By Amanda Gardner
THURSDAY, Oct. 22 (HealthDay News) -- As reports of swine flu infections continue to pour in from across the United States, health experts labored Thursday to explain why delivery of stocks of the long-awaited H1N1 vaccine are falling behind schedule.
Federal officials had projected that 40 million doses would be on hand by Oct. 15, but not even 13 million doses had arrived by Tuesday.
"They [federal health officials] made some earlier projections, but it looks like a number of those projections have been overly optimistic," said Dr. Ciro Sumaya, a professor at the Texas A&M Health Science Center School of Rural Public Health, and a member of the U.S. Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices.
On Tuesday, a top CDC official acknowledged that production of the vaccine was lagging, with a revised goal now of 50 million doses by mid-November and 150 million by year's end.
"I understand and share everyone's desire to have more vaccine. I wish that we had more than we have right now, but we do have more coming out every day," Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases, said during a press conference.
The resulting shortage has forced the delay of many mass vaccinations, and harried doctors are dealing with worried parents anxious to get their children inoculated. While the swine flu continues to produce mild-to-moderate disease in most people, children and young adults seem most vulnerable to the virus. During the six-week period ending Oct. 10, 27 states had reported 4,958 people hospitalized with H1N1 swine flu, and more than half -- 53 percent -- of those people were under the age of 25.
Experts such as Sumaya explained that glitches can -- and apparently did -- occur at several points in the complex process of developing a vaccine, especially for a virus that was first identified in April.
"It shows how there are many steps before you get a vaccine that's available -- the production, the testing, the packaging, the allocation and distribution. And there may be problems at every step, so as you go from one to the other to the other that slows things down," he said Thursday.
Sumaya was attending a meeting of the CDC advisory committee in Atlanta, where the experts were collecting information on vaccine supply and demand, as well as getting up to speed on the latest H1N1 developments, how the virus is spreading across the country, how many people have been hospitalized and how many have died.
In explaining the vaccine delay, Sumaya said that, first, the H1N1 virus did not grow as quickly as expected during a half-century old -- and often-criticized -- egg-based production technique.
Second, he said, "because there was kind of a rush to get things done, there were some packaging areas that they [federal officials] had thought wouldn't take long, yet they did."
"Even in the distribution, to find certain target groups so it reaches them first, we have to have a sense of what is going on across the country, which is a dynamic situation," he added.
Then there are the twin demands facing vaccine manufacturers to produce two different vaccines at the same time -- one for swine flu and one for seasonal flu.
"We're trying to provide recommendations on how they can improve the situation," Sumaya said.
In explaining the vaccine delay, Dr. Nicole Lurie, assistant secretary for preparedness and response with the federal government's Biomedical Advanced Research and Development Authority, said in a statement: "We have said from the start that flu is unpredictable, and so is the production of flu vaccine. Production of the vaccine is taking longer than manufacturers expected because of the time it takes to grow theantigen for the vaccine. There is nothing that can be done to speed thatprocess, because it's important for the vaccine to be as effective aspossible and follow all the safety protocols."
"We think we made very good progress in the six months from May to today, when millions of doses of safe H1N1 vaccine have been ordered by the states," she added. "While this may feel like a slow start, it's actually a significant achievement to have what we believe is a safe and very effective vaccine to fight a pandemic flu this quickly. Every American who wants and needs to get an H1N1 vaccine will be able to get one."