Getting circumcision science right in the media
Published: July 9, 2012, 6 a.m., Last updated: Aug. 12, 2012, 12:07 p.m.
The evidence that voluntary medical male circumcision reduces the risk of a heterosexual man contracting HIV in high prevalence areas is beyond reasonable doubt.
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.
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:
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:
THE USAID STUDY
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 . 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."
THE SA NATIONAL COMMUNICATION SURVEY
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.
SAMA'S POSITION ON CIRCUMCISION
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."
TRANSMISSION FROM HIV-POSITIVE CIRCUMCISED MEN TO HIV-NEGATIVE WOMEN
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)
Hugh7 wrote on 10 July 2012 at 1:05 p.m.:
Hugh7 wrote on 11 July 2012 at 3:39 a.m.: