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Protective effect of circumcision in MSM remains in question
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Circumcision was not significantly associated with protection against transmission of HIV or other STDs among men who have sex with men, according to findings published recently.
Researchers from the Division of HIV/AIDS Prevention at the CDC conducted a meta-analysis of 15 studies whose researchers examined the association between male circumcision and HIV or STD transmission among MSM. There were data on 53,567 men; 52% were circumcised. Researchers from eligible studies had recruited MSM as part of the study and included circumcision as a variable.
“The lack of significance in this study of MSM should not dissuade us from the importance of three major studies from Africa which clearly showed the beneficial effect of circumcision on acquisition of HIV disease in heterosexual men,” Michael Tapper, MD, director of the division of infectious diseases at Lenox Hill Hospital in New York and member of the Infectious Disease News editorial advisory board, said in an interview. ”
The advent of highly active antiretroviral therapy may have influenced the findings. There was a statistically significant association between circumcision and protection from HIV infection before the introduction of HAART. However, the association was not significant after HAART.
One possible explanation for this difference may be that MSM engaged in riskier sexual behaviors after the advent of HAART, according to the researchers. This, in turn, may decrease the effect of circumcision on transmission rates. “There has been concern that some individuals in at-risk groups such as MSM may now perceive HIV as a treatable disease and may be neglecting protective behaviors in the post-HAART era,” Tapper said.
Gregorio Millett, MPH, senior behavioral scientist in the Division of HIV/AIDS Prevention at the CDC, one of the researchers who conducted the study, said that factors influencing the results may have included “the effect of ART on viral loads, the limited number of pre-HAART studies vs. post-HAART studies or a greater proportion of men who engage in receptive rather than insertive anal sex post-HAART.”
The findings bring into contrast the effects of circumcision on transmission through vaginal intercourse vs. anal intercourse. Many researchers have indicated that further study is required to determine the nature of the protective effect of circumcision on HIV and STD transmission.
“As the CDC moves forward in determining what role circumcision may play, from a public health perspective, individuals may wish to consider circumcision as an additional HIV prevention measure,” Millett said. “However, people must recognize that circumcision has only proven effective in reducing HIV risk for infection through insertive vaginal sex. It confers only partial protection and should be considered only in conjunction with other proven prevention measures. Also, it carries risks and costs that must be considered in addition to potential benefits.”
Tangential issues
Millett said that male circumcision rates are about 77% to 80% in the United States but much lower in the African countries where the trials referenced by Tapper were conducted. Moreover, the HIV epidemic in African countries is primarily driven by heterosexual sex where there is a documented protective effect associated with male circumcision. In contrast, MSM are the main transmission group in the HIV epidemic in the United States, and the association between circumcision and HIV infection is less clear among MSM populations. “Consequently, any population effect of male circumcision in the reduction of HIV may be less in the United States than in African countries where the circumcision trials took place,” Millett said.
In the overall analysis, there also was no association between circumcision and other STDs. Stratified analyses revealed an almost significant relationship between circumcision and likelihood of acquiring an STD. However, the researchers wrote that confounding factors, including the varying modes of transmission of STDs, may have influenced these data. – by Rob Volansky
It is undisputed that in the African male heterosexual, circumcision reduced the risk for female-to-male HIV transmission. In contrast, within the MSM community, the protective value of circumcision is questionable and not clearly demonstrated, as shown in this meta-analysis. It is important to emphasize that these findings apply only to MSM and not heterosexuals. There are some tantalizing suggestions of findings that approach significance. In an accompanying editorial, Vermund et al have raised the issue of randomized controlled trials as a way of answering the question. It would be a challenging trial to carry out, but I agree that it may be the only way of reaching definitive answers.
– Theodore Eickhoff, MD
Infectious Disease News Chief Medical Editor
For more information:
- Millett G, Flores S, Marks G. Circumcision status and risk of HIV and sexually transmitted infections among men who have sex with men: a meta-analysis. JAMA. 2008;300:1674-1684.
- Vermund S, Quian H. Circumcision and HIV prevention among men who have sex with men: no final word. JAMA. 2008;300:1698-1700.