Influenza Virus and Acute Asthma in Children

Abstract

To the Editor.—Miller et al1 reported the burden of influenza-attributable health care utilization to be high among children with asthma. The reason for this, however, remained unanswered. The authors speculated that children with a history of asthma could be (1) more likely to have severe illness with influenza infections or (2) just be more likely to seek medical care for upper respiratory infection (or be hospitalized) than healthy children with the same clinical presentation because of concern of asthma exacerbation. First, because their enrollment criteria were upper respiratory infection or fever, and exacerbation of asthma was not ascertained from the medical charts, we emphasize that there is no proof in their article, or in the literature, that influenza virus infection is a major trigger of airway hyperreactivity or exacerbation of asthma in children.2–4 The authors correctly avoided claiming this. In fact, influenza virus has been one of the least prevalent viral findings in wheezing children. Furthermore, the data on the efficacy of the vaccination in preventing influenza virus induced asthma exacerbations is anecdotal in children.5–8 Second, we think that it is important to investigate reasons for this influenza-attributable health care utilization in asthmatic children. Regardless of whether it is just a false concern by the parents and physicians that influenza virus infection is a major trigger of asthma exacerbations, there is an important educational aim. Taken together, the burden of influenza is inevitably high among young children, and all young children, rather than just those who are asthmatic, are likely to benefit from influenza vaccination.9,10