Swine Flu Vaccine Works With One Shot, and Within 10 Days, Study Finds

Protection Occurs in 10 Days, Study Finds

Washington Post Staff Writer
Friday, September 11, 2009

The swine flu vaccine appears to work for adults with just one shot and within 10 days, a major boost to the widespread immunization campaign that officials are planning to protect people against the first influenza pandemic in 41 years, researchers reported Thursday.

Preliminary data from an Australian study found that a single standard dose could produce an immune response in more than 96 percent of recipients, and U.S. studies indicate that the protection occurs in eight to 10 days, scientists reported. The vaccine also appeared safe.

The eagerly awaited findings mark the first results from a flurry of studies that scientists have been rushing to conduct to develop a swine flu vaccine. The findings indicate that plans to inoculate millions of Americans -- the most ambitious vaccine campaign in U.S. history -- and others worldwide could occur much more quickly and require far less vaccine than officials had feared.

"This is good news," said Anthony S. Fauci of the National Institutes of Health, which is leading the U.S. efforts to develop the vaccine. "This is very good news. If you needed two doses, that would be a major strain on vaccine supplies nationally and globally."

The Department of Health and Human Services plans to release preliminary results Friday of its vaccine studies. Fauci would not disclose any details except to say that the findings are consistent with the Australian study involving 240 patients and that they show the response occurs even more quickly -- eight to 10 days -- than the 21 days that study found.

"The NIH clinical trials results verify and corroborate the exciting results" from the Australian study, Fauci said, adding that there is no reason to suspect vaccine produced by any of the five companies making supplies for the United States would be different.

"They are really the same. The seed virus is the same. They are made the same way," said Fauci, who heads the NIH's National Institute of Allergy and Infectious Diseases. "Even though they are from different companies, you don't usually see differences from one company to another."

Results from additional studies will be needed to see whether children and other special groups need one or two doses, he added. Young children usually need two seasonal flu shots because they have not been exposed to the virus before.

The National Institutes of Health is conducting a series of studies testing the swine flu vaccine on 4,600 volunteers, including adults, children and pregnant women.

"We will hopefully get some information about kids from our trial in a couple of weeks," Fauci said.

The results from CSL Ltd. in Australia will be published in the New England Journal of Medicine but were released online Thursday because of their urgency. The study involved a standard dose of 15 micrograms of vaccine and found that the vaccine produced a strong immune response in more than 96 percent of the subjects.

"The concern that people had was that because this was a new virus that this would require two doses for everyone. That would have created a problem of supply," Fauci said. "This greatly alleviates the problem."

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