Objective. Influenza is known to aggravate asthma; however, the effectiveness of the influenza vaccine in preventing influenza-related asthma is not known.
Study Population. Children 1 through 6 years old with asthma from 4 large health maintenance organizations.
Methods. This was a population-based, retrospective cohort study that used medical and vaccination records from 4 large health maintenance organizations within the United States during the 1993–1994, 1994–1995, and mid-1995–1996 influenza seasons. Children with asthma were identified by searching computerized databases of medical encounters and pharmacy records. The main outcome measures were exacerbations of asthma that were treated in the emergency room or hospital.
Results. Unadjusted rates of asthma episodes were higher after influenza vaccination than before vaccination. However, after adjusting for asthma severity, the incidence rate ratios of asthma exacerbations after vaccination were 078, 0.59, and 0.65 compared with the period before vaccination during the 3 respective influenza seasons.
Conclusion. After controlling for asthma severity, the authors found that influenza vaccination protects against acute asthma exacerbations in children.
Reviewer’s Comments. This is a useful study in that it supports the recommendation to provide influenza vaccinations to children with asthma, especially for those children with more severe asthma. Although other viruses clearly cause more asthma exacerbations than influenza, at least this one can be prevented. Additional prospective studies in larger populations to confirm these results would be very helpful.
- Copyright © 2002 by the American Academy of Pediatrics