Evidence of Herd Immunity to Oral HPV Infection Among Unvaccinated Men

Investigators at MD Anderson Cancer Center and the National Institutes of Health found evidence of herd immunity to oral infections from human papillomavirus (HPV).

The study, published in JAMA, found that rates of oral infections from the types HPV prevented by vaccines fell by 37% among unvaccinated men aged 18-59 years from 2009 to 2016.

Led by Maura L. Gillison, MD, PhD, a professor in the Department of Thoracic/Head and Neck Medical Oncology at the University of Texas MD Anderson Cancer Center in Houston, the study examined 4 vaccine types and 33 nonvaccine types of HPV and was conducted across 4 cycles of the National Health and Nutrition Examination Survey (NHANES).

The drop was noticed in vaccine types of HPV, which are most commonly associated with cancer. No difference was seen in nonvaccine types. There also was no difference among women, however, the study suggested that could reflect the low prevalence in women.

HPV vaccination rates increased from 0% to 5.8% in men and from 7.3% to 15.1% in women during the study period, suggesting that men are benefiting from the increase in vaccination among women.

Oral infection rates from vaccine-type HPV fell from 2.7% during the first NHANES survey to 1.6% during the last survey among unvaccinated men aged 18-59 years.

“These results are consistent with modeling and surveillance studies of herd protection against genital HPV infections in unvaccinated US females during 2004-2014,” the study noted.

HPV is associated with a number of cancers, including anal, oropharyngeal, cervical and penile cancers. About 80 million people in the United States are infected with some type of HPV, with about 14 million Americans becoming infected each year, according to the US Centers for Disease Control and Prevention (CDC). HPV causes about 35,000 cases of cancer each year.

Recent studies have shown a decrease in cervical cancer rates, associated with vaccination and herd immunity among women.

“Cervical cancer rates have been declining in the US for decades because of a successful screening program,” Gillison said in a statement issued by MD Anderson. “There is no analogous screening program for HPV-positive oral cancers. The vaccine is our current best hope for prevention. Our data underscore the importance of ongoing efforts to increase HPV vaccination rates in the US The entire population will benefit.”

In June, the CDC’s Advisory Committee on Immunization Practices voted to expand HPV vaccine recommendations to cover men up to age 26, allowing those who didn’t receive the vaccine in childhood to catch up to recommendations for vaccination.

The CDC recommends all boys and girls receive 2 doses of HPV vaccine at ages 11 or 12. For those who receive their first dose after age 15, 3 doses are recommended.

A recent study in Australia found that just 1 dose of the HPV vaccine protected as well as 2 or 3 doses against high-grade cervical pre-cancer. However, investigators advised practitioners to continue following the current recommendation pending further research.