One of the major questions regarding long-term side effects of bronchiolitis by respiratory syncytial virus (RSV) is whether or not it induces asthma in later life. In this quantitative review, the data of 10 controlled studies are analysed.
Methods: Follow-up studies of RSV bronchiolitis published between January 1978 and December 1998 were identified through a MEDLINE search. Studies were selected if (i) postnatal age at the time of the initial illness was below 12 mo, (ii) all children were hospitalized for RSV bronchiolitis, (iii) the diagnosis RSV was virologically confirmed in all cases, and (iv) a control group was used.
Results: Six studies met all selection criteria. Up to 5 y of follow-up after RSV bronchiolitis in infancy, 40% of children reported wheezing as compared to only 11% in the control group (p <0.001). Between 5 and 10 y of follow-up 22% of the bronchiolitis group reported wheezing against 10% of the control group (p = 0.19). The incidence of recurrent wheezing as defined by three or more wheezing episodes also decreased with increasing years of follow-up: at 5 or more years of follow-up the difference between the RSV group and the control group was no longer significant. Furthermore, the presence of either a personal and/or a family history of either atopy and/or asthma did not differ between the two groups.
Conclusions: Wheezing is common after RSV bronchiolitis in infancy. It may persist for > or = 5 y of follow-up. However, no significant difference between the RSV bronchiolitis and the control group was observed regarding recurrent wheezing by 5 y of follow-up. No significant difference between the RSV bronchiolitis and the control group were found regarding a personal history of atopy, a family history of atopy and/or asthma. Therefore it seems unlikely that RSV bronchiolitis is a cause of atopic asthma in later life.