WESTPORT, Jul 20 (Reuters Health) - A large, population-based observational study indicates that influenza vaccination does not cause acute exacerbation in asthmatic children, researchers report in the July issue of the Archives of Family Medicine.

Dr. Piotr Kramarz, of the Centers for Disease Control and Prevention in Atlanta, Georgia, and members of the Vaccine Safety Datalink Team, examined records of asthma hospitalizations and emergency room visits after influenza vaccination of asthmatic children who were members of four health maintenance organizations.

More than 131,000 asthmatic children ages 1 to 6 years were involved in the study which covered three influenza seasons ending in 1996.

After controlling for asthma severity, vaccination was not associated with acute asthma exacerbation within a 2-week period. In fact, there was a decrease in the risk of exacerbation following vaccination in all three studied seasons. This reached statistical significance for 1993 to 1994, and the researchers are looking into the possibility that vaccination may be protective against exacerbation.

"Concern about possible exacerbation of asthma," they conclude, "is not a valid reason to not vaccinate children with asthma against influenza."

Arch Fam Med 2000;9:617-623.