Observational studies and a small collection of randomized controlled trials (RCTs) suggest that male circumcision may significantly reduce HIV transmission between sero-discordant contacts. The Joint United Nations Programme on HIV/AIDS (UNAIDS) and World Health Organization have recently announced recommendations to scale up male circumcision in countries with generalized epidemics and low levels of male circumcision. However, no meta-analysis has been conducted to determine the effectiveness of this intervention.
We conducted a systematic review of medical literature, and included any RCTs assessing male circumcision to prevent heterosexually acquired HIV infection among males. We used the DerSimonian–Laird random effects method to pool study outcomes. We calculated the relative risk (RR), risk difference, number needed to treat (NNT) and I2, all with 95% confidence intervals (CIs).
We identified three RCTs that met our inclusion criteria, involving a total of 11 050 men. The pooled RR was 0.44 (95% CI 0.33–0.60, P<0.0001, I2=0%, 95% CI 0–35%). The risk difference was 0.014 (95% CI 0.07–0.21), yielding a NNT of 72 (95% CI 50–143).
Male circumcision is an effective strategy for reducing new male HIV infections. Its impact on a population level will require consistently safe sexual practices to maintain the protective benefit.