The first vaccine against avian flu for the United States was endorsed by a Food and Drug Administration advisory panel yesterday, but merely as a stopgap until better vaccines are developed.
The experimental vaccine, made by Sanofi-Pasteur, protected only 45 percent of the 91 people on whom it was tested. Reaching even that level of protection required 12 times the dose of antigen delivered by a typical flu shot and had to be given in two shots several weeks apart. It is based on a virus strain that was circulating in Vietnam three years ago.
Dr. Robert Couch said panel members knew of better vaccines in development, "but this is the only vaccine we had in front of us." The panel voted unanimously that the vaccine was effective enough. The FDA usually accepts recommendations from its expert panels.
The government plans to stockpile enough H5N1 vaccine to protect 20 million doctors, nurses, paramedics, lab technicians and other emergency workers. Sanofi does not plan to sell this vaccine to the public; it is developing newer ones.
The World Health Organization said 16 companies from 10 countries were developing prototype vaccines. The difficulty, experts say, is finding one that works at low doses and can be made quickly. At present, it would take months to create enough for the whole country.