JHPIEGO TrainerNews™ |
Clinical Update: Contraceptive Pearl
(June 2002)
HIV And Male Circumcision
Question: I've heard that male circumcision may provide protection against HIV infection. Is that true?
Answer: Yes, according to observational studies. A group at the London School of Hygiene and Tropical Medicine conducted a meta-analysis of 27 studies on the subject. They found an overall reduction in risk of about 50 percent (crude relative risk of 0.52). But among 15 studies that controlled for confounding factors, the protection was closer to 60 percent (adjusted relative risk of 0.42) and protection was even stronger for men considered at high risk for HIV. So the protection seems to be sizable though not complete.
Since the meta-analysis, additional compelling evidence has come from a "discordant" partner study in Rakai, Uganda. HIV seroconversion rates were compared among HIV- men with HIV+ partners, (thus to a large degree controlling for exposure to HIV). Among the uncircumcised, 40 of 137 seroconverted. However, among the 50 circumcised men, NONE seroconverted after two years.
Of course observational studies could have unknown biases that were not controlled for. Currently clinical trials are ongoing in Kenya and will start soon in Uganda, to provide more definitive evidence.
References:
- Weiss HA, Quigley MA, Hayes RJ. Male circumcision and risk of infection in sub-Saharan Africa: A systematic review and meta-analysis. AIDS 2000; 14:2361-70.
- Quinn TC et al. Viral load and heterosexual transmission of human immunodeficiency virus type 1. Rakai Project Study Group. NEJM 2001; 342:921-9.
Foreskin and HIV
Question: What is it about the foreskin that might increase risk of HIV transmission?
Answer: The interior side of the foreskin has a mucosal surface which is more susceptible to trauma than the tougher skin of the penile shaft or the glans. Moreover, the foreskin contains high levels of HIV target cells (such as Langerhan's cells). Indeed in a recent *in vitro* study of 14 foreskins, investigators from Chicago found that foreskin mucosal tissue had a 7-fold greater susceptibility to HIV-1 than cells in cervical tissue under the same conditions. Lastly, the presence of a foreskin appears to increase risk of ulcerative STDs such as chancroid and herpes, which are strong co-factors for HIV infection.
Thus there appears to be good biologic plausibility to the epidemiologic finding that male circumcision reduces risk of HIV infection.
References:
- Estrada CR et al. Biologic mechanisms of HIV infection of human foreskin: implications for transmission. Presentation at the American Urological Association, May 2002.
- Szabo R, Short R. How does male circumcision protect against HIV infection? BMJ 2000; 320:1592-1594.
- Moses S, Bailey RC, Ronald AR. Male circumcision: Assessment of health benefits and risks. Sex Transm Infect
1998;74:368-73.
These "Pearls" were prepared by Dr. James D. Shelton, Senior Medical Scientist, Office of Population, United States Agency for International Development (USAID).