Evidence has finally begun to emerge that circumcising men reduces rates of HIV among women. A recent cross-sectional study conducted in South Africa additionally found that women who said their last sexual partner was circumcised also had a lower rate of herpes simplex virus type 2 (HSV-2).

During the mid-2000s, a trio of randomized controlled trials proved that voluntary medical male circumcision (VMMC) lowers men’s risk of contracting the virus from women by about 60 percent. Public health experts have presumed that women would ultimately reap a benefit from the massive push in recent years to circumcise men in sub-Saharan Africa. But strong evidence supporting this hypothesis has been slow to come.

Researchers analyzed data from the HIV Incidence Provincial Surveillance System, an ongoing study of a representative sample of individuals from households in two subdistricts of KwaZulu Natal, South Africa.

Findings were presented at the 9th International AIDS Society Conference on HIV Science in Paris (IAS 2017).

Among the men in the survey, 51 percent of those ages 15 to 19 were circumcised, as were 45 percent of those ages 20 to 24 and 28 percent of those ages 25 to 29. In all the age brackets above 35, less than 20 percent of the men were circumcised. Just 10 percent of the overall group of men received a traditional circumcision, rather than a VMMC. (VMCC differs from traditional, ritualistic circumcision in that the penis’s foreskin is fully removed.)

The researchers analyzed data regarding 4,766 female members of the study group, who were 15 to 49 years old. Thirty-five percent said their most recent partner was circumcised; 65 percent said their most recent partner had an intact foreskin. The proportions of these two groups who tested positive for HIV were a respective 42 percent and 54 percent.

After adjusting the data for various factors, the researchers found that the women who reported that their most recent partner was circumcised were 29 percent less likely to have HIV and 22 percent less likely to have HSV-2 than the other women.

The study is limited by the fact that the women reported only about their most recent partner and not about any other partners. Also, women who said their partner was circumcised might have referred to a man who received a traditional circumcision, which requires only a partial removal of foreskin, conferring less of an HIV-related risk reduction to him.

To read the conference abstract, click here.

To watch a video of the conference presentation, click here.