Association of Age at First Severe Respiratory Syncytial Virus Disease With Subsequent Risk of Severe Asthma: A Population-Based Cohort Study

Abstract

Abstract Objective In a population-based cohort study, we determined the association between the age at first severe respiratory syncytial virus (RSV) disease and subsequent asthma. Methods Incidence rates and rate ratios of the first asthma-associated hospitalization after 2 years of age in children hospitalized for RSV disease at <3 months, 3 to <6 months, 6 to <12 months, and 12–24 months of age were calculated. Results The incidence of asthma-associated hospitalization per 1000 child-years among children hospitalized for RSV disease at <3 months of age was 0.5 (95% confidence interval [CI], .2–.7); at 3 to <6 months of age, 0.9 (95% CI,.5–1.3); at 6 to <12 months of age, 2.0 (95% CI, 1.4–2.7); and at 12–24 months of age, 1.7 (95% CI, 1.0–2.5). The rate ratio of hospitalization for asthma was 2–7-fold greater among children hospitalized for RSV disease at ages ≥6 months than that among those hospitalized for RSV disease at ages 0 to <6 months. Conclusions Although the burden of RSV disease is highest in children aged <6 months, the burden of subsequent asthma is higher in children who develop RSV disease at ages ≥6 months.