Mixed Results from Experimental Bird Flu Vaccine
ALEX CHADWICK, host:
This is DAY TO DAY from NPR News. I'm Alex Chadwick.
MADELEINE BRAND, host:
And I'm Madeleine Brand. It turns out that an experimental vaccine the government has been stockpiling in case of a bird flu outbreak isn't that effective. It protects only about half of the people who are vaccinated, and those people need a huge dose. NPR's Richard Knox reports on these findings published in the New England Journal of Medicine.
RICHARD KNOX reporting:
Flu experts knew the gist of the bad news months ago, but they're just beginning to grasp the full implications. Dr. John Treanor of the University of Rochester led the federally financed study. It involved 451 adults who got various doses of the vaccine. Treanor summarizes the findings.
Dr. JOHN TREANOR (Professor, Medicine M & D, Infectious Disease Unit, University of Rochester): Slightly more than half the subjects developed antibody levels that we think would be protective against bird flu.
KNOX: That's not very good.
Dr. TREANOR: To put that in perspective, we recognize that these are lower response rates than you might see with a conventional influenza vaccine in healthy adults.
KNOX: The conventional flu vaccine protects 70 to 90% of healthy adults from infection. Judging from the antibodies generated by the bird flu vaccine, it protects far fewer people and it took two shots and 12 times more active ingredient. That's disappointing Treanor says, but it's important to know.
Dr. TREANOR: Now we know that it's going to be a long road. This gives us a road map to move forward. So, we're not there yet, but we're making progress.
KNOX: The most immediate implication is that the current U.S. stockpile of the bird flu vaccine won't protect many people. Federal officials thought they'd ordered enough for 20 million people. The study results have shrunk that to 4 million. And the vaccine's low effectiveness means the stockpile would end up actually protecting only two million Americans against the bird flu that first arose in Asia.
Dr. GREGORY POLAND (Chief, Mayo Vaccine Research Group; Associate Chair for Research, Department of Internal Medicine, Mayo Clinic & Foundation, Rochester, Minnesota): It's nowhere near what we would need.
KNOX: Dr. Gregory Poland is director of vaccine research at Mayo Clinic College of Medicine.
Dr. POLAND: If we devoted the world's entire manufacturing capacity to making this vaccine, we would still only protect somewhere under one percent of the world's population, so clearly, this vaccine in this formulation will not be the answer.
KNOX: The answer ultimately may come from dozens of ongoing research projects aimed at finding a stronger and easier-to-manufacture bird flu vaccine. But Dr. Anthony Fauci, the government's top infectious disease expert, says those approaches are years away from application.
Dr. ANTHONY FAUCI (Director, National Institute of Allergy and Infectious Diseases, National Institutes of Health): They're really far from primetime. The immediate primetime is how do we have the vaccines that we know now are usable? How do we get to produce it better and how to we get away with less of a dose?
KNOX: When vaccine experts want to get more bang out of a given amount of vaccine, they adds something called an adjuvant. It stimulates the immune response. And that's what they're trying to do now with the low-potency bird flu vaccine. The problem is that the only approved adjuvant in this country may only lower the necessary amount of active ingredient by two-thirds.
Dr. FAUCHI: That, we would not accept as a definitive solution, because you still have to go lower than that.
KNOX: A lot lower. Meanwhile, the government has another problem. The bird flu virus that's showing up in Europe, the Middle East, and Africa these days is a different strain than the one in the stockpiled vaccine, and scientists don't think the $250 million of stockpiled vaccine will work against the newer strain. Richard Knox, NPR News.
BRAND: And there's a Q&A on the likelihood of a bird flu pandemic at our website, NPR.org.
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