Circumcision Could Lead To Better HIV Protection. Or Maybe Not.

Mass circumcision campaigns in sub-Saharan Africa have attempted to stem the tide of HIV infection by making men less infectious. Unsafe behaviors after circumcision, however, offset the benefits of circumcision.

In the United States, a majority of males are still circumcised (the foreskins of the penises surgically removed) at birth. Outside of the Muslim and Jewish worlds, however, male circumcision has always been a relative rarity, until scientists in the last decade learned that men who have been circumcised are less likely to spread HIV.

Circumcision Changes the Kinds of Bacteria That Live on the Penis

Probably the strongest predictor of whether a sexually active adult will be infected with the virus that causes AIDS is whether or not he or she already has been infected with the herpes virus. In studies of HIV transmission in India, researchers have found that men who are already infected with herpes are 2.5 to 14 times more likely to become infected with HIV when they are exposed to it, and women who are already infected with herpes are 1.4 to 2.8 times more likely to become infected with HIV when they are exposed the virus. But there are also factors that reduce the likelihood of exposure.

One of those factors is the presence of certain kinds of bacteria on the male penis. The penis is always inhabited by surface bacteria, but different kinds of bacteria predominate when the surface of the penis is exposed to the air, and when it is not. When a man has not been circumcised, most of the bacteria at the tip of his penis (the region known in science as the “coronal sulcus”) are anaerobic, that is, bacteria that do not depend on the air as their source of oxygen. When a man has been circumcised, most of the bacteria at the tip of his penis are aerobic, or oxygen-loving.

The Immune System Responds Differently in Circumcised and Uncircumcised Men

The immune system responds to anaerobic and aerobic bacteria in different ways. Generally, aerobic, air-loving bacteria are less threatening to the immune system, so the white blood cells in the skin of the penis are not as highly activated as they are in the presence of anaerobic bacteria. When white blood cells are not as active, they are less likely to bind to HIV, and there is less surface area on the penis that in which the immune system can become activated.  Consequently a man who has been circumcised is less likely to be infected by HIV and then less likely to spread HIV to his sex partners. Men who are circumcised are far less likely to acquire HIV infections during unprotected sex.

Circumcision does not appreciably change the risk of becoming infected by or infecting one's partner with gonorrhea, syphilis, or the Trichomonas microbe that causes severe urinary tract infections. Among sexually transmitted diseases, it just reduces the risk of HIV, although it reduces the risk of HIV transmission by 50% to 60%. But in countries where mass circumcision campaigns have been attempted to reduce the risk of spreading HIV, HIV rates have not necessarily gone down. The reason has to do with behavior.

Circumcision Doesn't Replace The Need for Condoms

In the early 2000's, the World Health Organization sponsored clinical trials of male circumcision as a means of reducing HIV transmission in Kenya, South Africa, and Uganda. All three trials showed positive results, and as a result, mass circumcision campaigns were initiated by other African nations that have extremely high rates of HIV infection, such as Zambia. The Zambian Ministry of Health developed its mass circumcision plan with a goal of having 80% of sexually active men in the nation circumcised by 2015.

After Circumcision as Adults, Some Men Become Sexually Adventurous

What the planners did not count on was the fact that getting a circumcision would lead some men to become sexually more adventurous.

In Kenya, researchers learned that HIV-positive men who did not have obvious symptoms of AIDS became slightly more likely to spread the virus in the month after the procedure.

HIV-positive men tended to have sexual intercourse just as soon as was physically possible after their circumcisions, in just three or four weeks, rather than waiting six to eight weeks for the cut to heal. Men who had never had sex before getting circumcised, as is the case in most Muslim populations, were considerably less likely to have sex before their wounds healed.

Prostitutes Especially at Risk

The women most at risk for HIV infection by recently circumcised men are prostitutes. As one Kenyan woman sex worker told a researcher from the Population Council, paraphrasing:

“This man comes in and tells me he only wants to have sex for a short time, and he is willing to pay 500,000 kenyatta (about US $600 /€475 /£400). I look at his erect penis and it's almost rotten. When it gets hard, out comes blood and pus, but I need the money, so I do the sex without a condom.”

Researchers found that most prostitutes even assumed that men who asked for sex without a condom are already infected, on the supposition that no man who was HIV-free would risk having sex with a prostitute without wearing a condom. Nearly all the women survived by one Population Council worker said they did not use condoms with their non-paying sex partners, and most erroneously believed that “going home to take some antibiotics” could prevent HIV infection.

Especially dangerous are recently circumcised men who practice “rough trade” with their sex partners, such as wearing metal studs on the penis during intercourse, although there are no data on just how many men engage in sadistic practices in sex.

Circumcision Makes Sex Safer, Not "Safe"

Circumcision undoubtedly makes sex safer, but not completely safe, in committed relationships. In casual relationships, however, male circumcision reduces the risk of getting or giving someone HIV, but does not replace the need for condoms.