The Epidemiology of Respiratory Syncytial Virus Lower Respiratory Tract Infection on Young Children

Reply: We thank Cooper et al for their comments. We concur with the authors that, in our study, the rate of respiratory syncytial virus (RSV) acute lower respiratory tract infection (LRI) in infants <6 months of age is not low (50/1000 child years)1 and also agree that when examined, globally, the rates of RSV LRI during the first 6 months of life are not low either (2, Supplementary Figures 1–3). It has been estimated that globally RSV causes 33.8 (95% confidence interval 19.3–46.2) million episodes of RSV-associated LRI in children <5 years of age, two-third occurring in the first year of life with a substantial proportion in those <6 months of age.2 In a recent report from the United States,…