CHICAGO — If a deadly bird flu should spread quickly around the world, Americans could find themselves at the back of the line for any new vaccine developed to combat it.

There are few U.S. vaccine makers. And even those, such as Deerfield, Ill.-based Baxter International, produce most of their flu vaccine outside the United States in countries that can claim first dibs on any vaccine made to protect against bird flu, the company and government officials acknowledged.

While U.S. health officials and vaccine makers would like to think goodwill would take precedence at the outbreak of a fast-spreading bird-flu pandemic, the void in U.S.-based production capacity for vaccines could create a major problem if a vaccine became available.

"If there is an epidemic of bird flu and people start dying in the proportion people believe, I don't think goodwill is going to be an issue," said Dr. Robert Daum, head of the pediatric infectious-diseases program at the University of Chicago and former chairman of the Food and Drug Administration's (FDA) vaccine-advisory committee. "It's going to be every man for himself."

Scientists fear that if the H5N1 strain of the bird-flu virus, which has killed more than 60 people in Asia since it first appeared in 1997, passes from birds to humans on a large scale, it could mutate into a variety that could spread easily among humans. In a virulent form, they say, this could kill millions worldwide.

There is no commercially available bird-flu vaccine, and no one knows for certain how much of the experimental vaccines being worked on would be available and when. But if one is developed, the void in capacity to produce flu vaccines in the United States highlights the troubling aspects of the U.S. vaccine business, which has unappealing economics: small profits, high risks and stagnant innovation.

The Bush administration this month met with six major vaccine makers to spur more interest in flu-vaccine production. A White House spokesman said the administration soon will release "a pandemic flu plan" that is expected to address the critical issue of U.S. flu-vaccine manufacturing capacity. But administration officials are aware they have a major problem on their hands.

"There's no secret about the fact that our vaccine-manufacturing capacity domestically is not what we need it to be," U.S. Secretary of Health and Human Services Mike Leavitt said after a meeting this month with vaccine makers.

Although there is no human vaccine for the current strain of bird flu, scientists believe Tamiflu, an anti-viral, may help humans fend off the virus.

Tamiflu's Swiss manufacturer, Roche, said yesterday it will build a plant in the United States to boost production of the drug. Roche did not disclose the location.

Demand for Tamiflu is far outstripping Roche's ability to make it. By the middle of next year, the company says, it will have boosted production tenfold since 2003.

Also yesterday, India's Cipla, which said last week it had developed a generic version of Tamiflu, plans to approach Roche for a license soon, Joint Managing Director Amar Lulla said.

Roche has been under growing pressure from governments and U.N. Secretary-General Kofi Annan to license generic versions of Tamiflu.

Sen. Charles Schumer, D-N.Y., will call on Roche to license Tamiflu production to five U.S. companies within 30 days, he said yesterday.

While Roche has ruled out relinquishing the patent on the drug, which is protected until 2016, it also has said it was seeking other companies to help speed production caused by the increased demand.

Material from The Associated Press is included in this report.