The Journal of asthma : official journal of the Association for the Care of Asthma
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Common upper respiratory tract viruses are the most frequent and important causes of asthma exacerbations in both children and adults. Prospective epidemiologic studies report that up to 80% of childhood exacerbations are associated with viral upper respiratory tract infections. ⋯ Although viral upper respiratory tract infections are the most common cause of asthma exacerbations, the severity level of the exacerbation seems to be independent of whether a respiratory virus has been detected.