Two circumcision studies halted after circumcised men's HIV risk halved

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The US National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), has halted two randomised clinical trials of adult male circumcision because an interim review of trial data revealed that medically performed circumcision reduced a man’s risk of acquiring HIV through heterosexual intercourse by around 50% in each study.

The trial in Kisumu, Kenya, of 2,784 HIV-negative men showed a 53 percent reduction of HIV acquisition in circumcised men relative to uncircumcised men, while a trial of 4,996 HIV-negative men in Rakai, Uganda, showed that HIV acquisition was reduced by 48 percent in circumcised men.

The findings reinforce the message of a South African study halted in early 2005 after researchers from the French Agence Nationale de Recherches sur le Sida (ANRS) found a 60% reduction in the risk of acquiring HIV over 21 months of follow-up in men who were circumcised at the beginning of the study (click here for full report).


voluntary male medical circumcision (VMMC)

The surgical removal of the foreskin of the penis (the retractable fold of tissue that covers the head of the penis) to reduce the risk of HIV infection in men.


The surgical removal of the foreskin of the penis (the retractable fold of tissue that covers the head of the penis) to reduce the risk of HIV infection in men.


The Joint United Nations Programme on HIV/AIDS (UNAIDS) brings together the resources of ten United Nations organisations in response to HIV and AIDS.


A patient’s agreement to take a test or a treatment. In medical ethics, an adult who has mental capacity always has the right to refuse. 

informed consent

A patient’s agreement to continue with a clinical trial, a treatment or a diagnostic test after having received a full written or verbal explanation of the risks, benefits and the possible alternatives. 

Researchers had previously noted significant variations in HIV prevalence that seemed, at least in certain African and Asian countries, to be associated with levels of male circumcision in the community. In areas where circumcision is common, HIV prevalence tends to be lower; conversely, areas of higher HIV prevalence overlapped with regions where male circumcision is not commonly practiced.

These observations led to the establishment of large clinical trials in African men to test whether performing circumcision on adult males would reduce their subsequent risk of HIV infection.

Both trials randomised adult, HIV-negative heterosexual male volunteers either to be circumcised by a medical profesisonal at a clinic, or to no intervention (no circumcision). All participants were extensively counselled in HIV prevention and risk reduction techniques.

Both trials reached their enrollment targets by September 2005 and were originally designed to continue follow-up until mid-2007. However, at the regularly scheduled meeting of the NIAID Data and Safety Monitoring Board (DSMB) on December 12, 2006, reviewers assessed the interim data and deemed medically performed circumcision safe and effective in reducing HIV acquisition in both trials. They therefore recommended the two studies be halted early. All men who were randomised into the non-intervention arms will now be offered circumcision.

“It is critical to emphasise that these clinical trials demonstrated that medical circumcision is safe and effective when the procedure is performed by medically trained professionals and when patients receive appropriate care during the healing period following surgery,” notes Dr. Fauci.

“These findings are of great interest to public health policy makers who are developing and implementing comprehensive HIV prevention programs,” National Institutes of Health director Dr Elias A. Zerhouni said today. “Male circumcision performed safely in a medical environment complements other HIV prevention strategies and could lessen the burden of HIV/AIDS, especially in countries in sub-Saharan Africa where, according to the 2006 estimates from UNAIDS, 2.8 million new infections occurred in a single year.”

An analysis using data from UNAIDS and the South African study published earlier this year estimated that if the full effect seen in the South African study were to be replicated when circumcision is taken up widely, three million HIV infections could be averted in Africa by 2026.

The World Health Organization and UNAIDS announced today they will rapidly convene a consultation to examine the results of these trials to date and their implications for countries, particularly those in sub-Saharan Africa and elsewhere with high HIV prevalence and low male circumcision levels.

Circumcision is less common in eastern and southern Africa, although there are significant local variations. Some countries, such as Lesotho, have already begun investigating the feasibility of offering circumcision to adult males and have found a high level of demand.

It is anticipated that news of these results will heighten interest in male circumcision from governments, non-governmental institutions, and the general public in a number of countries, in addition to increasing demand for male circumcision services.

WHO said today: “Countries or health care institutions which decide to offer male circumcision more widely as an additional way to protect against HIV infection must ensure that it is performed safely by well-trained practitioners in sanitary settings under conditions of informed consent, confidentiality, risk reduction counselling and safety.”

“These countries or institutions must also ensure that male circumcision is promoted and delivered in a culturally appropriate manner and that sufficient and correct information on the continuing need for other HIV prevention measures is provided. This will be necessary to prevent people from developing a false sense of security and, as a result, engaging in high risk behaviours which could negate the protective effect of male circumcision.”