Effectiveness of nirsevimab against hospitalisation for RSV-bronchiolitis during high RSV-B circulation in the second year of nationwide implementation in France: a test-negative case-control study.

ABSTRACT:

Background

Nirsevimab was first introduced in September 2023, showing strong real-world effectiveness in preventing hospitalised RSV-bronchiolitis. RSV-A circulation predominated during 2023-2024, whereas RSV-B was frequent in 2024-2025. Recent reports indicated resistance to nirsevimab in RSV-B strains in France. We aimed to assess the effectiveness of large-scale nirsevimab implementation against hospitalised RSV-bronchiolitis during high RSV-B circulation.

Methods

A test-negative case-control study was conducted using a national hospital-based surveillance system. All children <12 months hospitalised for bronchiolitis and tested for RSV in 12 French hospitals from October 10, 2024 to March 15, 2025, were included. Cases were RSV-positive bronchiolitis; controls were RSV-n

SUBMITTER: Furgier A 

PROVIDER: S-EPMC12598395 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature