The effectiveness of male circumcision for HIV prevention and effects on risk behaviors in a posttrial follow-up study.
BACKGROUND
The efficacy of male circumcision for HIV prevention over 2 years has been demonstrated in three randomized trials, but the longer-term effectiveness of male circumcision is unknown.


METHODS
We conducted a randomized trial of male circumcision in 4996 HIV-negative men aged 15-49 in Rakai, Uganda. Following trial closure, we offered male circumcision to control participants and have maintained surveillance for up to 4.79 years. HIV incidence per 100 person-years was assessed in an as-treated analysis, and the effectiveness of male circumcision was estimated using Cox regression models, adjusted for sociodemographic and time-dependent sexual behaviors. For men uncircumcised at trial closure, sexual risk behaviors at the last trial and first posttrial visits were assessed by subsequent circumcision acceptance to detect behavioral risk compensation.


RESULTS
By 15 December 2010, 78.4% of uncircumcised trial participants accepted male circumcision following trial closure. During posttrial surveillance, overall HIV incidence was 0.50/100 person-years in circumcised men and 1.93/100 person-years in uncircumcised men {adjusted effectiveness 73% [95% confidence interval (CI) 55-84%]}. In control arm participants, posttrial HIV incidence was 0.54/100 person-years in circumcised and 1.71/100 person-years in uncircumcised men [adjusted effectiveness 67% (95% CI 38-83%)]. There were no significant differences in sociodemographic characteristics and sexual behaviors between controls accepting male circumcision and those remaining uncircumcised.


CONCLUSION
High effectiveness of male circumcision for HIV prevention was maintained for almost 5 years following trial closure. There was no self-selection or evidence of behavioral risk compensation associated with posttrial male circumcision acceptance.