Circumcision reduces HIV incidence in Ugandan men and herpes prevalence in South Africans

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The 19th Conference on Retroviruses and Opportunistic Infections (CROI) heard this week that a tenfold increase in medical male circumcision (MMC) in non-Muslim men in the Rakai district of Uganda has led to a 28% fall in HIV incidence since MMC was made widely available. Incidence in Muslim men, who are all circumcised and had a lower incidence rate in the first place, did not fall during the same period, so this fall appears to be a consequence of circumcision. No comparable fall (or rise) in HIV incidence has been seen in women so far, however, and only a third of non-Muslim men have so far become circumcised.

Another study from Orange Farm district in South Africa has found that since the roll-out of MMC in the area, the prevalence of herpes (HSV-2) is 23% lower in men who have become circumcised than ones who have not, though this is not as big a reduction as the 55% reduction in HIV prevalence seen.

Three randomised controlled trials (RCTs) of medical male circumcision as an HIV prevention measure took place in the mid-2000s and produced a reduction in HIV infections in circumcised, compared to uncircumcised, men ranging from 51% to 60%. Since 2007, programmes offering MMC to men in the areas where the RCTs happened have produced large increases in the proportion of men who are circumcised.


Ronald Gray, principal investigator in the Raki RCT, told the conference that MMC was made available in the district from 2007 onwards. The prevalence of MMC and the annual incidence of HIV infections were estimated among all non-Muslim men over a four-year period before the availability of MMC (2000 to 2003) and 5 years after its availability (2006 to 2011). HIV incidence was also estimated over the same periods in Muslim men circumcised in childhood.


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.

herpes simplex virus (HSV)

A viral infection which may cause sores around the mouth or genitals.

randomised controlled trial (RCT)

The most reliable type of clinical trial. In a trial comparing drug A with drug B, patients are split into two groups, with one group receiving drug A and the other drug B. After a number of weeks or months, the outcomes of each group are compared.


In everyday language, a general movement upwards or downwards (e.g. every year there are more HIV infections). When discussing statistics, a trend often describes an apparent difference between results that is not statistically significant. 

MMC was provided as a free, accessible service from 2007 onwards. Population surveys show that the proportion of non-Muslim men who were circumcised increased from 3.3% in 2000 to 25% in 2009 and 35% in 2011. Medical male circumcision prevalence among non-Muslim men increased from 3.3% in 2000 to 2003 to 25.3% in 2009 and 35% in 2011. Most men were getting circumcised in their early twenties, but the proportion of under-19s who were circumcised increased from 3.8% to 12.4% during the same period.

Among all non-Muslim men (circumcised and uncircumcised), HIV incidence declined from 1.4% a year in 2000-2003 to 1.0% a year in 2004-2009, a 22% fall after adjusting for population changes. This was significant (95% confidence interval 2% to 38%, p = 0.04). In Muslim men HIV incidence stayed the same, at 0.57% a year in 2000-03 and 0.46% a year in 2004-09 (p = 0.58). Annual HIV incidence in non-Muslim men is half as high in circumcised men compared to uncircumcised ones (1.1% versus 0.55%).

The researchers estimated that the ‘population attributable fraction’ in the fall in HIV incidence in non-Muslim men was 37%, meaning that there would be 37% more HIV infections in all non-Muslim men if the proportion circumcised had not increased.

There were no changes in risk behaviours among non-Muslims after the availability of medical male circumcision. The proportion of men who had had a non-marital sexual partner was 46% in 2002-03 and 42% in 2006-11 (18% and 14% respectively had two or more non-marital partners).

So far, however, there has been no significant decline in HIV incidence in non-Muslim women, though there has been a trend: incidence was 1.4% a year in 2000-03 and 1.2% in 2006-11, an 11% decline (95% confidence interval -29% to +5%, p = 0.15).

Gray commented that despite considerable publicity only a third of non-Muslim men were as yet circumcised, and said that there was an “urgent need for demand creation to increase the acceptance of medical male circumcision.”

Orange Farm

Circumcision also became generally available for free in 2007 in Orange Farm; this RCT announced its results in mid-2005 but roll-out was not started till the results from the other RCTs came through.

A presentation at last year’s IAS conference in Rome showed that the proportion of men in the community had trebled from 16% to 49% since the roll-out and that HIV prevalence in circumcised men was 55% lower.  

Two cross-sectional surveys were conducted, one in 2007, before the beginning of the roll-out, and one in 2010-11. In the 2011 survey of 3355 men randomly picked from the community, the mean age was 26. About 30% were married and 40% had children; They had had an average of 2.5 partners in the last year and 44% maintained consistent condom use. Circumcision prevalence was now 53%, and 59% in 20-24 year olds.

Compared to uncircumcised men, circumcised men were younger; more educated; more likely to be unemployed; to be of Sotho ethnicity; and to know their HIV status. There were no statistically significant differences in terms of religion or reported sexual behavior, including condom use, and alcohol consumption.

In men aged 15 to 49, HSV-2 prevalence was 31% in uncircumcised men and 16.5% in circumcised men. After adjusting for population characteristics, this equated to a 23% reduction in HSV-2 prevalence in circumcised men.

Principal investigator Bertran Auvert said that if male circumcision did not exist in the community, HSV-2 prevalence would have been 15.5% higher among all men aged 15 to 49, and 26% higher in men aged 15 to 34. “This study shows that circumcision can have a significant impact on HSV-2 infections in men in quite a short time,” he commented.

He said there were signs that awareness of the protective effect of circumcision was spreading among the community: “Our age profiles show that at first the young guys were getting circumcised, but now we see older guys getting interested in it,” he said.


Gray R et al. Population-level impact of male circumcision on HIV incidence: Rakai, Uganda. 19th Conference on Retroviruses and Opportunistic Infections, Seattle, abstract 36, 2012. The abstract is available on the official conference website.

Auvert B et al. ANRS-12126—Impact of male circumcision roll-out on HSV-2 prevalence among men: Orange Farm, South Africa. Nineteenth Conference on Retroviruses and Opportunistic Infections, Seattle, abstract 37, 2012. The abstract is available on the official conference website.

A webcast of the session HIV prevention: PrEP, microbicides and circumcision, is available through the official conference website.