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Multicenter Study
. 2025 Feb 1;184(2):171.
doi: 10.1007/s00431-025-06008-9.

Nirsevimab effectiveness on paediatric emergency visits for RSV bronchiolitis: a test-negative design study

Lea Lenglart  1   2 , Corinne Levy  3   4   5   6 , Romain Basmaci  7   6   8 , Karine Levieux  6   9 , Rolf Kramer  10 , Karine Mari  10 , Stéphane Béchet  3 , Elise Launay  6   9 , Laure Cohen  8 , Camille Aupiais  6   11 , Loic de Pontual  6   11 , Alexis Rybak  3   6   12 , Yannis Lassoued  7   13 , Naim Ouldali  7   6   13 , Robert Cohen  3   4   5   6
Affiliations
Multicenter Study

Nirsevimab effectiveness on paediatric emergency visits for RSV bronchiolitis: a test-negative design study

Lea Lenglart et al. Eur J Pediatr. .

Abstract

Bronchiolitis is one of the leading reasons for paediatric emergency department (PED) visits. France was one of the few countries in the world to implement nirsevimab during winter 2023-2024 in order to reduce the burden of bronchiolitis each year. We conducted a test-negative design study, including all infants younger than 1, diagnosed with a first episode of bronchiolitis. We included all cases presenting to the PED of five university hospitals across France, between October 1, 2023, and February 29, 2024, and undergoing a nasopharyngeal sample for RSV testing. Case patients were the RSV-positive bronchiolitis and control patients the RSV-negative. As a follow-up, all parents were contacted by e-mail 15 days after inclusion. We included 383 bronchiolitis patients, of which 274 tested positive for RSV (75.2%). Among case patients, 27/274 (9.8%) received nirsevimab, compared to 50/109 (46.2%) among control patients. Nirsevimab had an adjusted estimated effectiveness of 82.5% (95% CI [68.0-90.8]) at PEDs. Sensitivity analyses found similar results. At 15-day follow-up, characteristics were similar between children immunized by nirsevimab or not.

Conclusion: Our findings advocate for nirsevimab widespread adoption to alleviate the burden of RSV bronchiolitis in paediatric emergency departments.

Trial registration: NCT04743609 (date of registration: February 4, 2021).

What is known: • Each year, RSV-bronchiolitis places significant pressure on pediatric emergency services. • France is one of the first countries in the world to have implemented nirsevimab in septembre 2023.

What is new: • Nirsevimab effectiveness on pediatric emergency visits for RSV-bronchiolitis has been estimated to 82.5% (95% CI [68.0-90.8]) in our study. • The effectiveness was as strong to prevent hospitalizations and sever illnesses.

Keywords: Bronchiolitis; Nirsevimab; Respiratory syncytial virus.

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Conflict of interest statement

Declarations. Ethics approval: The study protocol was written in accordance with the Declaration of Helsinki, approved by the ethics committee CPP Ile-de-France 1 (2020-A02876-33) and registered on February 4, 2021, at ClinicalTrials.gov (NCT04743609). Consent to participate: Written informed consent was obtained from the parents. Conflict of interest: RK and KM are Sanofi employees and hold shares or stock options in the company.

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References

    1. Troeger C, Blacker B, Khalil IA et al (2018) Estimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Infect Dis 18(11):1191–1210. https://doi.org/10.1016/S1473-3099(18)30310-4 - DOI
    1. Shi T, McAllister DA, O’Brien KL et al (2017) Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: a systematic review and modelling study. Lancet Lond Engl 390(10098):946–958. https://doi.org/10.1016/S0140-6736(17)30938-8 - DOI
    1. Brault A, Pontais I, Enouf V et al (2024) Effect of nirsevimab on hospitalisations for respiratory syncytial virus bronchiolitis in France, 2023–24: a modelling study. Lancet Child Adolesc Health 8(10):721–729. https://doi.org/10.1016/S2352-4642(24)00143-3 - DOI - PubMed
    1. Drysdale SB, Cathie K, Flamein F et al (2023) Nirsevimab for prevention of hospitalizations due to RSV in infants. N Engl J Med 389(26):2425–2435. https://doi.org/10.1056/NEJMoa2309189 - DOI - PubMed
    1. Moline HL, Tannis A, Toepfer AP et al (2024) Early estimate of nirsevimab effectiveness for prevention of respiratory syncytial virus–associated hospitalization among infants entering their first respiratory syncytial virus season — new vaccine surveillance network, October 2023–February 2024. MMWR Morb Mortal Wkly Rep 73(9):209–214. https://doi.org/10.15585/mmwr.mm7309a4 - DOI - PubMed - PMC

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