Epidemiology of respiratory syncytial virus in a community birth cohort of infants in the first 2 years of life

Abstract

espiratory syncytial virus (RSV) is the most common virus identified in children hospitalised with acute respiratory infections. However, less is known about RSV in community settings. This report describes RSV epidemiology in the community, including acute illness episodes, healthcare burden, and risk factors in Australian children during the first 2-years of life. A community-based, birth cohort from Brisbane, Australia, followed children until their second birthday. Parents completed daily respiratory symptom and illness-burden diaries. Weekly parent-collected nasal swabs were analysed for RSV by real-time polymerase chain reaction assays. Serum RSV-neutralising antibodies were assayed at age 3 years. Overall, 158 children provided 11,216 swabs, of which 104 were RSV-positive (85 incident episodes). RSV incidence in the first 2 years of life was 0.46 (95% CI = 0.37–0.58) episodes per child-year. Incidence increased with age and formal childcare attendance and was highest in autumn. Of 82 episodes linked with symptom data, 60 (73.2%) were symptomatic, 28 (34.1%) received community-based medical care, and 2 (2.4%) led to hospitalisation. Viral load was higher in symptomatic than asymptomatic infections. In 72 children, RSV-specific antibody seroprevalence was 94.4% at age 3 years.

Conclusion: RSV incidence increased after age 6-months with approximately three-quarters of infections symptomatic and most infections treated in the community.