Researchers have found that the human papillomavirus (HPV) vaccine may reduce the rate of oral HPV infections in young adults by as much as 88 percent. However, given the vaccine’s low rate of uptake in the U.S. – especially in males – the impact of the vaccine on oral HPV infections remains low.

This is the first study to explore the possible impact of HPV vaccination on oral HPV infections. The findings were presented by Maura L. Gillison, MD, PhD, professor, Thoracic/Head and Neck Medical Oncology at The University of Texas MD Anderson Cancer Center in advance of the American Society of Clinical Oncology’s 2017 Annual Meeting. The study was conducted while Gillison was at The Ohio State University Comprehensive Cancer Center.

Unfortunately, explained Gillison, no clinical trials have prospectively evaluated whether the existing FDA–approved HPV vaccines will prevent oral infections that lead to the disease. Therefore, the vaccine is not approved for the prevention for head and neck cancers. Gillison and her team analyzed data from the National Health and Nutrition Examination Survey (NHANES) – a study conducted by the National Center for Health Statistics designed to assess the health and wellness of the U.S. population. Since 2009, Gillison and colleagues have collaborated with NHANES to study oral HPV infections and have analyzed oral rinse samples collected by mobile health facilities.

For this current study, researchers analyzed data from 2011 – 2014; starting in 2011, participants began to self–report if they had received one or more HPV vaccines. Researchers analyzed responses from 2,627 young adults ages 18– 33, and compared the prevalence of an oral HPV infection in those who received one more doses of the vaccine to those who did not.

At that time, about 18.3 percent of young adults in the U.S. reported receiving one or more vaccine dose by age 26, with vaccination more common in women than men, 29.2 percent versus 6.9 percent, respectively.

In the cohort, the researchers evaluated the prevalence of HPV type 16, 8, 6 and 11 – the four types included in HPV vaccines prior to 2016.

The researchers observed that the prevalence of vaccine–type infections was far less common in individuals who had been vaccinated versus not vaccinated. When comparing the two groups, the infection rates in the vaccinated group was about 88 percent lower than in those individuals who had not been vaccinated.

Previous research had shown that this epidemic of HPV–positive head and neck cancers is disproportionately affecting men compared to women. So Gillison and her colleagues were particularly interested in looking at whether the vaccine appeared to be associated with a reduced prevalence of infection in men.

“When we compared the prevalence in vaccinated men to non–vaccinated men, we didn’t detect any infections in vaccinated men. The data suggests that the vaccine may be reducing the prevalence of those infections by as high as 100 percent,” said Gillison.

“We also wanted to determine, accounting for the low rates of vaccination, what proportion of infections could have been prevented,” said Gillison. “We found that just under 1 million people would have HPV infections in this age group, but, unfortunately, because of low–uptake of the vaccine, the burden of infection had only been reduced by 17 percent overall, and only seven percent in men. We hope the burden of infection will decrease over time with increased vaccination.”

A limitation of the study is that the research does not show a cause–and–effect relationship between this data and the reduction of the prevalence of infection.