Originally posted on January 14. 2012
For several years, many organizations have argued that the best way to reduce HIV infections in Africa is to circumcise men and boys. These groups cite three randomized clinical trials (RCTs) as conclusive proof that circumcision prevents HIV. Since then, several governments have pushed for male circumcision. However, a recent paper challenges that effort.
Robert S. Van Howe and Michelle R. Storms dissected the results of the RCTs. They argue that the trials all shared the same “expectation bias (both researcher and participant), selection bias, lead-time bias, attrition bias, duration bias, and early termination that favored the treatment effect the investigators were hoping for.” These biases resulted in the assumption that all HIV infections come from heterosexual sex, and so none of the researchers bothered to actually check where the infections came from. The researchers may have potentially overstated the number of HIV infections from heterosexual sex:
In the South African trial, men who reported at least one episode of unprotected sex accounted for 2498 person-years and 46 HIV infections during the trial. Among the remaining men, who accounted for 2076 person-years, 23 become infected although they either had no sexual contact or always used a condom. These men, who had infection rate of 1.11/100 person-years (95%CI=0.74-1.67), presumably became infected through non-sexual means. The men at sexual risk of infection had an infection rate of 1.84/100 person-years (95%CI=1.38-2.46). It would be expected that all men in the trial shared the same baseline risk of non-sexual transmission and any additional risk could be attributed to sexual transmission. The infections attributed to sexual contact would be the difference between the total rate and the non-sexually transmitted rate (0.73/100 person-years). Consequently, only 18 (0.0073 infections per person-year * 2498 person-years) of the 69 infections in the South African trial can be attributed to sexual transmission.
In Ugandan trial, men who consistently used condoms had the same rate of infection as those who did not. If, as the RCTs researchers argued, the greatest risk comes from sexual transmission, this should not happen.
Van Howe and Storm moved on to the idea that the foreskin makes men more susceptible to HIV infections:
Proponents of the circumcision solution have speculated that the interior mucosa of the prepuce is thinner and more prone to tearing, but mucosa of the inner and outer prepuce have been shown to be of the same thickness. Proponents also speculate that HIV is more likely to be transmitted through the foreskin because it has a high concentration of Langerhans cells, which they believe are the entry point for HIV. Research has shown that Langerhans cells are quite efficient in repelling HIV and explains why the transmission rate of HIV is one per 1000 unprotected coital acts. The inner foreskin secretes langerin, which kills viruses. Langerhans cells also protect against other sexually transmitted infections (STIs), which may explain why circumcised men are at greater risk for getting an STI (unpublished data).
Simply put, there is no direct evidence showing that having foreskin puts men at greater risk, and there is anecdotal data to supporting that conclusion. The United States has a large population of circumcised men, yet the country also has a high-rate of heterosexual HIV transmissions, particularly among black men, who are one of the largest groups of circumcised men. If circumcision prevented HIV infections, one would expect to see a lower rate of infections among circumcised men, yet we do not. The same evidence exists in Africa countries:
In Africa, there are several countries where circumcised men are more likely to be HIV infected than intact men, including Malawi, Rwanda, Cameroon, Ghana, Zimbabwe, Lesotho, Swaziland, and Tanzania. Even in South Africa, where one RCT was undertaken, 12.3% of circumcised men were HIV-positive, while 12.0% of intact men were HIV-positive. If the national survey data that are available from 19 countries are combined in a meta-analysis (Table 1) the random-effects model summary effect for the risk of a genitally intact man having HIV is an odds ratio of 1.10 (95%CI=0.83- 1.46), indicating that on a general population level, circumcision has no association with risk of HIV infection.
Claiming that circumcision prevents HIV infections can lead people to engage in riskier behavior. Van Howe and Storms stated that circumcision has been marketed as the “natural condom” in some African countries, which may lead some men to not use condoms at all. More so, many men may not wait until they are fully healed before having sex, placing them at greater risk of infection.
Van Howe and Storms also noted that the RCTs results may come from selection bias:
The men attracted by a free circumcision to enroll in the RCTs are not representative of the general population. The RCT participants were required to want to be circumcised. A faithful monogamous man with a faithful spouse would have little motivation to seek a free circumcision. This selection bias may have resulted in enrollment of men more likely to engage in high-risk behaviors. The free circumcision and financial inducements may have added to the selection bias.
If the selection bias resulted in more men at high risk of infection being in the trial, then the results would apply only to men who engage in high-risk behaviors. This would be consistent with the observational studies finding that the association between circumcision status and HIV infection was present primarily in studies of high-risk men.
It is unclear what agenda the people pushing for circumcising all men truly have. The evidence clearly shows that circumcising men does not prevent or reduce sexually transmitted HIV infections, and in some regions in Africa the infections are not sexually transmitted to begin with, making circumcision pointless. Worse, most of those pushing for circumcision also tell men that they will still need to use condoms to prevent HIV transmission and other STDs. As Van Howe and Storms argued, “How rational is it to tell men that they must be circumcised to prevent HIV, but after circumcision they still need to use a condom to be protected from sexually transmitted HIV?”
It is irrational, and makes no sense for anyone to push for circumcising all men and boys when condoms provide instant and cheaper protection. Yes, some men and women may fight against using condoms. However, arguing that all males should be circumcised because some might not wear condoms is akin to saying all people should have their tonsils cut out because some people with colds and flus might not wash their hands.
There is simply no excuse for mutilating millions of boys and men’s bodies based on three incomplete, woefully questionable studies. Our time and money would be better spent providing education and condoms to people, and challenging the cultural norms that lead to people having unprotected sex.