Male medical circumcision reduced the risk of HIV acquisition by 91% in gay and bisexual men who predominantly took the insertive role in anal intercourse, a randomised study carried out in China has reported.
Studies in eastern and southern Africa have shown that undergoing male medical circumcision reduces the risk of acquiring HIV during sex between men and women by approximately 60%. Around 27 million men have undergone voluntary circumcision since 2007 in eastern and southern Africa, after the World Health Organization and UNAIDS recommended the procedure as a core element of national HIV prevention strategies for countries with high HIV prevalence.
But its utility as a prevention strategy for gay and bisexual men has been unclear, partly due to the lack of evidence from randomised trials.
A meta-analysis of 62 observational studies found that being circumcised reduced the risk of HIV acquisition for gay and bisexual men by 23%. When the analysis was restricted to studies carried out in low- or middle-income countries, being circumcised was shown to reduce the risk of acquiring HIV by 42%. Being circumcised did not reduce the risk of acquiring HIV for gay and bisexual men in high-income countries.
The authors of the meta-analysis suggested that one reason for the benefit of circumcision being confined to low and middle-income countries was role stability – a greater tendency among gay and bisexual men in low- and middle-income countries to stick with either the insertive ('top') or receptive ('bottom') role in anal intercourse.
However, another explanation for the difference is that men in high-income countries had access to a wider variety of prevention options, including consistent access to condoms, diagnosis and treatment of sexually transmitted infections, and crucially, greater coverage of antiretroviral treatment leading to lower population viral load and consequently, a lower risk of acquiring HIV. The growing availability of PrEP since 2014 would also offset any disadvantage of being uncircumcised.
Aware of these potential limitations, Chinese researchers wanted to know whether male medical circumcision reduced the risk of HIV acquisition for men who were predominantly ‘top’ in anal sex in a setting where access to PrEP and post-exposure prophylaxis (PEP) is very limited due to cost and lack of provision.
They designed a randomised trial to test the intervention. The study recruited gay and bisexual men who reported that they had predominantly taken the insertive role during anal intercourse in the past six months and had at least two male sex partners in the same period.
Participants were assigned to either immediate medical circumcision or circumcision deferred for 12 months. Participants were required to arrange circumcision at a high-quality medical facility and were subsequently reimbursed for the procedure. Participants were accompanied to the hospital for surgery and counselled on post-surgery wound care. They were advised to abstain from sexual activity for six weeks to allow full healing and were then followed for 12 months. In the deferred circumcision group, follow-up began immediately after completing a baseline survey.
Participants were not offered PrEP because it was not recommended in Chinese guidelines and studies of PrEP in China were still taking place when this study started.
Participants underwent HIV rapid testing every three months during the follow-up period and provided blood samples for laboratory HIV antibody testing after six and 12 months.
Between 2020 and 2022, 247 participants were randomised to immediate or deferred circumcision. Those in the intervention group had a median age of 28 years, 71% had a college education and 16% described themselves as bisexual. Just under a third were married or living with a male or female partner, 48% reported anal intercourse with at least five male sex partners in the past six months and almost all (92%) reported that at least 90% of their sexual encounters involved insertive anal intercourse.
Almost half (48%) were inconsistent or non-condom users during insertive anal intercourse and 39% were inconsistent or non-condom users during receptive anal intercourse. Use of PrEP or post-exposure prophylaxis (PEP) was rare; only three percent had used PrEP, and no one reported using PEP.
Participants were responsible for arranging a medical circumcision appointment. Approximately a quarter underwent circumcision within 48 hours of assignment to the immediate circumcision group, two-thirds had been circumcised after one week and 88% after one month. Four participants in the immediate circumcision group withdrew and five did not undergo circumcision during the 12-month follow-up period.
The primary study outcome was HIV acquisition during the 12-month follow-up period. During the follow-up period, five men in the control group acquired HIV, an incidence of 4.1 infections per 100 person-years. In contrast, no participant in the immediate circumcision group acquired HIV. The efficacy of circumcision for preventing HIV acquisition was 91% (p=0.0029). The researchers calculated that one HIV infection was prevented for every 25 men who were circumcised.
Men in the intervention group were much more likely to report condom use during receptive anal intercourse in the follow-up period than men in the control group (hazard ratio 0.14), a difference that was not evident in the six months prior to randomisation. Why circumcision should have affected condom use in this way is unclear. No other differences in self-reported sexual behaviour between study arms were observed.
The study authors say that HIV incidence in the control group was lower than expected when the study was planned, probably due to the lack of opportunities for sexual encounters during the prolonged period of COVID-19 pandemic restrictions in China.
The researchers say that their findings confirm what has already been found in observational studies in low- and middle-income countries. They say that global and national policymakers should now consider investing in voluntary male medical circumcision programmes for gay and bisexual men. However, it is worth noting that PrEP has similar effectiveness to medical circumcision in gay and bisexual men and protects men regardless of role in anal intercourse.
Gao Y et al. Efficacy of voluntary medical male circumcision to prevent HIV infection among men who have sex with men. A randomized controlled trial. Annals of Internal Medicine, published online 28 May 2024.