Elevated risk of asthma after hospitalization for respiratory syncytial virus infection in infancy.

Severe respiratory syncytial virus (RSV) infection in infancy is associated with substantial morbidity worldwide; whether it is a risk factor for childhood asthma is contentious. A systematic review of 28 articles was conducted, summarizing estimates of asthma risk after RSV hospitalization during infancy. Prevalence estimates of asthma, among those hospitalized for RSV in infancy, were from 8% to 63%, 10% to 92%, and 37%, at ages <5, 5 to 11, and ≥ 12 years, respectively. These rates were higher than those among non-hospitalized comparisons. The attributable risk of asthma due to RSV ranged from 13% to 22% and from 11% to 27% among children aged ≤ 5 and aged 5 to 11, respectively, and was 32% among children ≥ 12 years of age. Overall, 59% of asthma prevalence estimates from those previously hospitalized for RSV exceeded 20%, compared to only 6% of non-hospitalized comparison estimates. Despite variability in asthma prevalence estimates after RSV-related hospitalization, available data suggest a link between severe RSV infection in infancy and childhood asthma.