Dramatic drop in HIV infections halts circumcision trials

Men who are circumcised have about half the risk of acquiring HIV infection through vaginal intercourse as do men who are uncircumcised. Two randomised controlled trials in Uganda and Kenya, conducted with the support of the US National Institutes of Health (NIH), reached that conclusion during interim analysis by a data safety monitoring committee. The trials were stopped early, and the announcement came on 13 December.

The committee determined that the reduction in risk of acquiring HIV was 48% in Uganda and 53% in Kenya. The trials validate what was seen in a similar trial conducted in South Africa that was likewise stopped early when interim analysis in 2005 found that circumcision reduced female to male transmission of HIV by at least 60%.

All three trials enrolled adult volunteers who wanted to be circumcised and randomised them to undergo the procedure immediately or after two years. All participants were …