Federal health advisers recommended Tuesday that the government approve the first bird flu vaccine as a stopgap measure, despite evidence it wouldn't protect most people.
In separate votes, the outside panel said the vaccine was both safe and effective. A vaccine must meet both standards to win FDA approval. The votes came after Food and Drug Administration officials said the Sanofi Aventis vaccine still could play an important role in protecting against the increased likelihood of a pandemic, despite its limited effectiveness.
The FDA isn't required to follow the advice of its advisory committees, but usually does. The vaccine is the first against the H5N1 influenza strain to seek government approval.
The vaccine already is being stockpiled, even without FDA approval, for eventual interim use to protect emergency workers and others in a pandemic. It would be used until better vaccines could be developed. Though not required, FDA approval would state the agency's opinion on the vaccine's safety and effectiveness, said Dr. Jesse Goodman, FDA's chief of biologic products.
In a clinical trial, the two-shot series appears to provide protection to just 45% of adults who received the highest dose. An earlier, interim analysis of the same study had suggested it prompted a protective immune response in 54% of patients, when measured 28 days after getting the second of two shots. The FDA said it would like to see a response in at least 70% of those vaccinated against bird flu.
"The more antibodies, the better. But even at lower levels, there is a possibility of protection," Goodman told reporters on the sidelines of the meeting.
The government plans to buy and stockpile enough bird flu vaccine for 20 million people, including emergency and health care workers. The Sanofi vaccine wouldn't be sold commercially.
Despite its limited effectiveness, the vaccine still could prove better than nothing in an outbreak, said Norman Baylor, director of the vaccine office at the FDA.
"The benefit of having a licensed vaccine against a potential pandemic influenza virus strain must be weighed against the risk of having no vaccine at the time of an inevitable influenza pandemic," Baylor told the panel of experts. Baylor also said even a single dose of the two-shot vaccine could help combat the deadly bird-flu strain called H5N1.
The Paris-based company believes the benefits of the vaccine outweigh its risks.
The FDA said the vaccine is safe but it remains unclear whether it's effective.