Incidence and clearance of genital human papillomavirus infection in men (HIM): a cohort study.

BACKGROUND: Human papillomaviruses (HPVs) cause genital warts and cancers in men. The natural history of HPV infection in men is largely unknown, and that information is needed to inform prevention strategies. The goal in this study was to estimate incidence and clearance of type-specific genital HPV infection in men, and to assess the associated factors.

METHODS: Men (aged 18-70 years), residing in Brazil, Mexico, and the USA, who were HIV negative and reported no history of cancer were recruited from the general population, universities, and organised health-care systems. They were assessed every 6 months for a median follow-up of 27·5 months (18·0-31·2). Specimens from the coronal sulcus, glans penis, shaft, and scrotum were obtained for the assessment of the status of HPV genotypes.

FINDINGS: In 1159 men, the incidence of a new genital HPV infection was 38·4 per 1000 person months (95% CI 34·3-43·0). Oncogenic HPV infection was significantly associated with having a high number of lifetime female sexual partners (hazard ratio 2·40, 1·38-4·18, for at least 50 partners vs not more than one partner), and number of male anal-sexual partners (2·57, 1·46-4·49, for at least three male partners vs no recent partners). Median duration of HPV infection was 7·52 months (6·80-8·61) for any HPV and 12·19 months (7·16-18·17) for HPV 16. Clearance of oncogenic HPV infection decreased in men with a high number of lifetime female partners (0·49, 0·31-0·76, for at least 50 female partners vs not more than one partner), and in men in Brazil (0·71, 0·56-0·91) and Mexico (0·73, 0·57-0·94) compared with the USA. Clearance of oncogenic HPV was more rapid with increasing age (1·02, 1·01-1·03).

INTERPRETATION: The data from this study are useful for the development of realistic cost-effectiveness models for male HPV vaccination internationally.

FUNDING: National Cancer Institute.