Oral infection with human papillomavirus (HPV) is common among gay men, Dutch investigators report in the online edition of AIDS. Prevalence was especially high among HIV-positive gay men, who were also more likely to be infected with the strains of HPV associated with a high-risk of cancers of the head and neck.
“This study demonstrates a high HPV prevalence in the oral cavity of sexually active MSM [men who have sex with men], and particularly in HIV-infected MSM,” write the authors.
They believe their research suggests that HIV-positive men would be especially likely to benefit from HPV vaccination.
HPV is the most common sexually transmitted viral infection. Some strains of HPV are associated with an increased risk of anogenital cancers and also cancers of the head and neck (oropharyngeal).
Rates of oropharyngeal cancers are increasing, especially among gay men. However, little is known about the prevalence of oral HPV infection and its risk factors among gay and other MSM.
Investigators in Amsterdam therefore designed a study involving 767 gay men, 41% of whom had HIV.
The study was conducted between 2010 and 2011. Data were gathered regarding smoking history, a recognised risk factor for oral cancers. The men also completed questionnaires about their sexual behaviour.
Oral-rinse and gargle specimens were analysed for the presence of HPV DNA. A highly sensitive PCR assay was used to establish the prevalence of infection with HPV strains most associated with oral and anogenital cancers.
The study participants had a median age of 40 years. Overall, the participants with HIV were more likely to report risky sexual behaviour. In addition, participants with HIV were more likely to report smoking cigarettes and the use of cannabis and poppers.
Most (87%) of the men with HIV were taking antiretroviral therapy, 78% had an undetectable viral load and the median CD4 cell count was 535 cells/mm3.
Overall, 40% of samples were positive for HPV DNA. Prevalence differed by HIV status and was significantly higher among the men with HIV (57 vs 27%, p < 0.001).
It was possible to genotype 24% of samples, and prevalence was once again significantly higher among the men with HIV (39 vs 15%, p < 0.001).
A quarter of HIV-positive men had oral infection with high-risk strains of HPV (25%). This was significantly higher (p < 0.001) than the 9% prevalence observed in HIV-negative men.
Prevalence of infections with multiple strains of HPV was also elevated in the men with HIV (15 vs 3%, p < 0.001), as was infection with HPV-16, which has been associated with an especially high risk of oral cancer (5 vs 2%, p = 0.01).
After taking into account age, smoking habits and sexual behaviour, HIV infection was associated with a twofold increase in the risk of oral HPV infection (aOR = 2.6; 95% CI, 1.6-4.1).
HIV infection was also associated with infection with an HPV strain than could be genotyped (aOR = 2.8; 95% CI, 1.9-4.2) and with infection with multiple HPV strains (aOR = 5.1; 95% CI, 2.5-10.2).
“HIV infection was strongly and independently associated with oral HPV infection,” the investigators comment. They suggest this could be because of “higher HPV exposure due to more sexual high-risk behaviour…an increased susceptibility for HPV infection in the oral cavity, and an increased HPV persistence due to immunosuppression.”
In HIV-negative men, older age, recent use of poppers, a higher number of sexual partners and recent oral and/or anal sex were all associated with an increased risk of oral infection with high-risk HPV strains. However, after controlling for potential confounders, only older age remained significant (p = 0.036).
Risk factors for infection with high-risk strains for men with HIV included smoking (p = 0.002) and use of cannabis in the past six months (p = 0.04). However, neither of these factors remained significant in the multivariate analysis.
The investigators call for further research “to assess the factors affecting the natural history of HPV infection, including HIV, and the subsequent risk of developing HPV-related head and neck cancer”.
They also suggest that vaccination against HPV could be of value “particularly for HIV-infected men and others at increased risk of HPV-related head and neck cancer”.
Mooij SH et al. Oral human papillomavirus infection in HIV-negative and HIV-infected men who have sex with men: the HIV & HPV in MSM (H2M) study. AIDS 27, online edition. DOI: 10.1097/QAD.0b013e328362395c, 2013.