Background: The rhinovirus etiology of wheezing is an important risk factor for developing recurrent wheezing and asthma, especially in children with atopic predisposition. However, rhinovirus infection has not yet been included in the risk assessment of different asthma phenotypes at school-age.

Aims: To study 1) the impact of known risk factors and rhinovirus etiology of the first severe virus-induced wheezing episode for developing persistent asthma; 2) risk factors for developing atopic and non-atopic asthma at school-age; and 3) whether prednisolone treatment of the first wheezing episode may prevent development of asthma symptoms.

Methods: Risk factors for asthma symptoms were studied in a 7-year follow-up of Vinku study (n=111, median age 12 months at the first wheezing). Risk factors for atopic and non-atopic school-age asthma were studied in steroid-naive children jointly in Vinku and Vinku2 studies (n=127; 11 months, respectively). The preventive effect of prednisolone was assessed in two randomized trials; post hoc in Vinku study and prospectively in Vinku2 study.

Results: Early-onset food sensitization and rhinovirus etiology of the first wheezing episode predicted persistent asthma symptoms, and development of atopic asthma at school-age. Parental smoking and age <12 months predicted non-atopic asthma at school-age. The children with rhinovirus-induced first wheezing in the Vinku study, and those with high rhinoviral load in the Vinku2 study benefitted from prednisolone in terms of less persistent asthma symptoms.

Conclusions: Virus etiology and atopic status are worth assessing in wheezing children to recognize those with increased asthma risk. The separate risk factors of asthma phenotypes suggest different mechanisms underlying atopic and non-atopic asthma in children. This knowledge could provide a mean to identify children who would benefit from early anti-inflammatory treatment to prevent asthma.