Oral Human Papillomavirus (HPV) Prevalence and Abundance in the UK Young Adult Population

BACKGROUND: The incidence rates of HPV positive oropharyngeal cancers (OPSCCs) are on the rise, yet oral HPV prevalence rates in clinically healthy populations are poorly understood. To determine the risk of healthy adults developing OPSCCs, first we must establish oral HPV prevalence, viral load, persistence, and clearance rates in healthy populations to understand the link between oral HPV and OPSCCs. This is even more pertinent within the young adult population as the HPV vaccination programme has been shown to reduce cervical cancer incidence but not OPSCC incidence. Therefore, other factors that could affect oral HPV contraction and OPSCC development need investigation such as population demographics, lifestyle risk behaviours, HPV screening methods and vaccination status.
OBJECTIVES: The aims of this study were centred on establishing reproducible and sensitive HPV screening methods for the detection of oral HPV in clinically healthy young adults, for determining prevalence and abundance, and establishing if oral HPV was influenced by vaccination status, demographics, and lifestyle risk behaviours.
METHODS: The study established a novel and sensitive real-time PCR HPV consensus screening method for the detection of multiple HPV subtypes in the oral cavity of 408 clinically healthy UK-based young adults (92.01%; 18-25 years old in 2016-17). HPV positive or undetermined samples were then screened using qPCR for HPV subtypes, HPV-6, HPV-11, HPV-16, HPV-18. All results were analysed alongside vaccination status, demographics and lifestyle risk behaviour data collected via questionnaire.
RESULTS: An oral HPV prevalence rate of 22.79% was found, with HPV-16 being the most prevalent and abundant subtype at 19.12%; 1.08x105 copies/million cells, followed by HPV-18 at 1.72%; 1.89x104 copies/million cells, HPV-6 at 0.49%; 4.50x102 copies/million cells and HPV-11 at 0.25%; 1.06x102 copies/million cells. Unknown HPV subtypes were detected in 2.21% of the cohort. Oral HPV was found to be significantly associated with open-mouth kissing (p <.001), oral sex (p = .049), masturbation in males (p = .020), sexual intercourse (p = .026), sexual activity diversity (p = .043), frequent smoking (p = .024), wine drinking (p = .045) and drinking ≥2 types of alcohol per sitting (p = .015), especially in males (p = .023). HPV-16 was significantly associated with masturbation (p = .004), whilst there was a reduction in viral load in vaccinated individuals, but this was not statistically significant.
CONCLUSIONS: Oral HPV is prevalent in the young adult UK population, especially HR-HPV subtype HPV-16, questioning the efficacy of the HPV vaccination on reducing oral prevalence. However, HPV vaccination may instead influence oral HPV viral load, but further research is required, demonstrating the importance of measuring both presence and abundance. Oral HPV prevalence did appear to be influenced by sexual practice, including open-mouth kissing and oral sex, but less so by smoking and alcohol consumption, reaffirming the link between oral HPV and OPSCCs.