The federal government will announce a plan this week to purchase additional flu shots (search) to help relieve the nation's shortage, the director of the Centers for Disease Control and Prevention said Monday.

Dr. Julie Gerberding told delegates at the American Medical Association's annual winter meeting that outgoing federal Health and Human Services Secretary Tommy Thompson is expected to make the announcement.

"We do have optimism additional doses can be purchased. We hope for an announcement later in the week from Secretary Thompson," Gerberding said.

Thompson said last month that the Food and Drug Administration has completed its inspection of the vaccine from foreign manufacturers that would be available on an investigational basis. The vaccine is considered an investigational new drug because it wasn't developed under the supervision of the FDA.

Gerberding cautioned that the nation's health care officials should not relax due to the flu season's slow start, with no widespread outbreak reported.

"A slow start doesn't necessarily reflect a slow season," she said. "The most common month of peak activity is February."

Health officials had planned on having more than 100 million doses of the vaccine this season, the biggest supply ever. But flu shot maker Chiron Corp. announced on Oct. 5 that it could not ship its 48 million doses after British health officials suspended the maker's license because of contamination at a Liverpool plant.

The resulting shortage has been a major concern expressed by AMA delegates, who have proposed resolutions to have the vaccine reach high-risk patients as a top priority, instead of on a first-come basis. The resolutions were expected to come to a vote by the meeting's conclusion Tuesday.

Gerberding, however, said "the volunteerism works" as most Americans followed CDC guidelines for reserving the vaccine for high-risk patients.

"The people who should step aside stepped aside," she said, adding that she does not endorse trying to penalize healthy patients who are taking the vaccine.

About 61 million doses have been available this season, including a nasal vaccine only for healthy people. The CDC has said 98 million people, including 9 million children, need the vaccine.

Each year, the flu hospitalizes about 200,000 people and kills about 36,000 people in the United States.