The federal government will supervise the distribution of flu vaccine stocks that have not yet been shipped, health officials said yesterday, adding that they have already diverted about 4 million doses to areas with the greatest need.

The announcement came a week after officials said they learned that half the nation's expected vaccine supply for the coming winter would not be available because British regulators had found manufacturing problems at the Liverpool plant of one of the two U.S. suppliers, Chiron Corp. The only other manufacturer, Aventis Pasteur, has produced 55.4 million doses, but nearly two-thirds of that supply has already been distributed, company officials said yesterday.

The Centers for Disease Control and Prevention urged last week that only individuals in designated high-risk groups, totaling nearly 100 million people, seek the vaccine, but the sudden shortage has left some health facilities with no vaccine at all. Around the Washington area, sites that had the vaccine reported long lines, sore feelings and frustrated customers yesterday.

Police were called out to calm flu-shot hunters and direct traffic at the gridlocked parking lots of Giant supermarkets that had advertised flu-shot clinics.

"We're mobbed. Every store has lines," said Barry Scher, a spokesman for Giant. The chain plans to continue handing out numbers to those who show up -- as long as they are in one of the high-risk groups -- but will do so only 30 minutes before a clinic's scheduled start.

"We're urging people to please be patient," Scher said. "We're doing the best we can with limited vaccine."

At a Giant supermarket in Ellicott City, nurse Margaret Christian was exasperated with the clamor as more than 400 people crowded in for shots.

"We tell people we're out of vaccine, and they stand there and tell us they want a shot anyway," she said. "It's an incredible situation."

In Silver Spring, the Giant pharmacy near Leisure World had given out all its 400 tickets for flu shots by noon, said Jeanette Lewin, who got there too late. Lewin, who noted that she is older than 65, said a man in line told her that he had been there since 6 a.m. The line wrapped around two or three aisles, and some people sat on beach chairs, Lewin said.

"It was appalling," she said. "There were all these people in wheelchairs, with canes, with strollers, waiting there patiently. It was like a scene you'd see at Lourdes."

Lewin said she will try again on Thursday. "I might have to wake up at 3 a.m. to get there in time, which is crazy," she added.

Officials said large numbers of high-risk people will be left without vaccine -- the exact number depends on how many seek the shots, the success of the redistribution effort, and the willingness of doctors and the public to honor requests to save the vaccine for those at high risk.

"We're sorry for the people who need flu vaccine and may not be able to get it this year," said Julie L. Gerberding, director of the CDC. She predicted that the government's choices "probably will not make everybody happy."

Officials expect only 42 million to 50 million of those at high risk to seek vaccination, based on trends of previous years.

Gerberding called healthy adults who are willing to forgo vaccination "health heroes." She acknowledged that the vaccine crunch comes at precisely the time when officials had hoped to increase the number of Americans who get flu shots.

The volume of Aventis Pasteur stocks that has been administered is not known. Officials hope to redirect the remainder of the supply so that all states would receive at least half the amount they need for high-risk individuals, which include all adults 65 and older, children 6 months to 23 months in age and anyone with a chronic medical condition.

High priority is being given to Veterans Administration facilities, the Defense Department and people in long-term-care facilities.

Gerberding said public health officials will keep tabs on which states and counties have received little or no vaccine, track where the flu hits hardest and evaluate where people are filling flu-related prescriptions to help agencies decide where to send the remaining supply of about 8 million doses.

Gerberding warned distributors against price gouging. The Associated Press reported that charges were filed yesterday against a Kansas distributor who tried to sell vaccine to a pharmacy with a 1,000 percent markup.

Damian Braga, U.S. president for French-based Aventis Pasteur, said there is no way the 33 million doses his company has already shipped could be rerouted. Of the remainder, Braga and Gerberding said, about 11 million doses are headed to high-risk populations. About 4 million doses that had been purchased for non-high-risk groups are being redirected.

Braga could not say which areas will get the 4 million doses, or from where they are being diverted.

About 36,000 Americans die of the flu each year. Last year, Gerberding said, about 83 million doses of the vaccine were used out of a stockpile of 87 million doses. Under normal conditions, as many as 180 million Americans could benefit from a flu shot, she said.

The CDC plans to increase stockpiles of FluMist, a live-virus vaccine given as a nasal mist, and prescription flu medication that can be targeted at high-risk areas or regions with flu outbreaks. Officials said they are willing to explore alternate vaccine sources in Britain and Canada if there are data showing that the products are safe and effective.

While some research has shown that giving the flu vaccine in half doses can result in effective protection, Bruce Gellin, director of the national vaccine program office at the Department of Health and Human Services, said studies have not been done on whether that would work with this year's vaccine. Gellin predicted that strategy will not be used this season.

Gerberding urged that high-risk people go to their usual sources of flu shots and contact physicians if the vaccine is not available.

"We say, be patient, but also be persistent," she said.

The acute shortfall was triggered after concerns were raised in Britain that vaccine made at the Chiron plant in Liverpool had been contaminated by bacteria. No shipment from Chiron has been administered to U.S. patients, Gellin said.

Chiron disclosed in a regulatory filing yesterday that a New York federal grand jury has asked for documents related to the vaccine plant shutdown.

A spokesman for the U.S. attorney in Manhattan, who is overseeing the probe, declined to comment, but sources familiar with the investigation said prosecutors are looking both at Chiron's interaction with health authorities and its disclosures to investors. Chiron's shares have fallen about 25 percent since regulators shut down the plant. A spokesman for the company declined to comment.

Staff writers Susan Levine, Katherine Shaver, Brooke A. Masters and Susan DeFord contributed to this report.

Nurse Anna Ruby, right, tells about 400 people at a Giant supermarket in Ellicott City that only 300 doses of flu vaccine are available. More people than available doses of flu shots show up in Ellicott City. Around the Washington area, sites that had the vaccine reported long lines and sore feelings.