The epidemiology of respiratory syncytial virus (RSV) in hospitalized children in Europe before the widespread implementation of new RSV prophylactic strategies: A systematic review and meta-analysis.

Respiratory syncytial virus (RSV) is a leading cause of pediatric respiratory infections. This systematic review and meta-analysis aims to estimate the in-hospital positivity among children in Europe post-COVID-19 and prior to the implementation of the recent RSV prophylactic strategies. A systematic search was conducted across three databases: PubMed, Scopus and Web of Science from 01/01/2021-31/12/2025. Studies enrolling children aged 0-18 years who were hospitalized with respiratory infection and detected positive for RSV were eligible for inclusion. A random-effect model was applied and heterogeneity was assessed using I2 statistics. Thirty-eight studies met the inclusion criteria, encompasing 66,065 children. The overall pooled RSV in-hospital positivity was 48% (95%CI: 41%-56%). Positivity estimates per year were: 53% (95%CI:49%-56%) for 2021-2022, 49% (95%CI:36%-62%) for 2022-2023, and 62% (95%CI:51%-73%) for 2023-2024 (p = 0.308). RSV positivity in studies with infants (<12-months-old) was 69% vs 30% in studies including older children (0-18 years). Among RSV-positive patients, co-infections were detected in 17%, respiratory support was required in 62% and ICU/NICU admission in 11%. RSV-B predominated over RSV-A during the study period. A substantial burden of RSV-related hospitalizations was detected, especially in infants < 12-months-old; however, the overall pooled positivity estimate should be interpreted with caution. These findings provide an important pre-immunization baseline for evaluating the impact of maternal RSV vaccination and monoclonal antibodies and support the need for continued RSV surveillance across Europe.