Nirsevimab Effectiveness Against Cases of Respiratory Syncytial Virus Bronchiolitis Hospitalised in Paediatric Intensive Care Units in France, September 2023–January 2024
Juliette Paireau, C. Durand, S. Raimbault, Joséphine Cazaubon, Guillaume Mortamet, Delphine Viriot, Christophe Milési, Elise Daudens‐Vaysse, Dominique Ploin, Sabrina Tessier, Noémie Vanel, J. Chappert, Karine Levieux, R. Ollivier, Jamel Daoudi, B. Coignard, Stéphane Leteurtre, Isabelle Parent‐du‐Châtelet, Sophie Vaux
Abstract
In September 2023, France was one of the first countries that started a national immunisation campaign with nirsevimab, a new monoclonal antibody against respiratory syncytial virus (RSV). Using data from a network of paediatric intensive care units (PICUs), we aimed to estimate nirsevimab effectiveness against severe cases of RSV bronchiolitis in France. We conducted a case-control study based on the test-negative design and included 288 infants reported by 20 PICUs. We estimated nirsevimab effectiveness at 75.9% (48.5-88.7) in the main analysis and 80.6% (61.6-90.3) and 80.4% (61.7-89.9) in two sensitivity analyses. These real-world estimates confirmed the efficacy observed in clinical studies.