Getting circumcision science right in the media

The evidence that voluntary medical male circumcision reduces the risk of a heterosexual man contracting HIV in high prevalence areas is beyond reasonable doubt.

The Steadfast Philosopher by Andries Both. Source Wikigallery.

In June, Philosopher Brian Earp wrote an article titled A fatal irony: Why the “circumcision solution” to the AIDS epidemic in Africa will increase transmission of HIV.

In an article on circumcision last week, Daily Maverick journalist Jacques Rousseau wrote: "Though it’s repeated so frequently as to seem axiomatic, the evidence that circumcision reduces HIV infection is not as clear-cut as many think it is."

They are both wrong. The evidence that circumcision reduces the risk of HIV transmission for heterosexual men in high prevalence areas is about as clear-cut as you'll find in medical science.

Three well conducted randomised controlled trials, in South Africa, Kenya and Uganda showed that circumcision was highly effective. The findings of these trials are supported by quality observational studies. There is also a plausible biological explanation for the mechanism by which circumcision works.

Earp's article is especially poorly researched. Besides making discredited stale arguments against the three clinical trials, he puts forward the much touted but evidence-free view that circumcised men will be at greater risk of HIV infection because they will take more risks due to the false belief that circumcision protects them.

Risk compensation has been studied. There is no sign that it is reversing the considerable benefit of circumcision. See here and here.

In 2008, a group of us published a clearly written peer-reviewed article in Future HIV Therapy that comprehensively debunks the arguments purporting to show that circumcision does not protect heterosexual men against HIV infection:

Male circumcision is an efficacious, lasting and cost-effective strategy for combating HIV in high-prevalence AIDS epidemics

The World Health Organisation recommends circumcision to reduce the risk of HIV infection. So do many other reputable institutions. I am not aware of any reputable medical body that recommends against it for areas with large primarily heterosexual HIV epidemics.

There are complex ethical questions about infant circumcision. There are difficult operational and political problems to be overcome to properly implement circumcision in South Africa. The Kwa-Zulu Natal government is rolling out circumcision irresponsibly, particularly --but not only-- because it is using an unsafe circumcision device called the Tara KLamp. Traditional --as opposed to medical-- circumcisions in the Eastern Cape are a disaster, with 20 initiates reportedly dying this year. That the state continues to fail to prevent this annual tragedy is shameful.

Nevertheless the science is clear: medical circumcision of adult males reduces their risk of acquiring HIV from HIV-positive women.

Additional points added on 10 July

The debate that has followed the publication of the above article has once more shown that people ideologically opposed to circumcision insist on citing selectively and ignoring the peer-reviewed studies that have shown the HIV prevention benefits of circumcision. Because the science does not support their preconceived notions, they insist on misrepresenting the science. One of the comments posted below this article by Mark Lyndon exemplifies this.

I have no problem with someone saying, "I have no desire to be circumcised. My foreskin is important to me."

But it is deeply problematic to claim that the scientific evidence indicates that this is the healthier choice in large heterosexually driven HIV epidemic areas. I accept too that there are reasonable ethical arguments against infant medical circumcision with parental consent, albeit that I lean towards believing it to be ok.

Below are responses to Lyndon's misrepresentations:


Lyndon cites a USAID study which found no difference in HIV prevalence between circumcised and uncircumcised men across eight countries.

The USAID study contains a subsection that looks at the correlation between circumcision and HIV in a very unsophisticated way. The Future HIV Therapy article I cited, which is the definitive debunking of the anti-circumcision arguments deals with the complexity of observational studies and what they have shown:

"a systematic review and meta-analysis of 27 observational studies found strong and consistent evidence that circumcised men were at significantly reduced risk of HIV, and in 15 studies that adjusted for potentially confounding factors, the association was even stronger [15]. This result is consistent with numerous other observational studies [13,16,17,21,102,103]. It is important to note that, since MC status is often associated with particular patterns of behavior, results from observational studies should be adjusted for potential confounding factors."



Lyndon cites a survey that found that 15% of men believed a condom was unnecessary if you were circumcised.

While the findings are worrying, the real measure of the effects of risk compensation behaviour has to come from study sites where circumcision has been implemented, not opinion surveys. In this regard, there is no evidence that risk compensation has had an effect. On the contrary the prevention effect of circumcision is sustained long after the clinical trial periods in the South African and Kenyan sites.






Lyndon cites a document that purports to show that the South African Medical Association opposes circumcision.

The continued misrepresentation by anti-circumcision advocates of SAMA's position on circumcision is at best sloppy, but quite possibly just dishonest.

SAMA responded to NoCirc's misrepresentation, repeated by Lydon above:

"Our previous correspondence, dated 5th July 2011, refers. This letter clearly clarified our position following an unintentional error in our initial correspondence, dated 23 June 2011. Unfortunately it would seem that you decided to misrepresent our stated position on the above matter in recent communication to the Department of Health and on your website. The correspondence you refer to was incorrect and has been withdrawn and superseded by our consequent letter. Our position is simple and clear – automatic circumcision of infant males IN THE ABSENCE OF PARENTAL CONSENT is not appropriate. Adult male circumcision is an accepted HIV prevention strategy. Kindly read our second letter and desist from using incorrect correspondence to portray our position in addition to doing this on your website."



Lyndon claims a Lancet study found a 51% higher risk of HIV transmission from HIV-positive circumcised men to HIV-negative women.

It is true that there is no prevention benefit to HIV-positive men getting circumcised. The WHO recommendation is directed at HIV-negative men. A study is currently underway in Orange Farm to assess the effect of community-wide circumcision of men on HIV transmission to women, though modelling studies indicate that there will be reduced transmission to women (and there is also likely to be reduced transmission of HPV to women, the virus that causes cervical cancer).

Nevertheless, Lydon misrepresents or fails to understand the Lancet study he cites. For stats geeks, the study tells us that the adjusted hazard ratio was 1.49, but it also explains that the 95% confidence interval is 0.62-3.57 and that the p-value equals 0.368. What this means in plain English is that the difference between the circumcision and non-circumision arms was not significant. It cannot be attributed to anything but chance.

I plead with circumcision sceptics who are genuinely interested in understanding the science to read the Future HIV Therapy article.

There are two further anti-circumcision arguments I wish to address:

Fallacy: The circumcision trials were not blinded and there were no placebo arms, so they are not quality trials. This is an argument made by Earp (citing Boyle - both articles are linked to above in my original article).

It's impossible for many kinds of clinical trials, either for practical or ethical reasons, to have a placebo arm. It's clearly impossible to administer a placebo circumcision! While double-blinded placebo controlled clinical trials are the gold standard, it doesn't mean that trials that do not have placebos are inadequate. Some of the most important trials that I'm familiar with from recent years have no placebo. For example the SMART trial, to determine whether antiretroviral treatment could be safely interrupted. Another seminal antiretroviral trial without placebo was the CHER study which showed that immediate treatment of children reduced deaths over deferred treatment. If Earp refuses to accept the results of three randomised controlled circumcision trials because they were open-label and did not have a placebo arm, then he must refuse also to accept the results of SMART, CHER and many, many other fine clinical trials.

False: The fact that participants in the circumcised arms of the trials were counselled not to have sex during the wound-healing period (about 6 weeks), can account for the superior results of the circumcision arms over the control arms. (Also made by Earp, citing Boyle.)

This is an example of Boyle and Earp simply expressing their prejudices in print without first checking them against the facts. For their assertion to be true, most of the difference in the circumcision and control arms would have to have occurred in the first 3 months (which includes the wound healing period of about 6 weeks). But in the Kenyan trial, there was no difference in infections between the arms at three months (if anything, it's slightly but insignificantly in favour of the control arm at that point). In the Orange Farm trial the benefit at three months to the circumcision arm is tiny.

Comments in chronological order (14 comments)

Kevin wrote on 9 July 2012 at 7:47 a.m.:

Thanks for posting this Nathan, the details of those studies do need a wider audience.

I think it should be added that the WHO recommendation is a qualified one: MC is recommended in areas of high HIV incidence and low prevalence of MC. They also make it clear it is not a primary protection. The WHO page on circumcision

Is there any kind of follow up being done with the participants of these studies? Although the original studies were closed early because of the clear benefit - it would be interesting to know the long-term effectiveness.

Nathan Geffen wrote on 9 July 2012 at 8:56 a.m.:

Good points Kevin.

The WHO states:

WHO/UNAIDS recommendations emphasize that male circumcision should be considered an efficacious intervention for HIV prevention in countries and regions with heterosexual epidemics, high HIV and low male circumcision prevalence.

This seems spot-on to me.

Follow-up studies have been done and continue to be done. See for example these two reviews I wrote for i-Base of follow-up Kenyan and Orange Farm studies:

Brian wrote on 9 July 2012 at 9:55 a.m.:

This is exactly right. Excellent response from Nathan to this madness. The WHO recommendations could not be clearer. I guess some people will never give up and are not amenable to reasoned argument.

Foo wrote on 9 July 2012 at 10:46 a.m.:

How about wearing a condom instead of removing part of the penis?

If removing part of the penis is partly effective, removing the whole penis would be totally effective - and I don't see anyone recommending that as an effective intervention to prevent HIV transmission.

Debbie wrote on 9 July 2012 at 4:17 p.m.:

I think the circumcision of boys and adult men is a very important part of the prevention of HIV, Much more must be done to upscale it. We need more resources, doctors nurses and clinics for this purpose. If countries could send men to their death in wars, way can surely send men to Hospital for medical circumcision for their own, their partner and the countries health. HIV is the toughest war we are fighting now, where is our brave soldiers now? Besides most women like circumcised men and male circumcision have many added benefits as well. All these scientist and doctors cannot be wrong. Parents should take action and have their sons circumcised, wives and girl friends must pressure adult men to have it done. Schools should encourage it and more religions and organisations should mandate it for their members. This is not MC vs FGM, it is about saving lives and preventing HIV.

So common boys, don’t be shy. The knife is waiting and your country is calling upon you to be brave and do the right thing. Like it or not, South Africa and other countries have an 80% circumcision target to hit by 2015 for men between 15-45 so get on with it.

Lyle wrote on 9 July 2012 at 5:09 p.m.:

Why is this not seen for what it is? Imperialistic westerners imposing their will on susceptible Africans. 20 years from now, there will be a backlash. Bodily integrity is everyone's basic human right. Obviously it would make just as much sense to trim up baby girls' genitalia as there is much more room for those nasty germs to hide. But girls are protected and boys aren't.

All the 'science' in the world does not compensate for the massive loss in sensitivity and the forced taking of parts of a boy's body.

Mark Lyndon wrote on 9 July 2012 at 10:02 p.m.:

Real world data suggests that male circumcision has little or no effect on HIV rates.

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."

The South African National Communication Survey on HIV/AIDS, 2009 found that 15% of adults across age groups "believe that circumcised men do not need to use condoms".

From the committee of the South African Medical Association Human Rights, Law & Ethics Committee : "the Committee expressed serious concern that not enough scientifically-based evidence was available to confirm that circumcisions prevented HIV contraction and that the public at large was influenced by incorrect and misrepresented information. The Committee reiterated its view that it did not support circumcision to prevent HIV transmission."

The one randomized controlled trial into male-to-female transmission showed a 54% higher rate in the group where the men had been circumcised btw:

ABC (Abstinence, Being faithful, and especially Condoms) is the way forward. Promoting genital surgery seems likely to cost African lives rather than save them.

Marcus wrote on 10 July 2012 at 11:51 a.m.:

Dear Mark Lyndon

You are cherry-picking evidence to suit your views. It would be much more honest to express a moral objection than to pretend your objection is based on science.

If you look at the totality of the evidence the benefit from circumcision is indisputable. How much more evidence could you possibly want than the three large RCTs plus the observational data. If you have an honest interest in this issue, i suggest you click on the link in the above article "Male circumcision is an efficacious, lasting and cost-effective strategy for combating HIV in high-prevalence AIDS epidemics".

Regards Marcus

Kevin wrote on 10 July 2012 at 12:55 p.m.:

Thanks Marcus. I'm not sure that either of Debbie's (cut all) or Mark's (cut none) views are correct. The WHO recommendation is far more nuanced. The evidence is strong and the recommendation clear - in high-HIV / low-MC areas.

I haven't seen any strong evidence in areas of relatively low HIV incidence (like Germany, which was the crux of Jacques' article around the moral issues).

As Nathan indicates - this is an ethically loaded issue. I think too many from the no-cut camp are influenced by European views where HIV is less prevalent; and too many of the cut-and-be-damned camp are pointing to these studies in support of discarding the ethical issues. I'm not convinced the evidence has reached the point where we can unequivocally say this must be done to children (unlike vaccines where moral, sexual and ethical issues play little or no role).

imho the answer (at present) for South Africa lies somewhere in between - consensual MC side-by-side with education and free access to prophylaxis.

What is encouraging from the additional links posted by Nathan in the comments is that there has been no negligible effect on condom usage, and no evidence of increasing risky behaviour by those circumcised. That takes most of the wind out of the Brian Earp camp.

Hugh7 wrote on 10 July 2012 at 1:05 p.m.:

"Beyond reasonable doubt"? You've got to be joking!

The three trials, two of them by previous circumcision advocates, on paid volunteers for circumcision, not (perforce) double-blinded or placebo controlled, the circumcised group ordered to abstain from sex for six weeks, all three studies cut short prematurely (a known factor in finding false positive outcomes), and with drop-out rates several times the infection rates, with no contact tracing and hence no assurance that the infections were (hetero)sexual - "well conducted"? Please!

Observational studies? In 10 out of 18 countries for which USAID has figures, more of the circumcised men have HIV than the non-circumcised.

Just in, seven years later and three years after a circumcision campaign began, one of those countries, Zimbabwe has almost the same result as before.

"Risk compensation has been studied. There is no sign that it is reversing the considerable benefit of circumcision." You should tell that to Zimbabwe's National Aids Council (Nac) public health officer Dr Blessing Mutede, who said authorities were concerned about the high rate of infection among the circumcised. He said it was largely a result of “risk compensation behaviours”.

If risk compensation explains the higher rate among the circumcised now, what explained it in 2005, when the ratio was the same but the circumcised men had been done so culturally, not as part of a campaign?

Plausible mechanism? When Langerhans cells are all over the body and the claim is based on a few foreskins of dead old men in petri dishes?

Abstenence, avoiding multiple concurrent partners, and condoms prevent HIV. Getting (the best) part of your genitals cut off, not so much.

Nathan Geffen wrote on 10 July 2012 at 1:18 p.m.:

I added a new section to the article on 10 July addressing the points raised above.

Hugh7 wrote on 11 July 2012 at 3:39 a.m.:

It is not quite true that there is no such thing as a placebo circumcision. Dummy operations are used as placebo in surgical studies. An "operation" that just opened the skin around the penis and closed it again would require the same counselling and healing, gain the same time for additional safe-sex advice, present the same risk and could be accurately described as a "circular incision". As well as the various placebo effects, it would provide some blinding, since many men do not know what a true circumcision should look like. Auvert says such a thing would not be ethical, but that is a bit rich coming from the author of a study that did not tell men when they were HIV+!

We might not pick on these aspects so much if circumcision advocates did not tout the three RCTs as the Gold Standard when they fall so far short of it. "Ideally" HIV- men would be taken from the street, circumcised willynilly (or randomonly not), locked up with HIV+ women and tested some time later - as we would do with rats. Some human medical experimentation is just not practicable because it is unethical, but we should not pretend that the next most accurate thing is just as good.

Your fine-tuning of the timing that the men got infected is somewhat beside the point when so few did - only 64 altogether out of 5,400 circumcised. Any effect of lead-time bias could be lost in the random noise. As well as Boyle's study of this, you should consider Gisselquist's.

The Wawer study on male-to-female transmission did not reach statistical significance because it was cut short "for futility" (it failed to show that circumising men protects women) and the victims were blamed for resuming sex too eaarly, when a longer study would have shown whether that really was the reason. (Ethically there was nothing to lose by carrying on since they had established that circumcising the countrol group would not protect their partners.) Clearly these people only want to find one thing.

Mark Lyndon wrote on 15 July 2012 at 5:20 p.m.:

  1. If male circumcision really conferred a 55-60% reduction in female-to-male infectivity, then how is it possible that 10 of 18 countries have higher rates of HIV in circumcised men? It's hard to see how confounding factors could account for more than two or three at most. Since those who circumcise for religious reasons typically have fewer sexual partners, you'd expect lower rates among circumcised men, even if circumcision had no effect. Either circumcised men are engaging in riskier sexual behavior (in which case it would make more sense to change the behavior of circumcised men rather than to circumcise intact men), or male-to-female infectivity is increased. Since male circumcision is only supposed to help those males who have unsafe sex with HIV+ partners, why should there be any diversion from ABC?

It's worth noting that an alleged observed lower risk of HIV in circumcised men was supposed to be the justification for the RCT's, yet more than half of the countries in the UNAID report had higher rates of HIV in circumcised men.

  1. I have to say I'm highly skeptical that real world results will reflect the findings of study sites anyway, but if 15% of South African adults "believe that circumcised men do not need to use condoms", then it's just not realistic to think that there will be no risk compensation. Remember that men who are already circumcised (medically or otherwise) will receive no extra education about safe sex, and they are already making decisions about who to have sex with and whether or not to use condoms. Even small reductions or increases in the rate of unsafe sex can have a large effect on seroconversions. Your second link doesn't seem to be working btw.

  2. I was unaware of SAMA's response, and will stop using that quote. However, it seems that there are differences of opinion between members of SAMA, as it seems unlikely that this statement was an "unintentional error": "the Committee expressed serious concern that not enough scientifically-based evidence was available to confirm that circumcisions prevented HIV contraction and that the public at large was influenced by incorrect and misrepresented information. The Committee reiterated its view that it did not support circumcision to prevent HIV transmission."

Mark Lyndon wrote on 15 July 2012 at 5:20 p.m.:

  1. The Wawer study did not show statistical significance (and I didn't actually say it did), but the fact remains that it is the only RCT into male-to-female transmission, and it did show a 54% higher rate among the circumcised men. Not finding a statistically significant difference does not mean that there is no difference. Given the numbers involved, there would actually have to have been more than double the rate of infection to show statistical significance. Crucially, there will never be a larger scale RCT to find out if circumcising men increases the risk to women. Somehow that's considered unethical, yet it's considered ethical to promote male circumcision whilst not knowing if the risk to women is increased (by 54%?, 0%?, 108%? - who knows?) Why was the Wawer study stopped early anyway? The men were already circumcised, so why did it not continue? The only reason I can think of is that it didn't give the reason they were looking for, and they were worried that if it continued, it may show a statistically significant increase later.

Male circumcision has been linked with HIV in women before btw. It's a long time ago, but a 1993 study found that "partner circumcision" was "strongly associated with HIV-1 infection [in women] even when simultaneously controlling for other covariates."

Why are HIV+ men being circumcised anyway? In Swaziland, about 19.5% of intact men already have HIV, so about one in five men undergoing VMMC already has HIV. There is no evidence that circumcising HIV+ men will help anyone, and there is evidence that it may make them more dangerous to their sexual partners. (the HIV rate among circumcised Swazi men is 21.8% btw , table 14.10)

Remember that every million dollars spent on surgery is money that could have been spent on condoms, education, ART or PMTCT or tackling other diseases (AIDS killed an estimated 2 million people worldwide in 2007, but an estimated 3.5 million children die each year from diarrheal diseases and pneumonia).

I'd support male circumcision (and even minor forms of female cutting) to prevent HIV if 1) I thought it worked, and 2) it was a cost effective approach

but to me, the evidence doesn't even come close.

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