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.

Figure 1. The Relationship between the Prevalence of HIV and MC in Sub-Saharan Africa

The percent prevalence of HIV [ 12] is plotted on a logarithmic scale against the estimated proportion of adult men who are circumcised [ 32, 33]. Green, southern Africa; red, East Africa; orange, Central Africa; blue, West Africa. C, Central Africa; E, East Africa; S, South Africa; W, West Africa. ANG, Angola; BEN, Benin; BOT, Botswana; BUF, Burkina Faso; BUR, Burundi; CAM, Cameroon; CAR, Central African Republic; CHA, Chad; CON, The Congo; DJI, Djibouti; DRC, Democratic Republic of the Congo; EQA, Equatorial Guinea; ERI, Eritrea; ETH, Ethiopia; GAB, Gabon; GAM, Gambia; GHA, Ghana; GUB, Guinea Bissau; GUI, Guinea; IVO, Côte d'Ivoire; KEN, Kenya; LES, Lesotho; LIB, Liberia; MAL, Mali; MAU, Mauritania; MAW, Malawi; MOZ, Mozambique; NAM, Namibia; NIA, Nigeria; NIR, Niger; RWA, Rwanda; SEN, Senegal; SIE, Sierra Leone; SOA, South Africa; SOM, Somalia; SUD, Sudan; SWA, Swaziland; TAN, Tanzania; TOG, Togo; UGA, Uganda; ZAM, Zambia; ZIM, Zimbabwe.

Figure 2. The Geographical Distribution of MC, HIV Prevalence, and the Potential Reduction in HIV Incidence if All Men Were Circumcised

(A) Proportion of men who are circumcised, χ (%). (B) Prevalence of HIV in 2003, P (%). (C) Potential impact of MC on the incidence of HIV infection, Δ J (% per year), calculated using Equation 1. (D) Potential reduction in the number of new adult infections each year Δ JN, where N is the adult population (thousands per year). The incidence, J, is taken to be one-tenth of the prevalence, P. The data on which these maps are based are given in Table 1. Disclaimer: The designations used and the presentation of material in Figure 2 do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city, or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Figure 3. Time Trends in the HIV Incidence, Prevalence, and Related Mortality in South Africa if the Proportion of Circumcised Men Remains Constant or Is Increased to Full Coverage (over Five or Ten Years)

(A) HIV incidence (B) HIV prevalence (C) HIV-related mortality in South African adults assuming that full coverage of MC is reached in 2015. The model is fitted to the blue data points in (B). (D–F) Repeat (A–C) but assuming that full coverage is reached in 2010 (see Protocol S1). The blue lines give the projected values excluding the impact of MC or other additional interventions. The red, green, and pink lines give the projected values assuming that MC reduces female-to-male transmission by 32%, 60%, and 76%, respectively, corresponding to the estimated reduction and 95% confidence intervals observed in the RCT of MC [ 9]. On all graphs, the blue boxes on the left mark the period 2005 to 2015, the blue boxes on the right mark the period 2015 to 2025.