GAITHERSBURG, Md. (AP) _ A long-anticipated flu vaccine _ one squirted up people's noses instead of injected into their arms _ faces a big hurdle as government scientists debate its safety.
Aviron Inc.'s FluMist isn't just a new way to give flu vaccine. It is made with live flu virus instead of the killed virus in today's flu shots.
So advisers to the Food and Drug Administration are taking a hard look at studies of more 24,000 people as they decide whether FluMist could be a safe way to protect Americans, including very young children, from influenza.
Even if the panel votes Friday to back FluMist, and if the FDA ultimately approves the vaccine, it would not be for everyone. Aviron hopes initially to sell FluMist for healthy people, from 1-year-old toddlers up to 64-year-old adults. No one yet knows if it is safe for the elderly and people with asthma or other illnesses, those most at risk for complications from the flu. Studies in those groups are under way.
A painless flu vaccine could persuade more Americans to get the annual protection. About 70 million get today's flu vaccine, a shot in the arm, each year. Yet influenza still kills 20,000 Americans each year and hospitalizes about 100,000.
The nasal vaccine stimulates the immune system through the same nose tissue where the flu virus attacks. But no direct comparison of nasal versus injected vaccines has been done to prove if one type is any better than the other.
In Aviron's main study of children, 1,600 healthy youngsters _ ages 15 months to 6 years _ had either FluMist or a dummy nasal spray squirted up each nostril. Children who later got sick were tested for influenza.
FluMist proved 93 percent effective in preventing the flu.
The main study of FluMist in adults did not prove quite as promising. Some 4,561 healthy, working adults ages 18 to 64 were given either FluMist or a dummy spray, and then reported any symptoms to researchers.
FluMist recipients were just as likely as the nonvaccinated to experience a flulike illness during the winter's peak influenza period. However, vaccination did cut severe illness by 19 percent, as well as cutting lost days of work and doctor visits.
The FDA's advisory panel will weigh those and other studies before voting on whether FluMist is safe and effective. The FDA is not bound by its advisers' recommendations but typically follow them, and is expected to decide FluMist's fate by early fall. How quickly a decision comes will determine whether Aviron could supply a limited amount of vaccine in time for this year's flu season.