Burden and Characteristics of Respiratory Syncytial Virus‐Associated Bronchiolitis in Hospitalized Infants in Italy: A Systematic Review

Background: Respiratory syncytial virus (RSV) is the main cause of bronchiolitis in infants. This systematic review aimed to evaluate the burden of RSV-associated bronchiolitis among hospitalized Italian infants between 2000 and 2023. Methods: A comprehensive literature search identified studies examining RSV-related hospitalizations for bronchiolitis in children aged 0–59 months. Eligible studies met the following criteria: conducted in Italy, focused on children, reported on RSV prevalence, co-infections, genotype distribution (RSV-A, RSV-B), and seasonal trends, and published in English or Italian. Data extraction focused on study design, infant characteristics (e.g., age, preterm birth), and RSV detection methods. Results: Twenty-four studies were included. Infants under 12 months were most affected. RSV was the primary pathogen identified, though co-infections with other respiratory viruses, such as human rhinovirus, were common. RSV infections typically peaked in late autumn and winter, but the COVID-19 pandemic altered these patterns. This review highlights the significant burden of RSV-associated bronchiolitis in Italian infants. While RSV remains the primary pathogen, co-infections and pandemic related factors have altered its epidemiological trends. Conclusions: Nationwide RSV immunization programmes and improved diagnostics are crucial to ease the strain on pediatric intensive care units. Recent recommendations for widespread RSV long-acting monoclonal antibody use in infants offer promising solutions to address this challenge.