Background:  Human papillomavirus (HPV) causes a subset of oropharyngeal cancers but the prevalence and risk factors for oral HPV infection are not well understood. Initial studies suggest HIV-infected individuals have an increased incidence of HPV-related cancers including oropharyngeal cancer.  More than 90% of HPV-associated oropharyngeal cancer is caused by a single HPV type, HPV16.

Methods:  Oral exfoliated cells were collected using a swish and gargle with 10ml of Scope mouthwash in 149 HIV-infected and HIV-uninfected men who have sex with men (MSM) in the Baltimore center of the MACS. We hypothesized that MSM are high risk because of a high number of oral sexual partners. Samples were tested for 37 types of HPV DNA using PGMY09/11 consensus primers and line blot hybridization. Logistic regression was used to explore risk factors for infection.

Results:  Prevalent oral HPV infection was common among HIV-infected (39%) and HIV-uninfected MSM (28%). HPV16 was the most common HPV type detected and was found in 13% of MSM overall (8.2% of HIV-infected and 16% of HIV-uninfected MSM). Other oncogenic oral HPV infections detected included HPV66, 68, 83 (2.0% prevalence each), 45, 53, 58, 59, 73 (1.3% each). In this group of MSM, 40% reported multiple oral sex partners in the past 6 months. Oral HPV prevalence was non-significantly higher among those with 2 or more than those with 0 to 1 recent oral sexual partners (39% vs 30%, P =0.29). The majority of HIV-infected participants were currently on HAART (75%), had CD4 cell count>500 (65%) and HIV viral load <500 copies/mL (89%). Oral HPV prevalence was comparable among current and never HAART users (41% vs 40%) and was not associated with current CD4, or HIV viral load. Among HIV-infected MSM oral HPV prevalence was associated with younger age (66% prevalence in <45 year olds vs 20% in those over 65 years, p-trend = 0.035), current marijuana use (64% vs 34%, P =0.07) and not drinking alcohol (59% among never drinkers vs 21% among weekly/daily drinkers, P =0.07). In multivariate analysis HIV-positive current marijuana users were 10-times more likely (P =0.05) and current alcohol users were 10x less likely (P =0.02) to have prevalent oral HPV infection.

Conclusions:  Oral HPV16 prevalence is alarmingly high among MSM suggesting they may be at increased risk for HPV-associated oropharyngeal cancers. Oral HPV prevalence was similar among HAART users and non-users suggesting HAART may not improve oral HPV clearance.