Research conducted in Kenya has demonstrated that adult male circumcision protects against acquisition of high viral-load infections of the glans penis with high-risk human papillomavirus (HPV). Circumcision also results in greater clearance of high viral-load HPV infections acquired precircumcision.

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High-risk subtypes HPV16 and HPV18 are associated with penile cancer and cervical cancer; high viral loads of HPV in men are thought to cause increased viral transmission to female partners. Previous studies have shown that male circumcision is protective against acquisition of high-risk HPV infection, but have not investigated the effect of this intervention on viral load in the penis.

Senkomago and colleagues have now conducted a randomized, controlled trial to determine the effectiveness of male circumcision on acquisition and clearance of high viral-load HPV infections. The primary interest of the trial was the effect on HIV incidence. Sexually active, uncircumcised men aged 18–24 years were enrolled between 2002 and 2005. The men were randomly allocated to the circumcision (1,159 men) and control (1,140 men) arms. In the control group, circumcision was postponed for the 24 months of the study observation. The presence, subtype and viral load of high-risk HPV were determined at baseline and every 6 months, using penile swabs from glans and shaft sites.

For high-risk HPV identified at baseline, the 6-month risk of persistence for high viral-load infections (>250 viral copies per swab) in the glans was lower in the circumcision arm than the control for both HPV16 (risk ratio [RR] 0.36) and HPV18 (RR 0.34). The rate of acquisition of high viral-load infection in the glans was also lower in the circumcision arm than in the control arm for both HPV16 (HR 0.32) and HPV18 (HR 0.34). For acquired infections in the glans, the prevalence of high versus low viral-load infections at the time of detection was lower in the circumcised group than the control for HPV16 (prevalence ratio [PR] 0.70) and HPV18 (PR 0.59). Results for samples from the penile shaft were not comparable.

These results add to the evidence for a protective effect of male circumcision against high-risk HPV, in both men and women.