HIV vaccine reduces infection rate by a third, study shows

An experimental vaccine against HIV has resulted in the number of people infected with the virus being a third less than in the placebo group, although the number of cases was small, in results released this week from the first trial to show that vaccination can protect against HIV infection in humans.

The phase III trial randomised 16 402 volunteers (aged 18-30) in Thailand to the HIV vaccine or placebo. The volunteers were HIV negative at the start of the trial and were all counselled on protecting themselves against HIV infection before the study and then every six months, for a total of three years.

The proof of concept study, which began in 2003, was designed to evaluate the vaccine’s efficacy in preventing …