Inhaled drug may help prevent flu, study says

Zanamivir was found to be most effective if inhaled once a day for four weeks.

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July 7, 1999
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In this story: Doesn't replace vaccine For those at risk Not available yet RELATED STORIES, SITES

(CNN) -- An inhaled medication taken once a day during outbreaks of the flu may help prevent the flu as well as a flu shot, according to a study in the July 7 Journal of the American Medical Association (JAMA).

Researchers found that when the drug, zanamivir, was taken once a day for four weeks it was 67 percent effective in preventing mild cases of the flu (that is, those cases characterized by aches, pains and cough). They also found zanamivir to be 84 percent effective in preventing severe cases of the flu including fever.

The study was funded by Glaxo Wellcome, the drug's maker.

Doesn't replace vaccine

The flu shot is said to be 70 to 90 percent effective in fighting the flu in healthy people. As good as the zanamivir sounds, researchers said it is not intended as a replacement for the flu shot.

"In prevention, we see zanamivir as an adjunct or an addition to use of vaccine to be used in certain circumstances where people want prevention for a short period of time, in families or in the workplace after people are exposed to individuals with the flu," Dr. Arnold Monto of the University of Michigan said.

The study, conducted at the University of Michigan School of Public Health in Ann Arbor, included 1,107 healthy adults from Ann Arbor, Michigan, and Columbia, Missouri. The participants were studied during local flu outbreaks. Half the group received a placebo, and half inhaled 10 milligrams of zanamivir once a day for four weeks.

There are some concerns that patients would not be willing to take zanamivir, an anti-viral medication, for four weeks straight.

"You have to remember to do it, but I don't think it's so difficult that it would really be a deterrent. It's so easy to do, it's easier than brushing your teeth in the morning. It's quick and simple," said study participant Chris Victor.

For those at risk

Researchers say zanamivir has no side effects.

That's important because until vaccines are available year-round, those at high risk of complications from the flu -- the elderly and those with weakened immune systems -- may be relying on anti-virals like zanamivir. Earlier anti-flu drugs, amantadine and rimantadine, raised concerns about adverse effects, the study's authors wrote.

Also, for the second summer in a row, Alaska and Canada's Yukon Territory have experienced flu outbreaks that threaten summer tourists who don't have access to flu shots.

"What's we're seeing really is a change in the seasonality and the pattern of influenza and the need to be prepared in the off-season for flu and physicians to be prepared to diagnose flu in the summertime when they are not accustomed to looking for it," said Dr. Martin Cetron, Centers for Disease Control and Prevention.

Not available yet

Other studies have shown zanamivir to be effective in reducing the duration and severity of a flu infection.

Zanamivir is not available in the United States. A Food and Drug Administration advisory committee recommended against approving the drug in February. The group felt the drug was not effective enough. Glaxo Wellcome is still trying to get zanamivir approved.