Are circumcised men better protected against HIV?
(March 26, 2004, The Lancet)

A new study in India finds that uncircumcised men are more likely to contract HIV. This supports the theory that circumcision offers some measure of protection against the virus

Circumcised men are six to eight times less likely to contract HIV than men who aren’t circumcised, according to a report by American and Indian researchers in the prestigious medical journal The Lancet. The study, whose results replicate the findings of past research, suggests that the foreskin is highly susceptible to the HIV virus and men whose foreskin had been removed were less likely to become HIV-positive.

It’s claimed that circumcision reduces the risk of contracting HIV-1 by removing a possible entry point for the virus - the thinly keratinised mucosa of the inner foreskin and its HIV target cells.

Dr Robert C Bollinger and colleagues from the Johns Hopkins University Medical School, and the National AIDS Research Institute in Pune, India, tracked around 2,298 men who were being treated for various sexually-transmitted diseases (STDs) at three clinics in Pune. The men were confirmed HIV-negative at the start of the study. Their HIV status and risk behaviour patterns were regularly assessed.

However, the study also found that circumcised men were as much at risk of contracting STDs (syphilis, gonorrhoea and herpes simplex) as were uncircumcised men. “The specificity of this relation suggests a biological rather than behavioural explanation for the protective effect of male circumcision against HIV,” says Bollinger.

Commenting on the findings of the new study, Robert C Bailey, professor of epidemiology and biostatistics at the University of Illinois, in Chicago, says: “It is now about the ninth study that followed men who are HIV-negative over a period of months or years… which has found that the effect (of circumcision) is significant…The fact that they found no behavioural differences between the two groups is all the more compelling, and indicates that there is a biological factor.”

The association between circumcision and a reduced risk of HIV was noted as early as 1987, when Dr William Cameron of the University of Manitoba in Canada reported findings from a study in Kenya.

When AIDS first began to emerge in Africa, researchers found that it was more prevalent in the east and south of the continent than in the west. This was attributed to differences in sexual behaviour. Some scientists argued, however, that as the practice of circumcision was more common in West Africa it could be reducing the risk of HIV infection, as the foreskin could be more susceptible to the virus than other parts of the penis.

As circumcision did not appear to protect men against other STDs, Bollinger believes this study supports the hypothesis that protection resulted from the removal of the foreskin which contains cells that have HIV receptors which scientists suspect are the primary entry points for the virus into the penis.

“Our results suggest that the foreskin plays an important role in the biology of sexual transmission of HIV. The findings highlight the importance of developing compounds which block the entry of HIV at the cellular level,” Bollinger says.