The supply of vaccine for the coming winter's flu season may be the biggest in the country's history, but with vaccination clinics barely underway, it is too early to know if it will be enough to meet the demand.

Total supply could be as high as 97 million doses, about a third more than was available last year when the sudden loss of one company's total production created a frantic search for flu shots nationwide.

Partly in response to that shortage, the government and the biggest manufacturer have taken steps to assure that vaccine goes first this year to those who need it most. Ironically, that strategy may be the reason some clinics are reporting "spot shortages" because they have not yet received their full orders.

"Right now it looks like demand is going to be good. It also looks like supply is going to be good," said Donald E. Williamson, the state health officer of Alabama and spokesman for the Association of State and Territorial Health Officials. But, he said, health care providers will not know the true demand for flu shots until they start vaccinating low-risk people -- a process that under federal guidelines is not supposed to happen until Oct. 24, and will not begin in earnest until well into November.

In the Washington region, many public health agencies and hospitals ordered more doses than in a typical year -- anticipating higher demand because of last winter's problems -- and officials are confident they will receive those supplies in full. Clinics began in early October, with few problems or shortages reported.

"Everything seems to be going according to schedule," said Danna Kauffman of Mid-Atlantic LifeSpan, which represents more than 300 senior-care organizations in Maryland and the District.

Adding to the uncertainty is publicity about the spread of H5N1 avian influenza from Asia into Europe. (Its presence in birds in Romania was confirmed yesterday.) Although the seasonal flu vaccine does not protect against bird flu, fears of a possible pandemic of the latter may have raised public consciousness about influenza in general.

In all, four companies produced vaccine for the U.S. market this year. Three made injectable vaccine, and one -- MedImmune, which has its headquarters in Gaithersburg -- made a nasal-spray containing live but weakened flu virus. It can be given only to people ages 5 to 49 who are not pregnant.

Chiron Corp., the California biotech company whose production of 48 million doses was judged unacceptable for use last fall by the Food and Drug Administration, made between 18 million and 26 million doses. Last week, the FDA tested and approved the first three lots of about 500,000 shots each.

Sanofi Pasteur, a division of a French pharmaceutical giant, made 60 million doses, the most of any company supplying the U.S. market. It shipped 33 million doses by the first week in October. With the approval of the U.S. Centers for Disease Control and Prevention, it sent nearly all its customers a part of their orders so they could start vaccinating high-risk groups. The balance will be shipped by mid-November, said Len Lavenda, a Sanofi spokesman. A new producer this year is GlaxoSmithKline, which made 8 million doses.

If Chiron meets its upper-end production estimate -- it will not announce its production totals until later this month -- the nation will have a total of 97 million doses. That is 2 million more than the 2002 record of 95 million, a year in which 12 million doses went unused.

Under federal guidelines, the people who should get shots first include nursing home residents, those older than 65, younger people with chronic illnesses such as diabetes and asthma, children between 6 months and 2 years, pregnant women and health workers.

None of these groups ever gets fully immunized, however. Two years ago, 66 percent of those older than 65 got flu shots. With last year's shortage, the figure was 63 percent. Health care workers are a priority group because they can spread flu to their patients, but their vaccination rate is even lower. In 2003, 40 percent were vaccinated; last season, it was 36 percent.

After more than 130 U.S. children died from influenza or its complications in the 2003-04 season, the government began advising that all healthy toddlers get flu shots. The fact that 48 percent did the next year "suggests how quickly physicians and parents can adopt a new disease-prevention guideline," a CDC official wrote in a report this year.

This season, many health care providers, especially those caught short last year by ordering through only one source, hedged their bets.

The Anne Arundel County health department placed orders with all four companies "as a measure of covering all our bases and getting an adequate amount of vaccine," spokesperson Elin Jones said. Its clinics for county residents will begin next week, and about a third of 30,000 doses are in stock.

The county's flu information line is fielding inquiries, but "there is not that urgency or concern" that ratcheted to near-panic last October with news of the shortage. People "feel they will be able to get vaccine," she said.

The District health department raised its goal by more than 2,000 doses, hoping to administer more than 21,100 shots this season. It expects to have all in hand by mid-November.

Virginia's local health departments are waiting for more than half of their 230,000 doses -- up 27 percent from 2004. Jim Farrell, director of the state division of immunization, said he is not worried about shortages but acknowledged that nearly every aspect of flu season is unpredictable.

This early, there's nothing but anecdotal evidence on how the public is responding. Calls to the Inova Health System's "Fight the Flu" hotline have climbed dramatically in the past two weeks, as have inquiries from groups hoping to schedule vaccination clinics.

"The early returns would suggest that the volume of calls . . . is ahead of what we normally see," said Inova epidemiologist Allan Morrison. Inova has 45,000 doses in stock, with 35,000 more expected soon.

But late Thursday afternoon, there were three chairs, two nurses, plenty of shots and no line at the Giant grocery on Eighth Street NW.

Four hours of work yielded 75 vaccinated shoppers, many in their late sixties and early seventies, or with health problems such as diabetes and hypertension. Nevertheless, that was far below the usual 300 during the heart of a flu season.

"We have spurts, then it slows down," said nurse Meredith Higgins, with Maxim Health Systems.

Harriett Harper happened by and was surprised by the lack of a crowd. The retired federal economist had meant to call her doctor, but she said she did not want to pass up this opportunity. She got a flu shot and, for the first time, a second vaccine that protects against pneumococcal pneumonia.

"One in the left arm, one in the right," she said, and then kept on shopping.

Meredith Higgins of Maxim Healthcare Systems gives a flu shot to Margareth Jones at a Giant on Eighth Street NW.