A growing number of flu shot clinics across the Washington region are being delayed, if not outright terminated, because of lagging vaccine deliveries to doctors, hospitals and corporate providers.

Despite continuing assurances from federal officials that enough doses will be available before the annual flu season hits in force, the sudden turnaround here and in other states is a vexing deja vu for many people. They say it is far too reminiscent of the shortages and confusion that caused such fears last winter.

"I'm so frustrated. I have people coming in saying they can't get a shot at their regular doctor, their oncologist," said Betty Timer, director of the Margaret Schweinhaut Senior Center in Silver Spring, who faced 200 "very angry" patrons last month when she had to post a "flu shots postponed" sign at the last minute.

"Our government told us we would have no problem this year," Timer complained yesterday. "We're not being told the truth. There's a problem."

Just this week Inova Health System, worried that it probably will be 25,000 vaccine doses short of its target for the season, again restricted its hospital-based program to high-risk groups and canceled its remaining clinics at libraries, churches and workplaces.

"We are very disappointed that this situation has occurred once again this year," said Beth Visioli, a spokeswoman for the Northern Virginia not-for-profit medical organization. "We are attempting to secure other vaccine supplies, but as other providers across the nation face a similar situation, we are not finding many available additional supplies."

By this weekend, the company that probably gives more flu shots in the Washington region than any other public or private entity could make a similar decision for its schedule. Maxim Health Systems, the force behind the vaccination clinics in many supermarkets and drugstores, is still awaiting nearly a third of its 2.2 million-plus order and will say only that it is assessing things "day to day." But few clinics are advertised after Saturday on its Web site, www.findaflushot.com.

"It seems like a large number of providers can't find vaccine," Maxim official Steve Wright acknowledged yesterday.

The federal Centers for Disease Control and Prevention says that nearly 90 million doses are still anticipated from four companies, up from about 61 million and two companies in 2004, and that more than half of that is in the pipeline. "We're expecting enough, based on the information we've received from the manufacturers," CDC spokeswoman Lola Russell said.

The problems, whether temporary shortages or something more extended, apparently stem from the scaled-back distribution from Chiron Corp., which had its entire production barred last year because of contamination concerns. Chiron initially said it would have 18 million to 26 million doses available. Its prediction now is no more than 18 million, only a fraction of which have been approved by regulators for release.

Russell stressed that vaccinations well into December "are not too late" to protect against the flu bug -- the virus that comes around annually, not the avian flu strain that is now commanding worldwide attention because of concerns it could mutate and cause a devastating pandemic.

And she noted that a vexing situation is not the same as a dire situation. Numerous city or county health departments locally report being in good shape: "It's not like there are no shots in the D.C. area at all."

Yet none was available as promised at 2 p.m. yesterday at the Fairfax City Regional Library. Dozens of people stopped short, in frustration and irritation, when they walked to the front door and saw a sign taped to the glass: "The flu shot clinic scheduled for today has been canceled by Inova."

"This is bad, very bad," said Ernest Klimonda, 79, of Fairfax, who last winter searched until January for a shot. "You've got to run from one supermarket to another, and they're all canceled. They tell you to come at 8 when it opens at 9, and by 8 the line is already closed. A country like the United States should really do better."

Ed Seydel of Oakton was more sanguine, despite coming up short twice in one day. Hours earlier he had gone to a Giant supermarket clinic, but its stock was exhausted.

Rene Arias and his wife, Lupe, said they felt they had squandered most of the afternoon on their futile excursion. The Annandale couple, proprietors of a household cleaning business, drove 45 minutes to get to the library. The day before, they had gone to a Kmart offering flu shots.

That clinic had been canceled, too.

Betty Powell stops at the door of the Fairfax City library branch, where a sign said, "The flu shot clinic scheduled for today has been canceled by Inova."