Circumcision shown to significantly reduce the rate of HIV infections among heterosexual men

The peer-reviewed results of the first trial of the effect of male circumcision on HIV infection, which some experts call "a landmark trial," will be published in PLoS Medicine on October 25. The trial found that circumcision reduced the rate of new infections among heterosexual men in South Africa by about 60%.

Because HIV infection rates are generally lower among African groups where circumcision is a traditional practice, compared with largely non-circumcised populations, researchers had suspected that circumcision might offer some protection against HIV transmission. However, because the lower infection rates in the circumcised groups might be due to some other difference between circumcised and uncircumcised populations, the only way to test whether circumcision has a protective effect is a randomized intervention study. Such trials are under way in Uganda and in Kenya but the trial reported in PLoS Medicine is the first to be completed, peer-reviewed, and published in a medical journal.

The large protective effect of male circumcision observed has surprised many HIV experts, and it will be important to see whether the related studies under way confirm the results of this trial.

The trial, conducted by a team of French and South African researchers and sponsored by ANRS (the French National Agency of Research on AIDS), took place in the Orange Farm area near Johannesburg, where male circumcision in adulthood is a common but not universal practice.

HIV infection is transmitted primarily through:

• Unprotected sexual intercourse;
• Transmission through contaminated blood;
• When a mother infects her baby during pregnancy, during childbirth or as a result of breastfeeding.

Transmission of HIV The researchers offered young sexually active uncircumcised heterosexual men the chance to be circumcised and then monitored for HIV infection. The participants (3,274 men) were randomly allocated to two different groups-one group was immediately circumcised and the other group was to remain uncircumcised until after the completion of the trial 21 months later. The circumcised men were instructed to abstain from sexual activity for 6 weeks after the operation. The plan was to follow the participants over 21 months, testing them for HIV at months 3, 12 and 21, to see whether there was a difference in the rate of new infections between the two groups.

After 18 months, the number of new HIV infections in the control group was 49, compared with 20 in the treatment group. The results suggested that circumcision can reduce female-to-male by about 60% (95% CI: 32%-76%).