Time-Varying Association Between Severe Respiratory Syncytial Virus Infections and Subsequent Severe Asthma and Wheeze and Influences of Age at the Infection.

Background: Early-life severe respiratory syncytial virus (RSV) infection has been associated with subsequent risk of asthma and recurrent wheeze. However, changes in the association over time and the interaction effect of the age at first RSV infection are less well understood. We aimed to assess the time-varying association between RSV and subsequent asthma and wheeze admission and explore how the association was affected by the age at RSV infection.