All states have ordered H1N1 influenza vaccines, a top federal health official said Tuesday.

The U.S. has purchased 95 million H1N1 vaccines and enough bulk ingredients from five companies to make up to a total of 251 million vaccine-doses if needed. The vaccines will be distributed to states and some large cities, which in turn will distribute the vaccines to about 90,000 health-care providers, retailers and local health departments over a period of several weeks.

Thomas Frieden, the director of the Centers for Disease Control and Prevention, said Tuesday that "tens of millions" of vaccines will be made available in the next few weeks. This week, the first doses of MedImmune's H1N1 flu-mist vaccine are being administered. The first flu shots will be given starting next week.

MedImmune, which is a unit of AstraZeneca PLC (AZN), makes a mist that's delivered through the nose and is approved for "healthy" people ages 2 to 49. It's not approved for use in pregnant women, who've been hit hard by the H1N1 flu. Pregnant women are being urged to get an H1N1 shot when they become available.

Other companies including a unit of Sanofi Aventis (SNY), Novartis AG (NVS), CSL Ltd. (CSL.AU) and GlaxoSmithKline PLC (GSK) are making H1N1 flu shots for the U.S. market. Last week, Sanofi said it started shipping vaccine to the U.S. government.

Frieden said that as of Monday about 2.4 million vaccine doses were available for order and that about 2.2 million have been "drawn down or ordered."

While demand from states for the H1N1 vaccine appears to be strong, it's not clear how strong demand will be from the American public. In a typical year about 100 million Americans opt for a seasonal flu shot.

A poll released last week by Consumer Reports found that 34% of people surveyed said they'd get an H1N1 vaccine when it became available. The poll also found that 50% of parents where holding off on making a decision about whether to have their children vaccinated with some citing concerns about vaccine safety.

Frieden acknowledged that many people are worried about the new vaccine. He stressed that the H1N1 vaccine is being made in exactly the same way by the same companies that make seasonal vaccines. Seasonal vaccines typically change each year. It was too late to incorporate the H1N1 virus into the seasonal vaccine because production was underway when the virus was first detected last April. If the H1N1 virus sticks around, it will likely be incorporated into next year's seasonal flu vaccines.

-By Jennifer Corbett Dooren, Dow Jones Newswires; 202-862-9294; jennifer.corbett@dowjones.com