Respiratory Syncytial Virus Disease Burden and Evidence Gaps in Australia Before Immunisation Introduction: A Retrospective Population-Based Study Using 2016-2019 Hospitalisation and 2023 Laboratory Surveillance Data.

This study evaluated Australia's national respiratory syncytial virus (RSV) burden and highlighted key data gaps. Hospitalisations (2016-2019) peaked in infants aged < 3 months (4014/100,000) and adults aged ≥ 65 years (122/100,000), nearly doubling over the period. Unspecified causes comprised ≈55% of bronchiolitis hospitalisations in children aged < 24 months. Laboratory notifications (2023) peaked at 6-11 months (7778/100,000). Real-time data integration addressing case-ascertainment and diagnostic testing frequency is essential for accurate burden estimates and future immunisation strategies.