An increase in female HPV vaccination in the United States appears to have provided unvaccinated men aged 18 to 59 years herd protection against vaccine-type oral HPV infections, according to findings published today in JAMA. No such herd protection was recorded among unvaccinated women.
Routine HPV vaccination has been recommended in the U.S. since 2006 for women and 2011 for men, the authors of the report noted.
“Although studies have demonstrated high vaccine efficacy in reducing prevalence of oral HPV infection, prevention of oral HPV infections and oropharyngeal cancers is not a vaccine indication because of lack of randomized trials. Also lacking are surveillance studies for herd protection against oral HPV infections,” Anil K. Chaturvedi, PhD, senior investigator in the division of cancer epidemiology and genetics at the National Cancer Institute, and colleagues wrote.
Chaturvedi and colleagues conducted a study of unvaccinated U.S. men and women aged 18 to 59 years using data collected from the National Health and Nutrition Examination Survey. They compared the prevalence of oral HPV during four periods from 2009 to 2016 for four vaccine types and 33 non-vaccine types.
From 2009 to 2016, vaccination rates increased from 0% to 5.8% in men and from 7.3% to 15.1% in women. Among unvaccinated men aged 18 to 59 years, the prevalence of vaccine-type oral HPV was 2.7% in 2009-2010 and declined to 1.6% in 2015-2016 (adjusted prevalence ratio = 0.63; 95% CI,0.44-0.9). According to the researchers, the observed decline “was not heterogeneous by age” (P = .41) and the prevalence of nonvaccine-type oral HPV remained unchanged among unvaccinated men.
The prevalence of oral HPV among unvaccinated women aged 18 to 59 years remained unchanged for vaccine (0.6% in 2009-2010 vs. 0.5% in 2015-2016; adjusted PR, 0.96; 95% CI, 0.23-3.98) and nonvaccine types (2.6% in 2009-2010 vs. 3.3% in 2015-2016; adjusted PR, 1.29; 95% CI, 0.71-2.35), although the researchers noted that the study may have lacked the statistical power to note any herd protections.
“The estimated herd protection should be incorporated into evaluations of the cost-effectiveness of HPV vaccination of men older than 26 years,” Chaturvedi and colleagues wrote. “Vaccine trials of oral HPV incidence and persistence in men should inflate sample sizes to account for herd protection.” – by Marley Ghizzone
Disclosures: Chaturvedi reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.