Bethesda, Dec. 18 (Reuters): An influenza vaccine that can be sprayed painlessly in the nose took a step toward the market as US advisers ruled it was safe and effective for healthy people aged 5 to 49.

But the Food and Drug Administration advisory panel said there was not enough evidence to prove the vaccine, called FluMist and made by MedImmune Inc., works in people aged 50 to 64, a group that health officials urge to get vaccinated against influenza, commonly called the flu.

Millions of Americans each year experience the fever, aches and general misery the flu brings. About 20,000 of them die from the illness, and about 114,000 have to be hospitalised, according to the Centers for Disease Control and Prevention.

Only 30 per cent of healthy US adults, and 10 per cent of healthy US children, get flu shots, the only approved flu immunisations, MedImmune officials said. They hope the easy way of administering FluMist — spraying it into the nose — will persuade more people to become immunised. “It is in this healthy population where we believe FluMist can fill an important public health need,” James Young, MedImmune’s president for research and development, told the panel.

The FDA usually follows its panels’ advice, which means FluMist could be approved and on the market in time for the flu season that starts next fall. But excluding the older age group will restrict FluMist’s sales, some industry analysts said. The vaccine would be co-marketed by Wyeth.

“The majority of flu vaccine users are older people, so it’s bad news the vaccine is not deemed effective for that group,” said Hemant Shah, an independent New Jersey-based analyst.

Shah estimated FluMist will post sales of $50 million to $100 million its first year on the market.