Understanding the local-level variations in seasonality of human respiratory syncytial virus infection: a systematic analysis.

Summary

Synthesizing 7 studies plus 3 national datasets (Japan, Spain, Scotland; 888,447 cases), this analysis shows local-level RSV season onset can vary by ~6 weeks and offset by ~5 weeks within regions. Meteorological, geographical, and sociodemographic factors jointly explain a large share of onset and offset variability, informing local immunization and resource planning.

Key Findings

• Across 101 local sites (1995–2020; 888,447 cases), RSV season onset varied by ~6 weeks and offset by ~5 weeks within regions.
• Temperature, humidity, wind, latitude/longitude, income, and population jointly explained 66–84% of onset and 35–49% of offset variability.
• Year-to-year differences were substantial, emphasizing the need for adaptive, local-level planning.

Clinical Implications

Supports tailoring timing of nirsevimab/palivizumab and vaccination strategies by locality, using meteorological and demographic data to anticipate RSV onset and optimize resource allocation.

Limitations

• Heterogeneity in surveillance definitions and data quality across sites and years
• Explained variability lower for season offset (35–49%), indicating unmeasured drivers

Future Directions

Develop real-time local predictive models integrating weather feeds to guide immunization scheduling; evaluate impact of tailored timing on RSV hospitalizations and health-system load.