Circumcision cuts HIV risk by 50% for heterosexual African American men

Circumcision reduced the risk of HIV infection by 50% for African-American men with a known sexual contact with an HIV-positive women, according to US research published in the January 1^st 2009 edition of the Journal of Infectious Diseases. The reduction in HIV risk for circumcised men is similar to that seen in three randomised, controlled trials looking at the efficacy of circumcision as a method of HIV prevention in Africa.

Male circumcision has been the focus of considerable attention as a method of HIV prevention in recent years. It has been demonstrated that the cells in the foreskin are vulnerable to HIV infection and that circumcision reduces the risk of HIV infection for men in sub-Saharan Africa.

There is little information on the efficacy of circumcision for heterosexual males as a method of HIV prevention in the US. This is partly because the US has a low HIV prevalence (0.4%) and also because the epidemic is concentrated in gay men and other men who have sex with men, in whom the protective effect of circumcision is less clear.

In order to evaluate the association between circumcision status and the risk of HIV infection in a population of African-American men attending sexual health clinics in Baltimore, investigators conducted a retrospective study of 40,571 clinic visits between 1993 and 2000. All the patients were tested for HIV and clinic notes recorded if the men were circumcised or uncircumcised, and if they had an ulcerative or urethral sexually transmitted infection.

The investigators were also able to identify a subset of 394 visits that were made because the men had been notified that they had been exposed to HIV after penile-vaginal contact with a woman with diagnosed HIV infection. This enabled the investigators to look at the efficacy of circumcision as a method of HIV prevention in men known to have had exposure to HIV.

Most of the men (87%) were circumcised. HIV prevalence was four times higher in the subset of 394 clinic visits made because of documented exposure to HIV than in the 40,177 visits by men with no certain exposure to HIV (12% vs 3%).

Among the 394 men who attended the clinic because of known HIV exposure, circumcision was associated with a significant 51% reduction in HIV prevalence (10% vs 22%).

However, among the 40,177 visits by men without documented HIV exposure, there was no difference in HIV prevalence between circumcised and uncircumcised men (both 3%). In this group, however, HIV prevalence was higher amongst men who had an ulcerative sexually transmitted infection (7%) than those with a urethral infection (2%).

“The around 50% reduction in prevalence observed among men with known HIV exposure is of comparable magnitude to the risk reported across the three African trials (range, 48% to 60%),” comment the investigators.

They conclude, “circumcision was associated with significantly reduced HIV prevalence among a cohort of African-American heterosexual men with known HIV exposure who were attending Baltimore sexual [health] clinics…these findings may also demonstrate that the benefits of circumcision may be most evident in observational studies of male patient populations with documented exposure to HIV-infected female partners.”

The authors of an accompanying editorial note that, although the American Academy of Pediatricians recognises “potential medical benefits of newborn male circumcision”, it believes “data are not sufficient to recommend routine neonatal circumcision.” The authors write that circumcision rates are falling in the US and are low amongst African-Americans and Hispanics, groups with increased HIV prevalence. They express the hope that the findings will persuade the American Academy of Pediatricians “to recognize the public health importance of this surgery for the prevention of HIV infection in minority US populations.”