Industry incentives may help ensure flu vaccine supply.(News)

With the United States facing an influenza vaccine shortage this season, vaccine experts are calling for long-term solutions to ensure adequate supplies in the future.

"It's such a fragile supply system and such an unpredictable demand that any little thing can throw it out of orbit," commented Gregory Poland, M.D., who is the director of the Mayo Vaccine Research Group at the Mayo Clinic, Rochester, Minn.

This season, health officials in the United States had expected to have about 100 million doses of the flu vaccine on hand, but manufacturing problems at one company's facility has blocked access to almost half of the expected doses and left only one manufacturer to produce the vaccine.

As U.S. health officials urge health care providers to channel vaccines only to those individuals who are at the greatest risk of developing complications from the flu--mainly young children and the elderly--experts are examining why manufacturers are reluctant to make vaccines and how to entice more companies into the field.

Manufacturers are leaving the market because they don't see it as profitable, Julie Gerberding, M.D., who is the director of the Centers for Disease Control and Prevention, said at a recent press conference on this year's flu vaccine shortage.

Companies are also reluctant to take on the complex process of making these vaccines, she said.

"These are biologics and we use them for healthy people so the risks are very high," Dr. Gerberding said. "Anytime you're offering something to someone who is a completely healthy person, the balance between risks and benefits looms large."