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【科普】FDA批准首个人H5N1疫苗 及禽流感科普知识
FDA approves first H5N1 vaccine for human use
By Sue Mueller
Apr 17, 2007 - 12:38:37 PM
The U.S. Food and Drug Administration today April 17 announced its first approval of a vaccine for human use in the United States against the H5N1 influenza virus, commonly known as avian or bird flu.
The vaccine, manufactured by sanofi pasteur was found to be able to develop adequate immunity against H5N1 in 45 percent of the people receiving two doses of the vaccine.
The vaccine is not intended to fully prevent bird flu infection when an influenza pandemic emerges, which may be caused by a variant that is immune to the vaccine.
Instead, the vaccine is to provide "early limited protection in the months before a vaccine tailored to the pandemic strain of the virus could be developed and produced."
"The threat of an influenza pandemic is, at present, one of the most significant public health issues our nation and world faces," said Andrew C. von Eschenbach, M.D., Commissioner of Food and Drugs.
"The approval of this vaccine is an important step forward in our protection against a pandemic."
The H5N1 virus, one version of the influenza A virus commonly found in birds, is far more severe than seasonal influenza and the infection happens quickly, with pneumonia and multi-organ failure commonly seen.
No human case of H5N1 has been reported in the United States while almost 300 people worldwide have been infected with this virus since 2003 and more than half of them have died.
Experts and the government officials fear that the current H5N1 influenza virus may someday mutate into a strain that can readily spread from person to person, potentially infecting millions of people worldwide and killing tens of hundreds.
"The timing and severity of an influenza pandemic is uncertain, but the danger remains very real," said Jesse L. Goodman, M.D., M.P.H., Director of FDA's Center for Biologics Evaluation and Research.
"We are working closely with other government agencies, global partners and the vaccine industry to facilitate the development, licensure and availability of needed supplies of safe and effective vaccines to protect against the pandemic threat."
The vaccine is made of a human strain and is intended for immunizing people 18 through 64 years of age who could be at increased risk of exposure to the H5N1 influenza virus contained in the vaccine.
To immunize people against H5N1, two injections of the vaccine approximately one month apart are needed.
The H5N1 vaccine will not be sold commercially. For the time being, the manufacturer, sanofi pasteur Inc. makes the vaccine only for the U.S. government for inclusion within the U.S. Strategic National Stockpile for distribution by public health officials if needed.
The FDA approval is based on the results of a clinical study of 103 healthy people who received two shots of 90 micrograms of the vaccine with 28 days apart. Additional 300 healthy people received two doses lower than 90 micrograms per injection and additional 48 received a placebo.
According to the study, 45 percent of individuals receiving the 90 microgram, two-dose regimen developed adequate amounts of antibodies, which are expected to reduce the risk of getting influenza.
The remaining individuals may also have some protection against bird flu and have the potential to help reduce disease severity and influenza related hospitalizations and deaths even if their antibody levels were below the optimal level.
The vaccine was well tolerated and the most common side effects include pain at the injection site, headache, general ill feeling and muscle pain.
More information on this H5N1 influenza vaccine is being collected on safety and effectiveness in other age groups and will be available to FDA in the near future.
A more potent bird flu is being developed by Sanofi Pasteur and other manufacturers with the support of FDA and the U.S. National Institutes of Health and other government agencies.
For now, the FDA approval and availability of this vaccine will enhance national readiness and the nation's ability to protect those at increased risk of exposure to H5N1 influenza virus.
The U.S. Strategic National Stockpile is maintained by the U.S. Centers for Disease Control and Prevention and large quantities of medicine and medical supplies can be delivered to any states within 12 hours.
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Questions and Answers from FDA
What is the Food and Drug Administration (FDA) announcing?
FDA is announcing the licensure of the first vaccine in the United States for humans against the H5N1 influenza virus, commonly referred to as avian influenza or "bird flu." This inactivated influenza virus vaccine is indicated for immunization of persons 18 through 64 years of age who are at increased risk of exposure to the H5N1 influenza virus subtype contained in the vaccine. This vaccine is derived from the A/Vietnam/1203/2004 influenza virus. The vaccine is manufactured by sanofi pasteur Inc. of Swiftwater, PA and has been purchased by the federal government for inclusion within the Nation's Strategic National Stockpile.
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作者:admin@医学,生命科学 2010-11-07 05:11
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