Observational research

Early evidence that male circumcision might help protect men from HIV came from studies that observed associations between circumcision status and the prevalence of HIV infection.1,2

Since the late 1980s, epidemiologists have carefully examined the characteristics of populations with high rates of HIV infection. Several of these ecologic studies reported low prevalence of male circumcision in the parts of sub-Saharan Africa most affected by the epidemic.3,4 An analysis of data on male circumcision and HIV prevalence across 118 developing countries reported similar findings.5 In contrast, data from Demographic and Health Surveys show that within countries, HIV prevalence is not always lower among circumcised men.67

A review of 28 observational studies in African countries concluded that circumcised men had about a 44 percent lower risk of HIV infection compared to circumcised men. Among men at highest risk for HIV, the risk of acquiring the virus was 71 percent lower if they were circumcised.8

Similar results were seen in another systematic review that included 37 studies from countries in sub-Saharan Africa and other regions of the world. This review found a strong association between circumcision and reduced rates of HIV acquisition in the 19 studies that were conducted among high-risk populations.9

However, these observational studies could not definitively establish that circumcision was protecting men from HIV infection. Another possible explanation is that practices associated with religion or culture reduced the men's risk of HIV. But the observational evidence was compelling, and it provided the rationale for conducting three randomised controlled trials of male circumcision for HIV prevention.

No clinical trials have tested whether circumcision reduces HIV risk among men who have sex with men, and observational studies have yielded mixed results. Male circumcision appeared to have a protective effect in several studies among men who have sex with men in the United States,10,11 and results from Peru suggest that circumcision may confer some protection against HIV to men who engage exclusively in insertive anal sex.12 But other studies among men who have sex with men in the United States13 and Australia14 found no reduced risk associated with circumcision overall or among insertive partners. An analysis of the data from 18 observational studies among men who have sex with men found no evidence that male circumcision protects them against HIV or other sexually transmitted infections.15



  1. Alcena V. AIDS in third world countries. NY State J Med 1986;86(8):446.

  2. ​​Fink AJ. A possible explanation for heterosexual male infections with AIDS. N Engl J Med 1986;315(18):1167.

  3. Moses S, Bradley JE, NagelKerke JD, et al. Geographical patterns of male circumcision practices in Africa: association with HIV seroprevalenceInt J ​Epidemiol 1990;19(3):693-697.

  4. Halperin DR, Bailey RC. (Preview only) Male circumcision and HIV infection: 10 years and countingLancet 1999;354(9192):1813-1815.

  5. Drain PK, Halperin DT, Hughes JP, et al. Male circumcision, religion and infectious disease: an ecologic analysis of 118 developing countriesBioMed Central 2006;6:172-182.

  6. Garenne M. Male circumcision and HIV control in AfricaPLoS Med 2006;3(1):e78.

  7. Mishra V, Hong R, Khan S. Risk behaviors and patterns of HIV seroprevalence in countries with generalized epidemics: results from the Demographic and Health Surveys. American Public Health Association 134th Annual Meeting and Exposition, Boston, MA, USA, 4-8 November 2006.

  8. Weiss HA, Quigley MA, Hayes RJ. Male circumcision and risk of HIV infection in sub-Saharan Africa: a systematic review and meta-analysisAIDS 2000 2014;(15):2361-2370.

  9. Siegfried NJ, Mueller M, Deeks J, et al. HIV and male circumcision - a systematic review with assessment of the quality of studiesLancet Infect Dis 2005;5(3):165-173.

  10. Buchbinder SP, Vittinghoff E, Heagerty PJ, et al. Sexual risk, nitrate inhalant use, and lack of circumcision associated with HIV seroconversion in men who have sex with men in the United States. J Acquir Immune Defic Syndr 2005;39(1):82-89.

  11. Kreiss JK, Hopkins SG. (Abstract only) The association between circumcision status and human immunodeficiency virus infection among homosexual menJ Infect Dis 1993;168(6):1404-1408.

  12. Guanaria J, Lama JR, Goicochea P, et al. How willing are gay men to "cut off" the epidemic? Circumcision among MSM in the Andean region. Fourth International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention, Sydney, Australia, 22-25 July 2007.

  13. Millett G, Ding H, Lauby J, et al. Circumcision status and HIV infection among black and Latino men who have sex with men in 2 US cities. J Acquir Immune Defic Syndr 2007;46(5):643-650.

  14. Templeton DJ, Jin F, Prestage GP. Circumcision status and risk of HIV seroconversion in the HIM cohort of homosexual men in Sydney. Fourth International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention, Sydney, Australia, 22-25 July 2007.

  15. Millett GA, Flores SA, Marks G, et al. Circumcision status and risk of HIV and sexually transmitted infection among men who have sex with men. JAMA 2008;300(14):1674-1684.