Sanofi Pasteur, the vaccine unit of Sanofi-Aventis, said it would have 50 million doses this year. Novartis AG said it would have 40 million doses, GlaxoSmithKline Plc said it would have 30 million to 35 million doses and MedImmune said it would provide 7 million doses.

And an Australian vaccine maker, CSL Ltd., said it could provide 7 million additional doses, if it got approval from the U.S. Food and Drug Administration. That would bring the supply to more than 130 million doses for the 2006-2007 flu season.

"CSL want to commercialize vaccines in the U.S. market. Our plan is to have vaccine available in 2007-2008 depending on FDA approval," Paul Perreault, executive vice president for worldwide operations at the company, told a meeting organized by the CDC.

The CDC and other health officials, eager to increase the share of Americans who get flu vaccines, are trying to encourage companies to boost their capacity to make influenza vaccines for the U.S. market.

Seasonal influenza kills about 36,000 people in an average flu season, and puts 200,000 into the hospital in the United States.

But making flu vaccines uses old and risky technology involving chicken eggs and months of incubation, and few companies want to make them. Batches must be mixed up fresh every year to match the various flu viruses that are circulating because they mutate every year.

The supply can also be wiped out easily -- as in 2004, when the United States lost half its flu vaccine supply when a British based maker suffered contamination and was shut down for a year.

But usually, hundreds of thousands of doses of vaccine go unused every year and are thrown away. The system for distributing vaccines -- based mostly on private distributors -- is unpredictable and delivers vaccines at various times throughout the season.

The result is that people often cannot get vaccines when they want them. CDC says it is working on this problem, although the government agency has little authority over the private distributors.

Last year the U.S. flu market had about 100 million doses. The CDC says that most Americans should be vaccinated against the flu every year, but fewer than half of those who should get the immunization actually do.

Experts want to get people in the habit of annual vaccines to create a market for them, because they say a flu pandemic is inevitable.

Because there is such a limited market for the vaccines, companies do not make them in large numbers. The total global supply is estimated at about 400 million doses a year, far short of what would be needed in a pandemic.

The H5N1 avian influenza virus circulating among birds in Asia, Europe, the Middle East and Africa is considered the No. 1 andidate for causing a pandemic. It does not easily infect people now but has killed 172 people out of 291 known to have been infected worldwide.