FRIDAY, Nov. 6 (HealthDay News) -- Although the total doses of H1N1 swine flu vaccine available in the United States now tops 38 million -- 11 million more than a week ago -- most Americans who want a shot still haven't been able to get one, U.S. health officials acknowledged Friday.

In fact, 70 percent of adults and 66 percent of children who tried to get vaccinated couldn't, according to a poll conducted last weekend by researchers at Harvard University School of Public Health.

"I think it was understandable that people were finding it difficult for people to find vaccine at the time of the poll, because we were and still are at a point where the supply is relatively limited, compared with the demand," Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases at the U.S. Centers for Disease Control and Prevention said during a news conference Friday.

One positive finding of the Harvard poll was that nine out of 10 people said they would try again to get vaccinated, she noted. "They weren't giving up. They weren't so frustrated that they had had it. They recognized the value of protecting themselves with vaccine, and sticking with it through the next several weeks."

Schuchat noted the vaccine supply would continue to increase and next week an additional 8 million doses are expected. However, she was cautious in making any predictions about vaccine supply beyond next week.

"I am expecting in the next several weeks things will get better and better," she said. "But, we have all been burned on predictions, so I am not going to get more specific than that."

As demand for both H1N1 swine flu vaccine and the seasonal flu vaccine has reached unprecedented levels, the H1N1 strain continues to circulate and is widespread in 48 states.

More people are being hospitalized and confirmed deaths from swine flu among children have reached 129, according to the CDC. Of these children, two-thirds had underlying medical conditions such as cerebral palsy, muscular dystrophy and asthma, Schuchat said.

Among deaths from H1N1 flu, 90 percent are among people under the age of 65, and over 50 percent of those hospitalized are under 25, she said. That's, "a flip-flop with what we see with seasonal flu," where many fatalities occur in the elderly, Schuchat said.

Last week, a CDC report estimated that for every confirmed case of swine flu there were 79 unreported cases. In all, the agency estimated that there have been between 1.8 million and 5.7 million U.S. cases of flu, as well as 9,000 to 21,000 hospitalizations and about 800 related deaths.

Those who should be near the front of the line for a swine flu shot include pregnant women, children, people who care for infants, health-care workers, and people with chronic medical conditions such as asthma, diabetes and heart disease.

In addition, adding to the H1N1 vaccine shortage is a shortfall in available seasonal flu vaccine. So far, 91 million doses of seasonal flu vaccine have been distributed out of a total of 114 million doses expected to be available. When the remaining doses would be available, Schuchat could not say.

On Thursday, CDC Director Dr. Thomas Frieden sent a letter to state and local health officials urging them not to forget the goal of the H1N1 vaccination program, especially as shortages continue.

"The goal of the H1N1 vaccination program is to protect our population -- focusing first on these high-risk groups and ensuring equitable access to the vaccine," Frieden wrote. "While vaccine supplies are still limited, any vaccine distribution decisions that appear to direct vaccine to people outside the identified priority groups have the potential to undermine the credibility of the program...I ask each of you to review your plans immediately and work to ensure that the maximum number of doses is delivered to those at greatest risk as rapidly as possible."

In part, the letter was sent due to media reports that Wall Street firms corporations such as Goldman Sachs and Citigroup were getting swine flu vaccine ahead of hospitals and clinics. The story was originally reported on Nov. 2 by Business Week.

More information

For more information on H1N1 swine flu, visit the U.S. Centers for Disease Control and Prevention.

SOURCES: Nov. 7, 2009, teleconference with: Anne Schuchat, M.D., director, National Center for Immunization and Respiratory Diseases, U.S. Centers for Disease control and Prevention; Nov. 2, 2009, Business Week

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