Nirsevimab coverage drives heterogeneous impacts on paediatric emergency department visits for bronchiolitis across Europe: an interrupted time-series analysis

Résumé fourni par la source

Context: Nirsevimab was recently introduced to prevent RSV-bronchiolitis in infants. Despite its proven effectiveness and similar guidelines, the variability in bronchiolitis reduction observed across Europe raised concerns about the underlying drivers. This study explored whether nirsevimab coverage among targeted populations (born in- and out-of-season) could explain this variability. Methods and findings: We conducted a controlled interrupted time-series analysis using data from 27 peadiatric emergency departments across 12 European countries (01/2018-03/2024). Regions were classified as intervention or control based on nirsevimab implementation. Coverage levels were obtained from official regional reports. All bronchiolitis cases aged <12 months were included. We estimated changes in monthly case number by age-groups (0-3 and 3-12 months) and regions during the intervention period (10/2023-03/2024) and examined their correlation to coverage using Pearson’s test. Urinary tract infections served as a control outcome. A total of 107,088 bronchiolitis cases were included. During the intervention period, reductions varied widely across regions and age-groups (from +0.6% [-9.4; +20.5] in 3-12-months-olds in Paris to -61.0% [-67.8; -35.2] in 0-3-months-olds in the Basque country). A strong correlation was observed between coverage and bronchiolitis reduction across age-groups and regions (ρ=-0.86, p=0.001). Trends in bronchiolitis cases in control countries remained stable, as did urinary tract infections cases. Conclusions: This multinational interrupted time-series analysis identified coverage as a key driver of nirsevimab heterogeneous impact on bronchiolitis across age-groups and European regions. Implementation choices across Europe likely influenced coverage, highlighting that nirsevimab benefits depend not only on its intrinsic efficacy, but also on how effectively it is delivered.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.