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

NCT ID: NCT06325332

Last Updated: 2025-11-05

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

49680 participants

Study Classification

OBSERVATIONAL

Study Start Date

2024-04-01

Study Completion Date

2025-06-30

Brief Summary

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

Detailed Description

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Conditions

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Respiratory Syncytial Virus

Study Design

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Observational Model Type

COHORT

Study Time Perspective

RETROSPECTIVE

Study Groups

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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.

Nirsevimab

Intervention Type OTHER

Route of Administration: Intramuscular Pharmaceutical Form: Solution for injection

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.

No interventions assigned to this group

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.

No interventions assigned to this group

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.

No interventions assigned to this group

Interventions

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Nirsevimab

Route of Administration: Intramuscular Pharmaceutical Form: Solution for injection

Intervention Type OTHER

Other Intervention Names

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Beyfortus™

Eligibility Criteria

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Inclusion Criteria

* 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.

Exclusion Criteria

* 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.
Minimum Eligible Age

0 Days

Maximum Eligible Age

12 Months

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Sanofi Pasteur, a Sanofi Company

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Kaiser Permanente Northern California: Site number 0001

Oakland, California, United States

Site Status

Countries

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United States

Other Identifiers

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RSV00080

Identifier Type: -

Identifier Source: org_study_id

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