Preschool asthma after bronchiolitis in infancy.

Asthma risk is lower after wheezing associated with respiratory syncytial virus (RSV) than with non-RSV infection in infancy. RSV is the main wheezing-associated virus in infants aged <6 months. We evaluated the outcome of children hospitalised for bronchiolitis at <6 months of age, with special focus on viral aetiology and early risk factors. Out of 205 infants hospitalised for bronchiolitis at <6 months of age, 127 (62%) attended a control visit at a mean age of 6.5 yrs and the parents of an additional 39 children were interviewed by telephone. Thus, follow-up data collected by identical structured questionnaires were available from 166 (81%) children. Viral aetiology of bronchiolitis, studied on admission by antigen detection or PCR, was demonstrable in 97% of cases. Current asthma was present in 21 (12.7%) children: 8.2% in the 110 former RSV patients versus 24% in non-RSV patients (p=0.01). 45 (27%) children had ever had asthma. In adjusted analyses, atopic dermatitis, non-RSV bronchiolitis and maternal asthma were independently significant early-life risk factors for asthma. The risk of asthma was lower after RSV bronchiolitis than after bronchiolitis caused by other viruses in children hospitalised at <6 months of age.