Source: WebMD, AFP, Time, Reuters
There is not enough evidence to say circumcision protects men from getting the AIDS virus during sex with other men, a new study concludes, but it might cut HIV risk in predominantly insertive partners,
Circumcision has been found to reduce by about one-half the transmission of HIV between heterosexuals, but it appears to offer far less protection for men who have sex with men, according to the study.
The research published in the October 8 issue of The Journal of the American Medical Association compiled 15 discrete studies of more than 50,000 male subjects in Africa.
It is the most comprehensive analysis of the subject to date. It encompasses data from 15 studies conducted in seven countries, involving more than 53,000 men, most of whom were Caucasian and approximately half of whom were circumcised, Time reports.
The report by the US Centers for Disease Control and Prevention noted that male circumcision appears to reduce by between 50 and 60 percent the likelihood of female-to-male transmission of the HIV virus, AFP reports.
But the data showed a generally weak effect among gay/bisexual men: a 14% lower risk of HIV infection. Researchers said the finding was not statistically significant, which means even this small benefit could very well be due to chance.
A team of peer reviewers from Vanderbilt University concluded in the a Journal editorial that "circumcision would likely be insufficiently efficient to be universally effective in reducing HIV risk, and will have to be combined with other prevention modalities to have a substantial and sustained prevention effect."
However, the study found two areas where circumcision may be advantageous even for men who have sex with men: Circumcision may reduce risk of infection for tops or -- in the words of the study -- "predominantly insertive partners" and may also be more effective if men usually engage in safe sexual practices.
In the few studies that looked specifically at men who mainly engaged in insertive anal sex, circumcision seemed to offer more protection, WebMD reports. This effect was much stronger in populations where relatively few men are circumcised.
The review suggested that among insertive partners, circumcision lowered HIV infection risk by 29%, a finding that also showed statistical nonsignificance. But targeting that distinct population in future studies may prove useful for distilling the specific effect of circumcision — and perhaps for future public-health strategies.
It's a very important issue, says Sten Vermund, MD, PhD, director of Vanderbilt University's Institute for Global Health.
"The prospect that predominantly insertive men might derive considerably more benefit from circumcision is as logical as the day is long," Vermund tells WebMD. "What benefit is a predominantly receptive man going to gain from circumcision?"
Vermund notes that there is good evidence that, in many parts of the world, a high proportion of men who have sex with men are exclusively or predominantly insertive sexual partners. In areas where few men now are circumcised, circumcision could have a powerful effect on HIV transmission -- if it went hand-in-hand with safer sexual behavior.
"To add one more tool to our HIV prevention toolbox -- even if it affects only 40% of a risk group -- would be substantial," Vermund said.
"For every insertive man who is protected, there might be a receptive man who isn't infected, for the same reason why women get protected ... in other words, from a herd-immunity phenomenon," he said.
Vermund noted that a clinical trial to test this approach is needed. Whether such a study can attract increasingly scarce funding is an open question
"This study gives us a more complete picture than we've ever had before," says Gregorio Millett, the study's lead author and a senior behavioral scientist at the Centers for Disease Control and Prevention (CDC). "The next step is to design better quality studies to see if there is an association we aren't detecting."
Historical analysis of data also suggests another significant finding according to WebMD.
Because studies done before the 1997 advent of highly effective HIV drugs showed that circumcision cut men's risk of getting HIV by 53%, the new figures may reflect high risk from unsafe sex according to Millett.
The widespread belief that anti-retroviral drugs could prevent HIV transmission led to an increase in risky sexual behavior, outbreaks of sexually transmitted infections and increasing rates of HIV, which, the study's authors say, may have diminished the relative effectiveness of male circumcision, Time reports.
"There has been an increase in sexual risk behavior in men who have sex with men since the availability of highly effective treatment for HIV," Millett tells WebMD. "If a man is engaged in unprotected sex or has lots of sex partners, that contributes more to his risk of HIV than being uncircumcised. So in recent years, the benefit of circumcision may have been overridden by the risks of unsafe sex."
Circumcision is believed to lower HIV transmission in several ways, Time reports. The inner surface of the foreskin is rich with cells that are more vulnerable to HIV than cells on other parts of the penis. Because they are also closer to the skin surface and at higher risk for tears during intercourse, they increase susceptibility to infection.
Removal of the foreskin further lowers men's odds of developing genital ulcers (from diseases such as syphilis), which in turn lowers their vulnerability to HIV during intercourse. In theory, circumcision should be protective for all men who participate in insertive sex, including heterosexual men and men who have sex with men.
But researchers note that circumcision is no cure, and no substitute for safe-sex measures such as using condoms.
Source: Can Circumcision Cut HIV in Gay Men? | WebMD
Little HIV protection from circumcision for gay sex: study | AFP
New Debate Over Circumcision, HIV Reduction | Time
No proof circumcision cuts gay male HIV risk-study | Reuters