The Role of Male Circumcision in the Prevention of Human Papillomavirus and HIV Infection

Two articles in this issue of the Journal [ 1, 2] add to the growing body of evidence that male circumcision may reduce carriage of penile human papillomavirus (HPV). The first article [1] is a secondary analysis from a randomized trial of male circumcision for HIV prevention among South African men aged 18-24 years. The investigators reported that, after 21 months of follow-up, the point prevalence of high-risk HPV (HR-HPV) in urethral swab samples was 14.8% among men in the intervention arm compared with 22.3% in uncircumcised control subjects. The adjusted prevalence rate ratio (PRR) was 0.66 (95% confidence interval [CI], 0.51-0.86), suggesting a 34% efficacy. There are limitations to these trial data, however, because HPV infection was assessed only in a subsample of men seen at their 21 -month visits during a limited period of time and not at enrollment or at any intermediate follow-up visits. This raises 2 concerns. First, a possible lack of baseline comparability can-