Medical male circumcision: is the HIV prevention claim wrong?
A study has found that medically circumcised older men in Mpumalanga have a higher rate of HIV than uncircumcised men
Circumcision is a proven intervention that reduces the chance of contracting HIV by 60%, but to scientists’ surprise, a study has found that medically circumcised older men in Mpumalanga had a higher rate of HIV than uncircumcised men.
The findings appear to suggest that it needs to be communicated to both men and women that circumcision does not offer 100% protection against HIV.
The study, published in the PLOS ONE journal on August 1, was conducted by Indiana University professors Molly Rosenberg and Till Barnighausen from the Harvard TH Chan School of Public Health, together with professors Kathleen Kahn and Stephen Tollman from the Wits Rural Health in Transition and Agincourt Research Unit.
The researchers surveyed about 2,345 Mpumalanga men, who were 40 years and older.
Men who reported being circumcised in hospital through voluntary medical male circumcision when older had an HIV prevalence rate of 31%, meaning that almost one in three men were positive.
Rosenberg and Barnighausen say it is important to note that circumcision still works to reduce the risk of contracting HIV, with more than 27 studies showing this.
Three independently conducted randomised controlled studies previously showed circumcision reduces the risk of HIV by 60%. Two had to be stopped early as circumcision worked so well to reduce the chance of catching HIV, it became unethical not to offer circumcision to the men who were not getting it in the trials.
However, in this latest study, 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 an HIV prevalence rate of 31%, meaning that almost one in three men were positive.
There are three possible theories for the counterintuitive finding, Rosenberg and Barnighausen explained.
The first of their three theories is that HIV positive men are opting for circumcision at higher rates.
This may be because they may already be going to clinics and getting antiretrovirals, and then make use of other services available at the clinic.
The second theory is that men who are at higher risk of contracting HIV because they have many sexual partners or do not like using condoms, opt for circumcision because they think it is a safe solution.
However, they then still get HIV from unprotected sex.
It could also be, still in accordance with the second theory, that men engage in riskier sexual behaviour after circumcision because they know they are at decreased risk.
However, the researchers say the second theory is probably the least likely explanation because multiple studies have showed no evidence for this kind of risk compensation after medical male circumcision.
Prof Francois Venter, deputy director of the Wits Reproductive Health and HIV Institute, said if men are taking greater sexual risks after circumcision, communication about it needs 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 third theory is that HIV-positive men are more likely to get circumcised. The study 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 says: "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."
The study also found that uncircumcised men 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 the risk 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."
That men could be lying about being circumcised as some cultures perceive this to mean they are still "boys", was rejected by the researchers.
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.
"We strongly support universal circumcision of all HIV-men in SA, because it is known with certainty that circumcision biologically protects against HIV — based on three large well-conducted randomised controlled trials."
Venter said: "SA 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 [has been] reported by the Human Sciences Research Council a few weeks ago."