In a new study, researchers found that infants who were not infected with respiratory syncytial virus (RSV) during their first year of life had a substantial 26% reduced risk of developing childhood asthma at age 5, compared to those who were infected with RSV during infancy. The Infant Susceptibility to Pulmonary Infections and Asthma Following RSV Exposure (INSPIRE) study also estimated that 15% of current asthma cases at age 5 could be prevented by avoiding RSV infection during infancy. The study, published in The Lancet, is the first to specifically test the hypothesis that not being infected with RSV during infancy decreases the risk of childhood asthma. The study enrolled 1946 children born at term in 2012 and 2013, and RSV infection status in the first year of life was ascertained via passive and active surveillance. The study highlights the need for long-term follow-up of common respiratory outcomes among children participating in ongoing and future clinical trials of agents for RSV immunoprophylaxis. While the findings suggest a causal association, the study can never definitively establish causality because of its observational design.
