US Vaccine Supply Could Be Limited in Flu Pandemic

Most influenza vaccines for Americans are manufactured in other countries—a scenario that could limit U.S. supplies should a swine flu vaccine be needed in the coming months.

U.S. government officials have taken steps in recent years to promote more production on U.S. soil by a diverse group of companies, but those efforts are far from complete.

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If the current strain of swine flu turned into a pandemic, some health experts worry countries might try to reserve flu vaccine for their own citizens.

"If this thing goes global, our lack of capacity makes it very hard," said former U.S. Health and Human Services Deputy Secretary Tevi Troy, who worked on flu preparedness efforts in the George W. Bush administration.

"One of the things we were worried about is what if European governments say 'Hey, I know you've got a contract with the U.S. government, but we're going to nationalize our capacity.' That is a concern," said Troy, now a visiting senior fellow at the Hudson Institute.

But other experts say U.S. capacity has greatly improved in recent years.

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Global health officials are debating whether to ask manufacturers to mass-produce a vaccine to fight the H1N1 strain of swine flu that has killed dozens of people in Mexico plus a Mexican boy who was brought to the United States for treatment.

Infections have been found in the United States, New Zealand, Israel, Canada and Spain.

Months to Make

Manufacturers have taken initial steps, but it would require months to make a vaccine to fight the new strain.

An immunization against a pandemic virus "will probably be the most highly sought-after product on the face of the earth," said Mike Osterholm, director of the Minnesota-based Center for Infectious Disease Research and Policy.

"In the face of a pandemic, it's hard to imagine any country willingly letting vaccine leave from within its border to another country just because there's a contract" with the U.S. government, he said.

The precarious situation was highlighted in 2004 when a British flu vaccine plant was contaminated, wiping out half the U.S. supply for that year.

The Bush administration in 2006 gave $1 billion to five companies to modernize production of vaccines and make them in the United States.

The goal was to establish enough domestic capacity to supply vaccine within six months of the start of a pandemic to the entire U.S. population of about 300 million.

Building up U.S. production is still ongoing.

Sanofi-Aventis SA is the major supplier for the U.S. market, making about 50 million doses annually at a plant in Swiftwater, Pennsylvania.

A second Swiftwater plant could produce another 50 million doses of seasonal vaccine this year if cleared by U.S. regulators, Sanofi spokeswoman Donna Cary said.

When fully operational, that plant could churn out 100 million doses of the three-strain seasonal vaccine, said Cary, but she declined to say when that would be.

Other companies including GlaxoSmithKline and Novartis make at least part of the vaccine outside the U.S.

Phenomenal Expansion

The funding for vaccine manufacturing has produced "phenomenal expansion in manufacturing capacity," Dr.

Anne Schuchat, an interim deputy director at the Centers for Disease Control and Prevention, told a Senate hearing.

Asked if the United States could produce 300 million doses domestically now, Schuchat said officials were "very optimistic," but added: "This virus can surprise us, and even with all those investments it may just technically be difficult." Other experts agreed preparedness efforts had helped, particularly with Sanofi boosting its U.S.-based production.

"We are in a good position right now in the United States," said Dr.

Kathleen Neuzil, who serves on the pandemic flu task force of the Infectious Diseases Society of America as well as a U.S. government advisory committee on vaccines.

Companies limit production each year based on how much officials think they can sell, and they could make more, she added.

Also, the seasonal vaccine contains three flu strains, but a pandemic vaccine might need only one. "You can make three times as much if only one strain is in the vaccine," Neuzil said.

Osterholm said it was too soon to predict the U.S. capacity, as it would depend in part on what dose would be needed and whether it could be stretched with an ingredient known as an adjuvant.

"There clearly has been some increase (in capacity), but it's not clear what the increase is," he said.

Neuzil said antiviral drugs could help address any shortfall by treating or preventing the flu, although the medicines do not offer long-term protection. She said she worried more about vaccine availability for poor countries than for the United States.

"Ninety-five percent of influenza vaccine is made in the U.S. and Europe. As a global community, we also need to consider supply for the low-resource countries," she said.

Copyright 2009 Reuters. Click for restrictions.