The introduction of risk-reducing technology can lead to unintended consequences, especially when risk compensation can be one of potential operating mechanism to offset the positive impact. For male circumcision, its preventive effect against HIV infection might diminish if circumcised men engage in riskier sexual behaviors. The purpose of this study is to investigate risk-compensating behavior after medical male circumcision in the long run. We randomly provided free male circumcision surgery to 2,667 adolescent male students at secondary schools in Malawi and conducted long-term follow-up survey after about four years. We find that male students who received the offer more intensively were 35 percent more likely to be infected with HSV-2 than the other students, suggesting riskier sexual behavior after circumcision. Self-reported sexual behavior, meanwhile, are showing little-to-no evidence of practicing riskier sex after circumcision, except for the inconsistent use of condom.

...and that in the long term, circumcising infants or adolescent boys (younger than 19 years of age) would result in the largest impact..
As implementers rolled out VMMC programs in Zimbabwe and the other VMMC priority countries in eastern and southern Africa, it became evident that recruiting adolescents ages 10–19 was much easier than recruiting adult men for VMMC...
Furthermore, the relative proportion of clients ages 10–14 has been increasing over time, whereas the proportion of clients over age 20 has been decreasing.

Although increased investment in recruiting VMMC clients ages 20–29 may lead to greater overall impact if recruitment efforts are successful, it may also lead to lower cost-effectiveness, depending on the cost of increasing recruitment.

This manuscript is made possible by the generous support of the American people through the United States President’s Emergency Plan for AIDS Relief (PEPFAR) with the United States Agency for International Development (USAID)