Men who have sex with men (MSM) are at risk for human papillomavirus (HPV)-related anal cancer. Few data exist on antibody responses following incident anogenital infection with HPV in teenage MSM. A cohort of 200 MSM aged 16-20 years from Melbourne, Australia were assessed at baseline, 3, 6 and 12 months. At each visit anal and penile swabs were collected for HPV DNA and serum for HPV antibodies for genotypes 6, 11, 16 and 18 (Merck's Multiplex Assays using Luminex). The main outcome, seroconversion, was defined as the detection of HPV antibodies following a negative antibody result for the same HPV type at baseline. The seroincidence rates for HPV types 6, 11, 16 and 18 were: 19 (95% CI 12-26), 7 (3-12), 4 (1-8) and 6 (3-11) per 100 person-years, respectively. Men who experienced incident anal HPV infections from types 6/11 were significantly more likely to develop serum antibodies to the same HPV type(s) than those who experienced incident anal infections from types 16/18 [73 vs. 18%, odds ratio (OR) 5 15, 95% CI: 2-118]. The median time between incident anal HPV infection and seroconversion for HPV 6, 11, 16 and 18 was: 91, 38, 161 and 182 days, respectively. Antibody responses against HPV types 6/11 were significantly more likely to occur following incident anal compared with incident penile infection with HPV types 6/11 (OR 5 6, 95% CI: 2-21). The likelihood of antibody responses following anogenital HPV infections depends on the HPV type and site of infection.Human papillomavirus (HPV) infection is common among men who have sex with men (MSM) and a cause of anogenital warts as well as anal cancer.1 Anal cancers are overrepresented among HIV positive MSM.2 Anogenital warts are most commonly caused by HPV types 6 and 11. The majority of anal cancers are caused by HPV types 16 and some anal cancers are caused by HPV types 18. In men the quadrivalent HPV vaccine is effective at preventing infection with HPV types 6, 11, 16 and 18 and related anogenital lesions.
3With high coverage of the target population HPV vaccination should help to prevent anal cancer. 4 Data suggest that in some populations of MSM the incidence of anal cancer has increased.5 This includes increases in the incidence of anal cancer among HIV positive MSM despite the greater uptake of anti-retroviral treatment (ART) which has been associated with a fall in other HIV-associated cancers. 6,7 Data from the US National Cancer Institute show that the 5-year survival for patients diagnosed with anal cancer to be 65.7% with poorer outcomes for more advanced cancers.
8Although only a proportion of anogenital HPV infections elicit a serum antibody response, antibodies following natural Key words: human papillomavirus (HPV), men who have sex with men, seroprevalence, seroincidence, antibody Abbreviations: AIN: anal intraepithelial neoplasia; ART: anti-retroviral treatment; CI: confidence intervals; HPV: human papillomavirus; IQR: interquartile range; MSM: men who have sex with men; OR: odds ratio; SEER: surveillance, epidemiology, and end results pro...