The Food and Drug Administration (FDA) of the US has granted approval to a French drug firm for manufacturing the first bird flu vaccine. However it says it is only an interim measure and it is looking for more potent drugs.
The U.S. Foood and Drug Administration (FDA) has approved the first vaccine designed to protect humans against the H5N1 influenza virus, or the bird flu. It is a product of the Paris-based Sanofi-Aventis, the world's third largest drug-maker.
At least 291 people worldwide have been infected with the virus since 2003, and 172 have died, according to the World Health Organization.
The new vaccine will not be sold commercially. It is being stockpiled by the government for use if the H5N1 bird flu virus mutates to a form that can spread easily from person to person.
If it acquires the ability to pass person-to-person easily, it would spark a pandemic and scientists fear it could kill tens of millions of people.
The FDA said two injections given 28 days apart may provide "limited" protection if a pandemic occurs. About 45 percent of people who got the vaccine in a study developed an immune response to the virus.
The vaccine is "sort of an interim measure" until better ones are developed, said Norman Baylor, director of the FDA's Office of Vaccines Research and Review. Several companies are working on other versions.
"Ideally, yes, you would like a vaccine that would have a higher efficacy," Baylor told reporters.
A single shot and a lower dose also would be preferred, Baylor said. The dose needed for the new Sanofi vaccine is higher than used in the seasonal flu vaccine.
Still, "we feel as part of pandemic preparedness it would be best to have a licensed vaccine. Our review suggests this vaccine is safe and effective," Baylor said.
David Williams, president of Sanofi vaccine unit Sanofi Pasteur, said in a statement the approval was "a significant milestone in pandemic preparedness."
Sanofi manufactures the vaccine at a plant in Swiftwater, Pennsylvania.
Philip Hosbach, vice president for immunization policies and government affairs for Paris-based Sanofi, said the company was working to develop ways to make its vaccine more potent.
The U.S. Department of Health and Human Services said it had already purchased 13 million doses of the Sanofi vaccine, enough to inoculate 6.5 million people.
The vaccine was approved for people age 18 to 64. Studies in other age groups are ongoing. The most common side effects reported were pain at the injection site, headache, "general ill feeling" and muscle pain, the FDA said.
Clearance from the FDA will save doctors, hospitals and regulators hours, if not days, that would otherwise be needed to gain permission to use Sanofi's shot in a pandemic, said William Schaffner, a Vanderbilt University infectious disease specialist who advises the U.S. government on vaccines.
The vaccine would be given in two 90-microgram shots, about a month apart. Seasonal flu shots normally require about 15 micrograms of viral protein for each strain they protect against.
The U.S. has awarded contracts for a smaller number of shots to Novartis AG, based in Basel, Switzerland, and Glaxo SmithKline Plc of London.
Glaxo is developing an H5N1 vaccine using a booster, called an adjuvant, which makes its shot effective in two doses of 3.75 micrograms, almost 25 times smaller than Sanofi's.