The Potential Impact of Male Circumcision on HIV in Sub-Saharan Africa

Abstract

Background

A randomized controlled trial (RCT) has shown that male circumcision (MC) reduces sexual transmission of HIV from women to men by 60% (32%−76%; 95% CI) offering an intervention of proven efficacy for reducing the sexual spread of HIV. We explore the implications of this finding for the promotion of MC as a public health intervention to control HIV in sub-Saharan Africa.

Methods and Findings

Using dynamical simulation models we consider the impact of MC on the relative prevalence of HIV in men and women and in circumcised and uncircumcised men. Using country level data on HIV prevalence and MC, we estimate the impact of increasing MC coverage on HIV incidence, HIV prevalence, and HIV-related deaths over the next ten, twenty, and thirty years in sub-Saharan Africa. Assuming that full coverage of MC is achieved over the next ten years, we consider three scenarios in which the reduction in transmission is given by the best estimate and the upper and lower 95% confidence limits of the reduction in transmission observed in the RCT.

MC could avert 2.0 (1.1−3.8) million new HIV infections and 0.3 (0.1−0.5) million deaths over the next ten years in sub-Saharan Africa. In the ten years after that, it could avert a further 3.7 (1.9−7.5) million new HIV infections and 2.7 (1.5−5.3) million deaths, with about one quarter of all the incident cases prevented and the deaths averted occurring in South Africa. We show that a) MC will increase the proportion of infected people who are women from about 52% to 58%; b) where there is homogenous mixing but not all men are circumcised, the prevalence of infection in circumcised men is likely to be about 80% of that in uncircumcised men; c) MC is equivalent to an intervention, such as a vaccine or increased condom use, that reduces transmission in both directions by 37%.

Conclusions

This analysis is based on the result of just one RCT, but if the results of that trial are confirmed we suggest that MC could substantially reduce the burden of HIV in Africa, especially in southern Africa where the prevalence of MC is low and the prevalence of HIV is high. While the protective benefit to HIV-negative men will be immediate, the full impact of MC on HIV-related illness and death will only be apparent in ten to twenty years.

Editors' Summary

Background.

Africa is the continent most affected by HIV/AIDS, and it is important to consider all possible means of reducing the spread of HIV infection. Male circumcision has been a tradition in many parts of Africa for hundreds of years. Boys who are circumcised usually have it done in late childhood or their early teenage years. It was noticed some years ago that those African groups in which circumcision is routinely done on all boys have fewer cases of HIV/AIDS than are found in groups where circumcision is not a tradition. This finding gave rise to the idea that circumcision might give a degree of protection against HIV, though it was recognised that some other, unknown difference between these groups of people might actually be the important factor. In 2005 a trial was reported from the Orange Farm area of South Africa, in which uncircumcised men were offered the chance to be circumcised. The men who agreed were divided at random into those who had the operation straightaway and those who were to have it two years later. During the next 18 months, the number of new cases of HIV infection was much higher amongst the men who had not been circumcised. Circumcision did therefore seem to offer a measure of protection against infection. This protective effect was estimated at being about 60%. Similar trials are under way in other parts of Africa but there are no results available from them at this stage.

Why Was This Study Done?

If the level of effectiveness of circumcision suggested by the South African trial is correct, then, as one part of a range of measures to reduce the spread of HIV, it would seem logical to encourage the practice of male circumcision. It would be useful to have an estimate of just how many new cases could be prevented and how many lives would be saved by the promotion of male circumcision. Calculations would have to allow for various factors, such as the present level of HIV infection, which varies from one country to another, and the fact that many men are already circumcised.

What Did the Researchers Do and Find?

This research did not involve collecting any new data. The researchers used mathematical modelling to make calculations. They based their model on data from the Orange Farm trial and on information from various sub-Saharan African countries on the proportion of men who are circumcised and the proportion who are HIV-positive. They made the assumption that if circumcision is intensively promoted, all men in those countries will be circumcised in 10 years time. They calculated the number of new cases that would be prevented and the lives that would be saved in ten years, 20 years, and 30 years time. Their best estimate is that with the promotion of male circumcision, two million cases and 0.3 million deaths will be avoided in ten years time. Over the following ten years, according to the researchers' model, a further 3.7 million cases and 2.7 million deaths would be prevented. Most of the initial impact would be in men, but the reduction in the number of HIV-positive men would in time also lower the risk of women becoming infected. Overall, on the basis of these calculations, male circumcision would reduce the rate of infections by about 37%—both female-to-male and male-to-female transmission. The size of the impact would vary from one country to another; it would be greatest in southern Africa where HIV infection rates are high and circumcision rates relatively low compared with the rest of sub-Saharan Africa.

What Do These Findings Mean?

Male circumcision alone cannot bring the HIV/AIDS epidemic in Africa under control. Even circumcised men can become infected, though their risk of doing so is much lower. However, the researchers call for the promotion of male circumcision to become a major part of AIDS control programmes. Their results are based on the findings of just one study (the Orange Farm trial), and it will be important to repeat the calculations when further studies have been completed.

Additional Information.

Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030262:

• The Orange Farm trial was published in PLoS Medicine. Several articles discussing the trial were also published in the same issue of the journal

• The Joint United Nations Programme on HIV/AIDS (UNAIDS) has information about the state of the HIV/AIDS epidemic and prevention strategies worldwide. It produces an annual report and has documents on a wide range of topics

•  AEGIS is the world's largest searchable database on HIV and AIDS.

• Many organizations provide information on AIDS prevention—for example, the Terrence Higgins Trust

• The World Bank's Global HIV/AIDS Program has a report about male circumcision and HIV infection

Abstract

A modelling study, based on one trial plus national figures for current prevalence of HIV and of male circumcision (MC), found increasing MC in Africa could produce major fall in HIV prevalence in 10-12 years.