Friday, July 31, 2009
Circumcision Doesn’t Reduce Male-to-Female Transmission of HIV
In recent years, the male foreskin—a double-folded tube of skin and mucous membrane that covers the head of the penis—has taken center stage in the battle against HIV. The foreskin is rich in Langerhans cells, immune cells that are particularly easy for the virus to access. Following infection, these cells not only serve as reservoirs for replicating the virus, but also transport it to nearby lymph nodes where HIV spreads to other immune cells. Studies have shown that removal of the foreskin can reduce a man’s risk of heterosexually acquired HIV infection by 50 to 65 percent, findings that prompted large-scale circumcision campaigns in countries with high infection rates, such as sub-Saharan Africa, where heterosexual sex is primarily responsible for the HIV epidemic. Studies had also suggested that circumcision could reduce the rate of male-to-female transmission of the virus, but that turns out not to be the case.
A Ugandan study, led by Dr. Maria J. Wawer of Johns Hopkins Bloomberg School of Public Health in Baltimore, was stopped early after it became apparent that male circumcision offered no protection to female partners. The study involved 922 uncircumcised, HIV-infected men between 15 and 49 years of age who were randomly chosen to either be circumcised or remain uncircumcised. The HIV-free female partners of the male participants were also enrolled in the study, 90 in the circumcised group and 70 in the uncircumcised group, and their HIV status was evaluated after 6, 12 and 24 months. All participants were intensively schooled in HIV prevention and provided free condoms.