Yes. On Sept. 15, the U.S. FDA approved four H1N1 vaccines three injectable versions and one nasal spray on the basis of early results from clinical trials involving hundreds of healthy adult volunteers that showed that the immunization was both safe and effective in activating a good immune response to H1N1. Studies with children and pregnant women are still under way, but so far both groups show no serious reactions to the vaccine.
The pandemic-flu vaccine is made the same way as the seasonal-flu shot, except with a different influenza-virus strain, so the clinical trials were not actually required for licensure the seasonal-flu shot is not tested this way each year but is considered safe. Yet health officials wanted to be cautious; the last time the government ordered a vaccine against an H1N1 virus, in 1976, 40 million Americans received the shot, and soon after, several hundred contracted Guillain-Barré syndrome, a rare but paralyzing neurological condition.
The new vaccine has no such problems so far, and nearly 80% of all inoculated people produce enough antibodies to protect them from getting sick.