Enhanced respiratory syncytial virus surveillance of young children admitted to the Sydney Children’s Hospitals Network, 2019–2023

ObjectivesIn this study, we aimed to comprehensively describe the clinical characteristics, management and outcomes of children with respiratory syncytial virus (RSV) disease admitted to the Sydney Children’s Hospitals Network (SCHN), determine the full burden of severe disease and identify population-specific risk factors for intensive care unit (ICU) admission.Study typeMulti-centre, retrospective cohort study conducted over 5 years.MethodsThe study was conducted at two tertiary paediatric hospitals in metropolitan New South Wales, Australia, before implementation of government-funded immunisation programs against RSV in children. Participants were children aged <2 years hospitalised with laboratory-confirmed RSV from 1 January 2019 to 31 December 2023, comprising all ICU admitted, and a random sample of non-ICU admitted patients. The main outcome measures were characteristics and incidence rate of RSV hospitalisations and ICU admissions among children aged <2 years.ResultsOver a 5-year period, 4414 children were hospitalised with laboratory-confirmed RSV, of whom 11.3% (499/4414) were admitted to ICU. The median age was younger in the ICU cohort (n = 499) compared with the non-ICU sample (n = 1000; 3.3 vs 7.1 months, P < 0.0001). Factors associated with higher odds of ICU admission in multivariate logistic regression were decreasing month of age (OR 1.10, 95% CI 1.06–1.11), prematurity (OR 2.17, 95% CI 1.61–2.91), Indigenous identity (OR 4.10, 95% CI 2.30–7.56) and cardiac disease (OR 3.39, 95% CI 2.06–5.70). The average hospitalisation incidence rate was 1615 per 100,000 (95% CI 1565–1666), with higher rates among children aged <1 year, 2141 per 100,000 (95% CI 2061–2224) compared with those aged 1–2 years, 1088 per 100,000 (95% CI 1030–1148).ConclusionsRSV immunisation programs are expected to substantially reduce the burden of hospitalisation among Australian children in their first year of life. Children who are Indigenous, were born prematurely or have heart disease are at greatest risk of severe disease and may benefit from extended preventative programs.