First vaccine against avian flu gets US approval

The first vaccine against avian flu won US government approval yesterday, even as federal officials conceded its usefulness in a flu pandemic might be limited.

The first vaccine against avian flu won US government approval yesterday, even as federal officials conceded its usefulness in a flu pandemic might be limited.

The vaccine, made by Sanofi Pasteur, is directed against the H5N1 strain of influenza virus, which some public health experts say could possibly spark a deadly epidemic of flu in humans.

The federal government has already stockpiled enough of the vaccine to treat 6.5 million people. But yesterday’s approval by the US Food and Drug Administration means the vaccine is no longer considered experimental and, therefore, could be dispensed during a pandemic without requiring each recipient to sign a form giving informed consent.

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The vaccine, approved for adults 18 to 64, will not be available for sale to the general public. It will be dispensed only by the government in the event of a pandemic under rules that have yet to be fully worked out.

However, the vaccine has several shortcomings. It is expected to protect only about 45 per cent of people who get it. Moreover, achieving even the 45 per cent rate of protection requires two injections 28 days apart, which could also slow the response during a fast-moving flu outbreak.

It also requires high doses, limiting the number of injections that could be produced during a pandemic. The two injections combined contain 180 micrograms of antigen. By contrast, a conventional shot contains 45 micrograms of antigen: 15 micrograms for each of the three strains it protects against.

Norman Baylor, head of the vaccine office at the Food and Drug Administration, said the new vaccine was an “interim measure”.