Background

Wheezy episodes in young children are often triggered by viral and bacterial respiratory tract infections, but there is little evidence supporting the hypothesis that symptom duration depends on the specific microbial trigger.

Objective

We sought to investigate whether the duration of wheezy episodes in young children depends on the microbial trigger.

Methods

Two hundred eighty-three children from the Copenhagen Prospective Study on Asthma in Childhood2000 at-risk birth cohort were prospectively examined for common airway pathogenic bacteria and viruses during acute wheezy episodes in the first 3 years of life. Findings were related to symptomatic duration of episodes, as monitored in daily diary cards from birth.

Results

Eight hundred thirty-seven samples were investigated for viruses, bacteria, or both. Both viruses and bacteria were identified in 55% of episodes, bacteria were identified exclusively in 31% of episodes, and viruses were identified exclusively in 10% of episodes. The median duration of acute symptoms was 9 days (interquartile range, 5-16 days), and duration was independent of bacterial or viral species.

Conclusions

The duration of wheezy episodes was independent of pathogenic airway bacterial or viral species. This suggests that symptom burden from infections is dependent on other factors, such as environmental exposures or host factors. The common term viral wheeze seems inappropriate in view of the finding of pathogenic bacteria in 86% of wheezy episodes.