After the highly publicized halting of research trials looking at the impact of circumcision on HIV infection among African men (the trials were stopped because early data showed such a large protective effect that it was deemed unethical not to immediately circumcise all the participants) researchers have been analyzing the data for more clues as to why male circumcision offers such a dramatic reduction in risk of HIV transmission.
The methodological and ethical questions about the research remain unanswered and as far as I've read unaddressed, which in some ways makes it even more important for us to keep following the research.
Last week researchers at Johns Hopkins University published a paper in PLoS Medicine, parsing out one aspect of the protection, the relationship between circumcision, genital ulcers, and the herpes simplex virus that causes sores (HSV-2). From the study:
Genital ulcer disease, particularly when caused by HSV-2, is thought to increase a person's risk of acquiring HIV, so could male circumcision reduce HIV transmission rates because of its beneficial effects on genital ulcer disease rather than through its removal of foreskin tissue with its rich source of HIV target cells?
The researchers analyzed data from the study including which men came into the study with and without herpes, which men got herpes during the study, and which men who developed genital sores (sometimes caused by herpes, sometimes not) during the study. The men were examined at 6, 12, and 24 months during the study.
They found that circumcision cut risk of genital ulcers almost in half, whether men had herpes at the beginning of the study or not. They also found that while circumcision reduced the risk of HIV in men without herpes it didn't reduce the risk of acquiring HIV in men who had herpes at the beginning of the study.
Their analysis leads them to suggest that circumcision protects against genital sores mostly by reducing the risk of sores developing from "mild trauma during intercourse" and that the protective effect of male circumcision against HIV is primarily due to the removal of what they call "vulnerable foreskin tissue containing HIV target cells" and not because circumcision protects against other STDs which in turn increase the chances of acquiring HIV.
This is interesting stuff, even if it's early on in the theorizing of it. It would be nice if the researchers pursued a parallel agenda of addressing the ethical concerns raised by such highly racialized research (or you know, at least acknowledged it).
Read more - Gray RH, Serwadda D, Tobian AAR, Chen MZ, Makumbi F, et al. (2009) Effects of Genital Ulcer Disease and Herpes Simplex Virus Type 2 on the Efficacy of Male Circumcision for HIV Prevention: Analyses from the Rakai Trials. PLoS Med 6(11): e1000187. doi:10.1371/journal.pmed.1000187
Related - About Herpes ; About HIV/AIDS
