivizumab).
• Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

Sponsors & Collaborators

• Sanofi Pasteur, a Sanofi Company: lead

Study Sites (1)

Kaiser Permanente Northern California: Site number 0001

Oakland, California, 94612, United States

Location

MeSH Terms

Interventions

nirsevimab

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 15, 2024
• First Posted: March 22, 2024
• Study Start: April 1, 2024
• Primary Completion: June 30, 2025
• Study Completion: June 30, 2025
• Last Updated: November 5, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will share

Locations

US (1)