Comparison of anal HPV natural history among men by country of residence: Brazil, Mexico, and the United States.

OBJECTIVES:Globally, anal cancer incidence is rare, but is increasing in some world regions. Our objective was to assess differences in anal HPV natural history in three countries. METHODS:Men aged 18-70 years were recruited from the US (n = 634), Mexico (n = 665), and Brazil (n = 731). Anal specimens were collected every six-months. HPV genotyping was assessed by Linear Array. Anal HPV prevalence was compared using the Fisher's exact test. HPV infection incidence rates (IR) and 95% confidence intervals (CI) were calculated. RESULTS:Any anal HPV prevalence was highest among men from Brazil (24%) compared to Mexico (15%) and the US (15%). When stratified by sexual history, the prevalence of any HPV among MSM/MSMW was 43%, 37%, and 45% and 9%, 12%, and 10% for MSW from Brazil, Mexico, and US, respectively. Any HPV incidence was significantly higher among men from Brazil compared to US men (IRR = 2.4, 95% CI = 1.7-3.4) and comparable between men from Mexico and the US (IRR = 1.2, 95% CI = 0.8-1.8). CONCLUSION:Men in Brazil and Mexico often have similar, if not higher incidence of anal HPV compared to men from the U.S., and may benefit from gender neutral HPV vaccine policies.