Preventive strategies for respiratory syncytial virus infection and their impact on bronchiolitis incidence and severity in infants: a systematic review

Abstract

Introduction: Acute bronchiolitis is the leading cause of lower respiratory tract infection in infants, with respiratory syncytial virus (RSV) being the most frequent etiological agent and strongly associated with severe clinical outcomes. In the absence of effective specific therapies, preventive strategies have become central to reducing the disease burden. Objective: To evaluate preventive strategies against respiratory syncytial virus infection and their impact on the incidence and severity of bronchiolitis in infants. Methods: This is a systematic review conducted in accordance with PRISMA 2020 guidelines. A comprehensive search was performed in MEDLINE/PubMed, Scopus, Web of Science, Cochrane Library, SciELO, and BVS/LILACS databases, using controlled descriptors (MeSH/DeCS) and free-text terms related to RSV, bronchiolitis, infants, and prevention. Clinical trials, cohort studies, and observational studies evaluating preventive strategies and relevant clinical outcomes were included. Study selection was performed independently by two reviewers, followed by standardized data extraction and methodological quality assessment. Results: Six studies were included in the final analysis. Evidence demonstrated that long-acting monoclonal antibodies, such as nirsevimab, showed high efficacy in reducing RSV-associated lower respiratory tract infections and hospitalizations. Maternal vaccination significantly reduced severe disease in early infancy. Palivizumab remained effective in high-risk populations, although its implementation is limited by operational constraints. Non-pharmacological measures, particularly breastfeeding, were associated with reduced disease severity. Heterogeneity among studies was observed regarding design, populations, and outcome definitions. Conclusion: Preventive strategies against RSV show significant potential in reducing the burden of bronchiolitis in infants, particularly long-acting immunoprophylaxis and maternal vaccination. Integrated approaches tailored to clinical and epidemiological contexts may optimize health outcomes and resource utilization. Furthermore, incorporating these strategies into public health policies may expand preventive coverage and reduce disparities in child health across different socioeconomic and healthcare settings.