A federal advisory committee on Tuesday recommended approval of the first bird flu vaccine for humans, despite concerns about its safety and evidence that the shots won't protect most people. The panel said although the vaccine had significant shortcomings, it was safe and effective for use during a pandemic or in high-risk situations, such as military deployment to regions facing an outbreak. The government plans to buy and stockpile enough doses for 20 million people. [The] director of the FDA's vaccine office told the panel that the vaccine was a stopgap measure. There are numerous vaccines under development that are potentially better than this one," he said. The bird flu strain known as H5N1 originated in Asia. Although it rarely infects people, experts fear a mutation could make it easily transmissible, triggering a pandemic. From the start of 2003, 167 people, mostly in Asia, have died of the virus, according to the World Health Organization. In clinical trials, a two-shot series of the Sanofi vaccine provided protection in 45% of adults who received the highest dose, according to an FDA analysis this week. No serious side effects were detected among the 450 healthy adults who participated in a clinical test. However, some panel members were concerned that the trial was too small to reveal rare side effects. Some experts also worried about possible allergic reactions to the vaccine because it requires a massive dose - 12 times that of the seasonal inoculation.