Impact of Universal Nirsevimab Immunoprophylaxis on Bronchiolitis Hospitalizations and Disease Severity in Neonates: A Real-World Single-Centre Study

(1)

Background

Respiratory syncytial virus (RSV) is the leading cause of neonatal lower respiratory tract infection. We described changes in neonatal bronchiolitis hospitalizations, RSV detection and disease severity across the transition from two seasons without systematic RSV prophylaxis to two seasons following the introduction of universal nirsevimab immunoprophylaxis (Lazio region, December 2024) in a tertiary pediatric center. (2)

Methods

A retrospective, observational study was conducted at “Bambino Gesù” Children’s Hospital IRCCS (Rome, Italy) comparing four consecutive RSV seasons: pre-universal prophylaxis (2022–2024, n = 256) versus post-universal prophylaxis (2024–2026, n = 122). Term infants ≤30 days and preterm infants under term-corrected age hospitalized for acute bronchiolitis were included. RSV status was confirmed by viral testing within 72 h of admission. (3)