Cautious optimism for an HIV vaccine

For the first time, we have reason to be hopeful about the prospects of a vaccine for HIV.

The new study was conducted in Thailand, with more than 16,000 people between ages 18 and 30 participating. They were all HIV negative at the beginning of the trial.Nearly 8,200 received a placebo and a similar number received a combination of six vaccines over six months. All were followed for three years.

“This shows a statistically significant effect,” Kim said.He cautioned that a lot more research was necessary, because the vaccine did not prevent everyone from being infected.Fifty-one people in the vaccine group eventually contracted HIV, compared with 74 in the placebo group.

via Combo vaccine reduces risk of HIV infection, researchers say – CNN.com.

Interesting, certainly, but we have a long way to go.  I’ve ranted here before about the difference between relative risk reduction and absolute risk reduction and how misleading the former can be.  Looking at these results from a relative risk reduction standpoint, a drop in infection from 74 to 51 is about 31%, which seems fairly impressive.  However, if you look at the overall infection rate, the drop is from 74 per 8,200, or 0.9%, to 51 in 8,200, or 0.6%, which is not so impressive.  Still, given the failure of previous attempts at an HIV vaccine, these results are promising, and will hopefully lead to a more effective vaccine in the future.