Prophylactic human papillomavirus (HPV) vaccination significantly reduced vaccine-type oral HPV infections among young adults, according to the results of a cross-sectional study (abstract 6003) presented at a press conference ahead of the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting.
The prevalence of high-risk oral HPV infection was 88.2% lower in adults who had undergone vaccination compared with those who had not.
“HPV is now appreciated to be the cause of cancers that arise from the tonsils and the base of the tongue known as oropharynx,” said Maura L. Gillison, MD, PhD, professor of medicine at the University of Texas MD Anderson Cancer Center, during the press conference. Gillison conducted the research while at Ohio State University. “This is the fastest rising cancer in young white men in the United States and over 90% of these cancers are caused by a single type, HPV 16, one of the types covered in the currently recommended HPV vaccines.”
Gillison and colleagues conducted this study to determine the effect of HPV vaccination on oral HPV infections in the US population. They included 2,627 adults aged 18 to 33 from the National Health and Nutrition Examination Survey, 2011–2014. This was the first group of young adults eligible to receive the HPV vaccine. Prevalence of infection was compared between those with self-reported receipt of one or more doses of the HPV vaccine compared with unvaccinated individuals.
During the study period, less than one in five (18.3%) of the US population aged 18 to 33 reported receiving one or more dose of the HPV vaccine prior to age 26. The rate of vaccination was significantly higher among women compared with men (29.2% vs 6.9%; P < .001).
Nevertheless, the prevalence of oral HPV 16/18/6/11 infections—the four HPV types included in the vaccine prior to 2016—was significantly reduced in vaccinated compared with unvaccinated adults (0.11% vs 1.61%; P = .008). The prevalence of the 33 non-vaccine HPV types was similar between the two groups.
The researchers also saw a significant reduction in oral HPV infection in vaccinated compared with unvaccinated men (0.0% vs 2.1%; P = .007), which is important because oral HPV infection rates are rising dramatically among men, Gillison said.
“The vaccines could be reducing oral HPV infections by as much as 88% overall in vaccinated populations and as high as 100% among men,” Gillison said. “There is tremendous potential to prevent oral HPV 16/18/6/11 infection.”
The researchers estimated that about 1 million people in the United States could have one of these types of oral HPV infection.
“If the vaccine was universally accepted we could have prevented over 900,000 of those,” Gillison said. “Factoring in the low uptake as of 2014, we estimated that only 17% of potentially preventable infections had been prevented; 25% in women and a modest 7% in men.”