In recent years, finding a flu vaccine may have felt like running an obstacle course or maybe just not worth the trouble. But those who were too discouraged or too blasé need to get on the stick this year, national and local health officials said Wednesday.

The official start of influenza season is Oct. 1. At a news conference Wednesday in Washington, officials bemoaned the 2005-06 season's relatively low rates of immunization, particularly among those most at risk of dying from the flu.

Closer to home, the Dallas County health department is figuring out how to distribute the 2,200 doses of vaccine it already has – they will be available beginning Oct. 1 – and the 8,000 or so more on order.

Their consistent message: After three years of sometimes-unreliable vaccine supply, this year's shipments look to be fine. So everyone older than 50, every adult with any other risky medical condition, and every parent of a child younger than 5 should be making plans to get vaccinations. As should anybody else who wants to miss out on the ravages of the disease and whose doctors say they can handle the vaccine.

"The real dilemma is making sure that we have a seamless distribution," said Zachary Thompson, director of the Dallas County Department of Health and Human Services. "There should not be an interruption. The 2004 fiasco confused everybody."

In 2004, one of the multinational pharmaceutical companies making the vaccine had to shut down, creating a real shortage. For the past two years, plenty of doses were prepared, but distribution hiccups created a shortage right when the health care publicity machine was cranking up, urging people to get vaccinated.

The combination has not been good news for an ongoing national campaign to get more high-risk people vaccinated. The figures released in Washington by the Centers for Disease Control and Prevention covered the 2005-06 immunization season: Only 20 percent of children ages 6 months to 23 months, 30 percent of at-risk adults ages 18 to 49 and 69 percent of people 65 and older got vaccinated.

The adult immunization numbers were worse than two years earlier, down 5 percentage points for the at-risk adult group and down more than 5 percentage points for the 65-and-older group.

From a longer perspective, the rates may not have been so bad. In 1998, about 64 percent of Americans older than 65 got the shot. In 2005-06, the figure was more than 5 percentage points higher. On the other hand, the government's official target for this population is 90 percent immunized by 2010.

"If we have the vaccine on Day One, and we have a steady supply and it is consistent year after year, you will see those numbers increase," Mr. Thompson said.

The other statistics issued Wednesday by the CDC and the National Foundation for Infectious Diseases were plenty scary. Influenza kills about 36,000 people a year in the U.S. and may trigger an additional 92,000 fatal heart attacks. It hospitalizes 200,000 more. The financial cost to the country is more than $87 billion in health care and lost productivity.

Hidden behind the numbers is the awful way the flu makes people feel. The vast majority of people who get it don't die – but many might not think that's a bad idea while in the throes of the fever, chills and body-wracking aches of a serious case.

If you don't feel that terrible, you probably have not really had the flu.

"The lay use of the term the flu encompasses every winter cold," said Dr. Bill Schaffner, an infectious-disease specialist at Vanderbilt University medical school and vice president of the national foundation. "I remind them colds don't put people into the hospital and kill them."

The flu edges into the U.S. as early as October and can linger into May. A vaccination takes a week or two to confer its maximum benefit, so there's an advantage to getting it early. But each year's batch has to be created from scratch – the viruses change a bit every year – so the manufacturers can't have a full supply for the start of the season, Dr. Schaffner said.

About 20 million doses – of the expected 130 million that will be available in the U.S. – have been distributed so far.

Distribution bobbles aside, it's generally easy to get immunized.

Just about every doctor's office or clinic stocks the vaccine. Most insurance covers all or part of the cost, and Medicare pays for it all. Public health facilities such as the Dallas County health department offer low-cost immunizations. And for the past two years, many people even had the option of passing up the needle for an inhaler-delivered vaccine.

Why don't more people get it?

In recent years, some people decided to step aside for others they figured needed it more, said Curtis Allen, a spokesman for the CDC. Others may have forgotten how bad the flu can get.

The uncertain supply affected older people and toddlers particularly, said Mr. Thompson of the Dallas County health department. Many of his older clients come for their vaccinations in early October like clockwork. When the supply failed in recent years, some people were shut out and never came back. And the pediatric vaccine didn't show up until several weeks after the adult supply, so a family who came for adult vaccinations was unable to get the children vaccinated at the same time.

Representatives of the national organizations said Wednesday that people should not all crowd up the first week and then give up if they are shut out. Flu season lasts for months, well past mid-November when demand for the vaccine usually drops off. Last year, vaccine companies had to throw away 20 million doses of unused vaccine.

This year, health officials say, about 218 million people at particular risk should seriously consider getting the vaccine. But enough people won't that they expect the supply of 130 million doses will be plenty.

"If we don't use it, we lose it," Dr. Schaffner said. "Next year, the manufacturers may not make as much if we don't use up the supply this year."

States with the highest estimated rates of influenza vaccination during the 2005-06 flu season:

Ages 18-49

2. Louisiana: 41.9%

3. Nebraska: 40.5%

4. S. Dakota: 40.3%

5. Hawaii: 39.5%

Texas: 38.8% (6th)

Nation: 30.5%

Ages 50-64

2. Rhode Island: 47%

3. Colorado: 46.9%

4. Oklahoma: 45.4%

5. Utah: 45.3%

Texas: 35.5% (43rd)

Nation: 36.6%

Ages 65 and older

2. Colorado: 77.3%

3. Hawaii: 77.1%

4. Minnesota: 76.9%

5. Iowa: 76.5%

Texas: 67.3% (40th)

Nation: 69.3%

SOURCE: Centers for Disease Control and Prevention