In the INSPIRE trial, avoidance of severe respiratory syncytial virus (RSV) infection in the first year of life of healthy, full-term infants was associated with age-dependent reduced risk of childhood asthma, researchers report. “To definitively establish causality, the effect of interventions that prevent, delay, or decrease the severity of the initial RSV infection on childhood asthma will need to be studied,” the authors conclude.
The population-based study was initiated at 11 pediatric practices in middle Tennessee for children born between June and Dec. 2012 or June and Dec. 2013. Passive and active surveillance identified children with or without RSV infections in infancy. During prospective monitoring of the participants, the primary outcome of 5-year current asthma showed these patterns: “Of 1,946 eligible children who were enrolled in the study, 1,741 (89%) had available data to assess RSV infection status in the first year of life. The proportion of children with RSV infection during infancy was 944 (54%; 95% CI 52–57) of 1,741 children. The proportion of children with 5-year current asthma was lower among those without RSV infection during infancy (91 [16%] of 587) than those with RSV infection during infancy (139 [21%] of 670; P = 0.016). Not being infected with RSV during infancy was associated with a 26% lower risk of 5-year current asthma than being infected with RSV during infancy (adjusted RR 0.74, 95% CI 0.58–0.94, P = 0.014). The estimated proportion of 5-year current asthma cases that could be prevented by avoiding RSV infection during infancy was 15% (95% CI 2.2–26.8).”