Background: Candidate respiratory syncytial virus (RSV) vaccine trials in pregnant women and infants are underway and a greater understanding of RSV epidemiology is now needed, especially in paediatric populations with high rates of acute and chronic respiratory disease. Our study aimed to identify RSV prevalence in children living in northern Australia, a region with a high respiratory disease burden.

Methods: Eleven prospective studies (four hospital- and seven community-based) of infants and children with acute and chronic respiratory illnesses, as well as otitis media, were conducted between 1996-2017 inclusive. The data for these trials were extracted and where available their nasopharyngeal swabs biobanked at -80°C were tested by polymerase chain reaction assays for RSV, 16 other viruses and atypical respiratory bacterial pathogens.

Results: Of 1127 children included, the median age was 1.8-years (IQR 0.5-4.9); 58% were male, and 90% Indigenous. After human rhinoviruses (HRV), RSV was the second most prevalent virus (15%, 95%CI 13-18). RSV prevalence was greatest amongst children aged <2-years hospitalised with bronchiolitis (47%; 95%CI 41.4-52.4), where almost one-third were aged >6-months. In contrast, RSV prevalence was only 1-3.5% in other age groups and settings. In one-third of RSV cases, another respiratory virus was also detected. Individual viruses other than RSV and HRV were uncommon (0-9%).

Conclusion: In northern Australia, effective maternal and infant RSV vaccines could substantially reduce RSV bronchiolitis-related hospitalisations, including admissions of Indigenous infants.