FRIDAY, Feb. 20, 2004 (HealthDayNews) -- A new Dutch study suggests that while parents with asthmatic children need not worry that the flu vaccine might trigger asthma attacks, the shots don't protect against them either.
The issue has been controversial, since previous studies have produced conflicting results on the topic: Some have suggested flu shots have a protective effect on asthma attacks, while others have claimed the shots can trigger attacks.
"Yes, there have been worries and hopes -- on the one side, worries that it might trigger an attack, and the hope was that perhaps it might actually prevent exacerbation," says Dr. Frank DeStefano, a researcher with the U.S. Centers for Disease Control and Prevention's National Immunization Program.
"But I think it's clear that the flu shot doesn't have impact, but that's not the reason to recommend flu shots," DeStefano adds. "They are to prevent flu infections and complications that those might cause in high-risk groups, and children with asthma are in a high-risk group."
Study author Dr. Herman J. Bueving, of Erasmus University Medical Center in Rotterdam, stands behind his group's findings: "I would maybe like to see more studies like this to reinforce these (findings), but I think that we will see that influenza vaccines don't have any real effect on asthma exacerbation."
In this latest report, Bueving and his colleagues studied almost 700 children with asthma between the ages of 6 and 18, 347 of whom were given the flu vaccine and 349 who were given placebo. They found that flu shots did not significantly reduce the number, severity or duration of flu-related asthma attacks.
Bueving also notes the vaccines used in the seasons studied were very effective.
"For the two seasons of this study we had good matches with the type of flu and vaccine, and that is important," he adds. "Otherwise it can be said, 'Well, if you don't have a good match, you were just lucky with your results.'"
At the beginning of each flu season, which occurs from October to April, the World Health Organization issues guidelines on the probable strain of flu for the coming season. This often lets countries prepare and stock the best vaccine for that season, although a particular strain may not surface until after the vaccine is produced.
For parents trying to decide what is best for their asthmatic child, a recent American Lung Association (ALA) study put some fears to rest by finding that flu shots don't increase the risk of asthma attacks. The ALA currently recommends that "high-risk" groups, such as infants from 6 months to 23 months and children aged 5 and up, including those with asthma, get flu shots.
According to the ALA, an estimated 8.6 million Americans under the age of 18 have been diagnosed with asthma in their lifetime, and 3.8 million had an asthma attack or episode in the past year.
Asthma is a lifelong condition in which sufferers have overly sensitive air passageways in their lungs that can constrict, due to a number of different factors, and limit air flow to the body. Once triggered, attacks can be sudden and can range from mild to life-threatening.
The Dutch study appears in the current issue of the Journal of Respiratory and Critical Care Medicine.
More information
The National Heart, Lung, and Blood Institute has more on asthma, while the National Vaccine Information Center has more on vaccines.
