Circumcision lowers bacterial load, possibly allowing for HIV infection risk reduction, researchers say

"Circumcision reduces a man's risk of acquiring and transmitting HIV and other sexually transmitted diseases, and now researchers have found a possible explanation: the procedure reduces the quantity and diversity of bacteria at the head of the penis," the New York Times' "Well" blog reports (Bakalar, 4/18). In a study published this week in mBio, "researchers studied the effects of adult male circumcision on the types of bacteria that live under the foreskin before and after circumcision," and they found that one year post-circumcision, "the total bacterial load in that area had dropped significantly and the prevalence of anaerobic bacteria, which thrive in locations with limited oxygen, declined while the numbers of some aerobic bacteria increased slightly," according to a press release from the American Society for Microbiology (4/16). "By reducing the number of anaerobic bacteria, the body's immune cells may be better able to destroy the virus -- and less likely to fall prey to its Trojan horse-style of attack, the authors suggest," the Los Angeles Times writes. The newspaper notes, "Further research must be done to draw a direct connection between these changes in the microbiome and subsequent HIV infection" (Morin, 4/15).

http://www.kaiserhealthnews.orgThis article was reprinted from with permission from the Henry J. Kaiser Family Foundation. Kaiser Health News, an editorially independent news service, is a program of the Kaiser Family Foundation, a nonpartisan health care policy research organization unaffiliated with Kaiser Permanente.



  1. Mark Lyndon Mark Lyndon United Kingdom says:

    Female genitals are harder to clean than men's, but we don't cut parts off baby girls to make it easier.

    It's illegal to cut off a girl's prepuce, or to make any incision on a girl's genitals, even if no tissue is removed. Even a pinprick is banned. Why don't boys get the same protection? Everyone should be able to decide for themselves whether or not they want parts of their genitals cut off. It's *their* body.

    Male circumcision doesn't seem to help against AIDS either.  From a USAID report:
    "There appears no clear pattern of association between male circumcision and HIV prevalence—in 8 of 18 countries with data, HIV prevalence is lower among circumcised men, while in the remaining 10 countries it is higher."

    It's really easy to find circumcised doctors who are against circumcision, but surprisingly difficult to find male doctors in favor who weren't circumcised themselves as children.

  2. Hugh Intactive Hugh Intactive New Zealand says:

    This study merits a great big "SO WHAT?" It's hardly surprising if an enclosed part of the body, like between the toes, has different bacteria from an open part. The rest of the study is pure speculation piled on more speculation. But just let a story say "circumcision" and "HIV" and the media are all over it.

    When are the media going to notice that it is just a tiny clique of interconnected researchers who are doing nothing but churning out articles in support of infant circumcision? In this case, the clique members are Aaron Tobian, Maria Wawer, Ronald Gray, David Serwadda and Godfrey Kigozi. Their study is of two groups of only 78 paid adult volunteers for circumcision - hardly a large or random sample of the population; each man accounts for 1.2 percentage points. They were recruited by inviting each other, so they would tend to know each other and maybe even have sexual partners in common. They are part of one of the three studies claiming to show that circumcision reduces HIV transmission (but only from women to men), that circumcision is safe, that it does no harm to sex and (not so publicised) that it does not reduce HIV transmission from men to women. (In fact they found it may INCREASE it, but that has had zero publicity.) They must be one of the most over-used experimental groups in history.

    Why did they not give equivalent publicity to the letter from 38 top paediatricians - heads or spokespeople for 22 paediatric associations in 17 countries - basically the whole of Europe - pointing out that the American Academy of Pediatrics circumcision policy is culturally biased, utterly fails to show that the benefits outweigh the risks, and fails to assign any weight to the individual's right to choose the fate of his own genitals? (  They wrote because the AAP policy was being touted to promote legalising infant circumcision in Germany, contrary to its constitution.)
    Or a new study showing that circumcision has no significant effect on STI transmission? (

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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