To determine if the human papillomavirus (HPV) vaccination offers cross-protection against nonvaccine HPV types and whether introduction of the vaccination has offered herd immunity to unvaccinated women.
We collected and analyzed HPV prevalence data for females aged 18–29 from the prevaccine era (2007–2008) and postvaccine era (2009–2012) using the National Health and Nutrition Examination Surveys (NHANES); 1628 female respondents aged 18–29, representing 21,135,134 females in the United States non-institutionalized civilian population, provided vaginal swabs across three consecutive NHANES survey cycles.
Among females aged 18–29, the prevalence of high risk HPV among women who received at least one dose of the HPV vaccine decreased from 67% (95% confidence interval [CI] 50.7–81.4) in 2007–2008 to 41.5% (95% CI, 30.5–53.1) in 2011–2012; among the women vaccinated for HPV in the postvaccine era, the prevalence of HPV-16 and -18 was 6.4% versus 93.6% for all other high risk HPV types. There was no difference in prevalence in high risk HPV for women who did not receive the vaccine; 49.5% (95% CI, 42.5–56.6) in 2007–2008 versus 50.8% (95% CI, 43.0–58.7) in 2011–2012.
The prevalence of high risk HPV significantly decreased among females aged 18–29 years who received the HPV vaccine, but there appeared to be no cross-protection against nonvaccine HPV types. These findings may offer support for usage of the investigational 9-valent HPV vaccine. There also was no evidence to suggest protection against HPV infection for unvaccinated women.
Womack Army Medical Center, Fort Bragg, NC
Financial Disclosure: The authors did not report any potential conflicts of interest.