Background: Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection (ALRI) in early life, and severe infection may increase the risk of childhood asthma. The effect of age at RSV hospitalization is not well understood. We aimed to assess the association between RSV hospitalization before age 2 and subsequent childhood asthma, and how this association was affected by age at severe infection. Methods: We conducted a population-based retrospective cohort study of children born in 2017–2018 in Suzhou, China. Participants were classified into 3 groups based on hospitalization for ALRI and RSV testing before age 2: RSV-positive hospitalization, RSV-negative hospitalization and population controls without hospitalization. The incidence of asthma and recurrent wheeze before age 6 was compared across groups. Poisson regression with robust variance estimation was used to estimate adjusted risk ratios, and stratified analyses assessed the effect of age at severe RSV infection. Results: We observed children with RSV-positive ALRI hospitalization before age 2 had approximately a 2-fold higher risk of asthma and a 2.6-fold higher risk of recurrent wheeze than matched controls, but the associations waned and were no longer significant after 4 years. The highest risk of asthma occurred in children hospitalized between 12 and <24 months, while the greatest risk of recurrent wheeze was observed between 6 and <12 months. Conclusions: Hospitalization for RSV-ALRI in the first 2 years, especially between 12 and <24 months, was associated with an increased risk of childhood asthma, providing new evidence for RSV prevention strategies.
Shen et al. (Wed,) studied this question.