HPV Vaccination Has Potential to Substantially Reduce Infections But Improved Uptake Needed
Prevalence of oral HPV infection among vaccinated persons was 0.11% vs 1.61% in unvaccinated persons, researchers report.
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A comparison of prevalence of vaccine-type oral human papillomavirus (HPV) infection in vaccinated vs unvaccinated young adults demonstrated that HPV vaccination can reduce infection rates significantly, according to study results to be presented at the 2017 American Society of Clinical Oncology Annual Meeting.1,2
Current indications for HPV vaccination are for the prevention of cervical, vulvar, vaginal, and anal cancers in women and anal cancers in men. In recent decades, incidence of HPV-positive oropharyngeal cancer has increased among US men. However, no studies have evaluated the potential impact of HPV vaccination on oral HPV infections.
Therefore, Maura L. Gillison, MD, PhD, of the MD Anderson Cancer Center, and colleagues conducted a cross-sectional study of men and women in the National Health and Nutrition Examination Survey (NHANES) aged 18 to 33 years in 2011-2014 (n = 2627) to evaluate the impact of prophylactic HPV vaccination on oral HPV infections.2
The researchers evaluated self-reported receipt of 1 or more vaccine-doses on prevalence of oral infection with HPV among vaccinated vs unvaccinated persons, percent reduction in infection prevalence among vaccinated persons, and population-level effectiveness of vaccination. In this study, HPV strains evaluated were types 16, 18, 6, and 11, the four strains for which there was a vaccine prior to 2016 (a newer vaccine that protects against an additional 5 HPV strains was introduced at that time).
Comparisons were conducted using binary logistic regression, adjusting for age, gender, and race. Statistical significance was assessed using a quasi-score test.
Among the study population, 18.3% (29.2% of women, 6.9% of men; P <.001) reported receiving 1 or more HPV vaccine-dose prior to age 26 years. Prevalence of oral HPV infection among vaccinated persons was 0.11% vs 1.61% in unvaccinated persons (P =.008), a significant reduction that corresponded to an estimated 88% (95% CI, 5.7%-98.5%) reduction in prevalence among the vaccinated persons.
Notably, prevalence was significantly reduced in vaccinated men vs unvaccinated men (0.0% vs 2.13%; P =.007). A similar prevalence was seen in the 33 HPV strains for which there is no vaccine (3.98% vaccinated vs 4.74% unvaccinated; P =.24).
Vaccine uptake in the United States is low; therefore, population-level effectiveness on the burden of oral HPV infection is a modest 17% overall (25% in women, 6.9% in men), explained Dr Gillison.
The researchers conclude that HPV vaccination may substantially reduce vaccine-type oral HPV infection prevalence among young adults. However, low vaccine uptake limited the population-level impact. They note that clinical trials would be required to demonstrate a cause-effect.
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1. Gillison ML, Broutian T, Graubard B, et al. Impact of prophylactic human papillomavirus (HPV) vaccination on oral HPV infections among young adults in the U.S. Oral presentation at: 2017 American Society of Clinical Oncology Annual Meeting; June 2-6, 2017; Chicago, IL. Abstract 6003.
2. HPV vaccination may reduce oral HPV infections — but still under-utilized [news release]. Alexandria, VA: American Society of Clinical Oncology; May 17, 2017.