Drugmaker Merck has released new data showing that volunteers who got an experimental AIDS vaccine were far more likely to get infected with the virus than those who got dummy shots.
But the new details don't answer the crucial question of whether failure of the vaccine also spells doom for many similar AIDS vaccines now in testing.
Some 3,000 people, mostly homosexual men and female sex workers, had volunteered to get the experimental vaccine or dummy shots. All were warned to protect themselves from AIDS exposure.
In September, Merck announced that it was stopping the study because the vaccine didn't work.
Researchers aren't sure why more of the vaccinated volunteers wound up getting HIV than those who got dummy shots.