FRIDAY, Oct. 23 (HealthDay News) -- Production delays continue to hamper distribution of the H1N1 swine flu vaccine, a leading U.S. health official said Friday.

The vaccine is growing more slowly in egg-based cultures than manufacturers had anticipated, resulting in fewer available doses at this time, Dr. Thomas R. Frieden, director of the U.S. Centers for Disease Control and Prevention, said during a news conference.

As of Friday, there were 16.1 million doses on hand nationwide, up from 14.1 on Wednesday, Frieden said. And there will be far fewer than the 40 million doses originally planned for the end of October, he added.

"Vaccine availability is increasing steadily, but far too slowly," Frieden said. "It's frustrating to all of us. We are nowhere near where we thought we would be by now. We are not near where the vaccine manufacturers predicted we would be."

The vaccine that is available comes in both nasal mist and injectable forms. The first doses were only the nasal spray, called FluMist, designed for healthy people 2 to 49 years of age. But now, more than half the doses are injectable, he said.

The H1N1 swine flu continues to produce mild-to-moderate disease in most people, Freiden said. The flu is now widespread in 46 states, he said, adding, "We have already had millions of cases of pandemic influenza in the United States and the numbers continue to increase."

There have been 1,000 laboratory-confirmed deaths due to swine flu since April, according to the CDC.

While children continue to be particularly vulnerable to the disease, Freiden said, "we are seeing it increasingly affect young adults as well as children. We are still not seeing significant numbers of cases among the elderly and that's characteristic of this virus."

That's also a marked difference from run-of-the-mill seasonal flu, which typically poses a much bigger threat to the elderly.

There is encouraging news, Frieden said. The genetic makeup of the H1N1 virus hasn't changed, meaning the swine flu vaccine and the antiviral drug Tamiflu are a good match.

Frieden said the H1N1 flu would probably occur in waves, but "we can't predict how high, how far or long the wave will go, or when the next will come."

"We are now in the second wave of pandemic influenza and whether this will continue through the fall into the winter, whether it will go away and come back in traditional flu season, only time will tell," he said.

Although seasonal flu outbreaks can occur as early as October, most of the time seasonal flu activity peaks in January or later, according to the CDC.

Frieden said that, unlike the H1N1 vaccine, seasonal flu vaccine is plentiful with about 85 million doses distributed so far; more than 60 million people have been vaccinated. "That is way more way sooner than in any prior year," he said.

Until the swine flu vaccine is widely available, experts are urging people to follow oft-stated guidelines, namely avoid crowds, use good respiratory etiquette (i.e. sneeze into your sleeve) and wash your hands frequently.

"Although vaccines are probably the best option, they're not the only option," said Dr. John Treanor, chief of the infectious diseases division at the University of Rochester Medical Center in New York. "We'd love to have the vaccine available now, but for the time being, it looks like we'll have to rely on those non-vaccine interventions."

In other swine flu developments:

• The World Health Organization reported Friday that nearly 5,000 people are thought to have died from the H1N1 flu since it first emerged last spring in Mexico and the United States before sweeping around the globe.
• A CDC survey released Thursday found that one in five U.S. children had a flu-like illness earlier this month, and most of the cases were probably swine flu. About 7 percent of adults said they'd had a flu-like illness, the survey found, the Associated Press reported. The results buttress health experts' belief that children and young adults are more susceptible to the swine flu than older adults, who are thought to have some immunity to the disease.
• U.S. health officials are once again warning consumers about products that are popping up on the Internet that make unsubstantiated claims about preventing or treating the swine flu. These product include: a shampoo said to protect against the H1N1 flu virus, a dietary supplement said to protect infants and young children from contracting the virus, a "new" supplement said to cure H1N1 flu infection within four to eight hours, and several diagnostic tests that have not been approved to detect the H1N1 virus, according to the U.S. Food and Drug Administration.
• New York state health officials have decided not to require health-care workers across the state to get the swine flu vaccination or risk losing their jobs, since the vaccine is in short supply. Health-care workers had sued the state over the directive, saying it was a violation of their civil rights, according to published reports.

More information

To learn more about the H1N1 swine flu, visit the U.S. Department of Health and Human Services.

SOURCES: John Treanor, M.D., professor, medicine, and chief, infectious diseases division, University of Rochester Medical Center, Rochester, N.Y.; Oct. 23, 2009, news release, U.S. Food and Drug Administration; Oct. 23, 2009, teleconference with Thomas R. Frieden, M.D., M.P.H., director, U.S. Centers for Disease Control and Prevention

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