Bird flu vaccine eggs all in one basket
Researchers: Not sure shots will work but it's all they've got
By Caleb Hellerman
Robert Webster has spent more than 50 years trying to outsmart influenza viruses.
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(CNN) -- In a handful of warehouses, at secret locations in the United States, sit containers of vaccine that health officials fervently hope could head off an outbreak of the killer flu.
Citing national security, the Department of Health and Human Services won't say where the vaccine is being stored, but last week the National Institutes of Health said that by February, 7.8 million doses of vaccine that could be used against the H5N1 strain of bird flu would be available. Since two shots, a month apart, are give to each person, this would provide coverage for 3.9 million Americans.
Those doses are the first of the President Bush's announced plan to stockpile enough vaccine to innoculate at least 20 million.
Since September, the Department of Health and Human Services has signed contracts worth more than $160 million with vaccine giants Sanofi Pasteur and Chiron.
The experimental vaccine against H5N1 was developed by Robert Webster of St. Jude's Children's Research Hospital in Memphis, Tennessee. He has spent more than 50 years trying to outsmart influenza viruses.
Creating this vaccine was particularly difficult because making it -- like all flu vaccines -- requires the virus to be grown in chicken eggs. H5N1 proved lethal to the eggs.
To get around that obstacle, Webster and his colleagues used a process called reverse genetics. They extracted the portion of the gene that made H5N1 so virulent, while leaving the rest of the virus intact. The resulting virus was no longer so lethal, but in clinical trials, it still stimulated the immune system to produce a strong protective response to the original strain.
Would Webster's vaccine work against the slightly different strain? Even he said he isn't sure.
"I think the vaccine would give you partial protection. It would probably protect you from death," Webster said. "You would probably get very sick but not die."
The vaccine targets the current H5N1 virus circulating in Asia, which decimates chicken flocks but which does not circulate easily among people, or even from birds to people.
A pandemic strain, by definition, would involve a virus that had mutated to spread easily from person to person.
Webster points out that H5N1 is a strain that has never before circulated among humans, meaning that no one has any natural immune protection -- as opposed to the partial protection people have against the slightly different strains of flu virus that circulate every year. Since people lack any natural protection, a vaccine that's only partially effective could still save millions of lives.
Even if the vaccine proves totally effective, you won't be able to head to your doctor's office for a shot. The FDA has yet to approve the vaccine. The full U.S. order is only enough to inoculate at most one in 14 Americans.
Given the shortfall, government officials have a plan to prioritize who gets the shots.
According to the government's pandemic flu plan, first in line would be health care workers and those involved in vaccine manufacture. Groups prone to complications, including those older than 65 or younger than 6 months, would be next in line.
In addition, 2.2 million of the first 8 million doses are reserved for the military, according to Dr. Anthony Fauci of the National Institutes of Health.
Researchers are working on ways to stretch the vaccine supply -- for example, testing additives that would make a smaller dose more effective. And several companies are working with technology that would not require chicken eggs and could produce vaccine in much less time than the four to six months now required.
But for now, Americans are stuck with chicken eggs and a vaccine that may or may not work.
"What's killing chickens now is H5N1, and that's what we're basing our future on right now," says former Health and Human Services Secretary Tommy Thompson, who works for private companies as a consultant on health care matters. "I mean, it's just nuts."
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