An experimental drug inhaled once a day for treatment of the flu also can prevent it, according to a study in Wednesday's Journal of the American Medical Association.
Relenza, generically known as Zanamavir, is a drug that is inhaled through the mouth using an inhaler device, reports CBS News Health Correspondent Dr. Emily Senay. The drug fights the flu by preventing the spread of the virus in the respiratory tract. The latest study shows that if inhaled once a day at the start of the flu season, its virus-fighting properties can also prevent illness as well.
People who took the drug were 67 percent less likely to develop flu symptoms, and 84 percent less likely to get a serious case of flu with a fever.
The study followed 1,107 students at the University of Michigan and the University of Missouri during the 1997 flu season. They kept diaries to note any flu symptoms and rate their severity.
The study's numbers are small because that flu season was a relatively mild one. Only 34 of 554 people assigned to receive a placebo came down with flu compared with 11 of 553 people who took Relenza.
The most common side effects were headache, nasal symptoms, sore throat, coughing and fatigue.
The drug also was effective in preventing several strains of Type A influenza and previous studies have shown the drug to be able to fight Type B as well.
The leader of the study, University of Michigan epidemiologist Dr. Arnold Monto, said current flu vaccines remain the best defense against the flu, but they require two to four weeks to take effect after getting the shot.
The flu vaccine is especially helpful for the elderly or young children who are at high-risk for the virus.
Relenza, made by GlaxoWellcome Inc. and available in Europe, is awaiting approval for sale as a flu treatment in the United States. A Food and Drug Administration committee has asked for more proof about the drug's effectiveness and questioned whether consumers could use inhalers.
An editorial accompanying the JAMA report raised the same issue, saying that without careful supervision, it "could prove befuddling to the first-time user."
Its manufacturers hope it will be available by prescription this coming flu season.