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Real-World Effectiveness of Nirsevimab Against Respiratory Syncytial Virus Disease in Infants: A Systematic Review and Meta-Analysis
22 Pages Posted: 15 Jan 2025
More...Abstract
Background: Nirsevimab was approved in 2023, and all-infant programs began to be implemented in several high-income countries to prevent lower respiratory tract illness (LRTI) caused by respiratory syncytial virus (RSV). Knowledge of real-world effectiveness (RWE) of broad nirsevimab programmes is crucial to validate the benefits observed in clinical trials and guide immunisation policy. We assessed the RWE of nirsevimab in populations where infant immunisation programmes were introduced.
Methods: We searched Ovid MEDLINE, Ovid Embase, Web of Science, Scopus, Global health, and MedRxiv up to December 13, 2024 to identify studies reporting the RWE of nirsevimab. Pooled analyses were conducted using inverse-variance random-effects models with Hartung-Knapp-Sidik-Jonkman variance correction for RSV-related hospitalisations, ICU admissions, and RSV-related LRTI incidence. For length of hospital stay (LoHS), we employed a restricted maximum likelihood random-effects model to estimate the weighted mean difference (WMD) between the nirsevimab and control groups. Results of RWE are reported as odds ratio (OR) and WMD with 95% confidence intervals (CIs). This study is registered with PROSPERO, CRD42024628782.
Findings: We identified and screened 1215 records, of which 28 studies from five countries (France, Italy, Luxembourg, Spain, United States) were included. The pooled analysis revealed that nirsevimab significantly reduced the risk of RSV-related hospitalisation (OR: 0.14; 95% CI: 0.11–0.20; p <0.001, I2 = 65.3%), ICU admission (OR: 0.17; 95% CI: 0.10–0.31; p<0.001, I2 = 58.6%), and LRTI incidence (OR: 0.27; 95% CI: 0.23–0.32; p<0.001, I2 = 0.0%). In the subgroup analysis, we found that the RWE of nirsevimab for RSV-related hospitalisation varied by age and country, with a stronger treatment effect in infants over 3 months old and in the US. However, no significant difference in LoHS was found between the nirsevimab and control groups (WMD: 0.10; 95% CI: -0.59–0.79; p = 0.789, I2 = 79.3%).
Interpretation: Our findings indicate that the benefits of nirsevimab observed in clinical trials are also evident in real-world settings, effectively reducing the burden of RSV disease in infants, and reducing healthcare utilisation. This study highlights the importance of tailored immunisation programmes, taking into account variations in effectiveness by age and population setting.
Keywords: RSV, nirsevimab, immunisation
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