Study shock: Circumcised men have more HIV! Why?
Mpumalanga sample group goes against all previous studies and has researchers scratching their heads
Circumcision is a proven intervention that reduces the chance of catching HIV by 60%, but to scientists’ surprise, a study found that medically circumcised older men in Mpumalanga had a higher rate of HIV than uncircumcised men.The study was conducted by Indiana University Professor Molly Rosenberg and Professor Till Barnighausen from the Harvard T.H. Chan School of Public Health together with professors Kathleen Kahn and Stephen Tollman from the Wits Rural Health in Transition and Agincourt Research Unit.They surveyed about 2,345 Mpumalanga men aged 40 and older.
Rosenberg and Barnighausen said it is important to note that circumcision still works to reduce HIV risk, with more than 27 studies showing this.Three independently conducted randomised controlled studies previously showed circumcision reduced the risk of HIV by 60%.
Two had to be stopped early as circumcision worked so well to reduce change of catching HIV, it became unethical not to offer circumcision to the men who weren’t getting it in the trials.But in this latest study, published in PLOS One, the result was the opposite to what was expected by researchers.Men who reported being circumcised in hospital through voluntary medical male circumcision when older had a HIV prevalence rate of 31%, meaning almost one in three men were positive.
There are three theories why this study had such a counter-intuitive finding, Rosenberg and Barnighausen explained.
Their three theories are:
That HIV-positive men are opting for circumcision at higher rates, perhaps because they may be already going to clinics and getting antiretrovirals, so they use other services at the clinic.
The second theory is that men who are at higher risk of contracting HIV because they have many sexual partners or don’t like using condoms, opt for circumcision because they think it is a safe solution. However, because circumcision does not offer 100% protection from the disease, they still get HIV from unprotected sex.
That men engage in riskier sexual behaviour after circumcision because they know they are at decreased risk.
The researchers said they think the latter is probably the least likely explanation of the three because there have been multiple studies showing no evidence for this kind of risk compensation after medical male circumcision.
The theories have different consequences.The deputy director of the Wits Reproductive Health and HIV Institute, Professor Francois Venter, said if men were being more sexually risky after circumcision, communication about it needed to change.
“This well-conducted study should make us carefully look at our messaging around circumcision, so that we don’t lose some of the impact of this effective intervention.”
The other theory is that HIV-positive men are more likely to get circumcised.
The study report says government policy that HIV-negative men must get circumcised and awareness about its protective effects “gives the false impression that circumcised men are safer sex partners”.
The study also found that uncircumcised men aged 40 years and older in Mpumalanga showed an HIV prevalence rate of 24%, meaning one in four men above 40 was HIV-positive. Those circumcised through initiation while they were young had a prevalence of 16%, showing that getting circumcised younger really does reduce risk of HIV.
The study reads: “If HIV-positive men actually take up the circumcision procedure at high rates ... [and are seen by women as safer], it may have the unintended consequence of increasing HIV transmission.”
But researchers can’t say for sure why medically circumcised men in Mpumalanga have the highest rate of HIV.
Rosenberg said: “With the survey data we collected for this study, we unfortunately do not have the ability to tease out the different likelihoods of each of these explanations.”Asked if men could be lying about being circumcised as some cultures perceive this to mean the men are still “boys”, researchers didn’t think so.
Rosenberg wrote: “In our study population of over 2,000 men, only a quarter reported being circumcised, which is actually lower than the national estimate of circumcision rates. So any social desirability bias potentially distorting our findings is unlikely to be very large.”
Rosenberg said she did not believe the study would weaken plans to circumcise another two million South African boys and men by 2020.
“Current policies that promote circumcision as a tool to prevent HIV are not wrong. We strongly support universal circumcision of all men in South Africa, because it is known with certainty that circumcision biologically protects against HIV – based on three large well-conducted randomised controlled trials.”
Venter said: “South Africa has been relatively successful at rolling out medical male circumcision, and it probably is contributing to the 44% drop in new HIV infections in the last five years as reported by the Human Sciences Research Council a few weeks ago.”
The study was published in PLOS One journal on August 1...