ATLANTA — Since the HPV vaccine was first introduced in the United States in 2006, researchers observed a 71% decline in the prevalence of the four HPV types targeted by vaccination among girls aged 14 to 19 years in 2014. HPV prevalence also decreased by 61% among young women aged 20 to 24 years.
The data, which were presented at CDC’s Epidemic Intelligence Service (EIS) Conference, demonstrated an even higher decline of 91% among vaccinated girls and young women aged 14 to 24 years who report being sexually active.
Sara E. Oliver
“This study shows in a nationally representative population that the HPV vaccination program has reduced vaccine-type HPV among teen girls and young women. This adds to the body of evidence that vaccination can prevent HPV infections that can cause cancer,” Sara E. Oliver, MD, MSPH, an EIS officer for the CDC, told Infectious Disease News. “We’ve seen the largest reductions in vaccinated females, but we are also seeing declines among unvaccinated females, which is an extra benefit of the vaccination program.”
Oliver and colleagues used vaccination data from the National Health and Nutrition Examination Surveys and HPV DNA from self-collected cervicovaginal specimens to estimate the prevalence of HPV-6, -11, -16, and -18 types that are covered by the quadrivalent vaccine (4vHPV, Gardasil, Merck), which was administered more often than the bivalent vaccine, Cervarix (GlaxoSmithKline), through 2014, Oliver said. The researchers then compared estimated rates of 4vHPV-type prevalence among sexually active women aged 14 to 24 years in the pre-vaccine era (2003 to 2006), early vaccine era (2007 to 2010) and recent vaccine era (2011 to 2014).
According to the data, approximately 51% of sexually active women aged 14 to 24 years received at least one dose of the HPV vaccine from 2011 to 2014. The prevalence of vaccine-type HPV declined from 18.5% in the pre-vaccine era to 7.1% in the recent vaccine era (adjusted prevalence ratio [aPR] = 0.33; 95% CI, 0.23-0.49). In vaccinated women, the 4vHPV-type prevalence in the recent vaccine era was 2% (aPR = 0.09; 95% CI, 0.04-0.2) vs. 12.2% among unvaccinated women (aPR = 0.6; 95% CI, 0.37-0.98).
Although there were no significant reductions in 4vHPV-type prevalence among older age groups, Oliver reported that the 40% reduction in HPV among unvaccinated women, which was likely due to herd protection, further supports the use of the HPV vaccine.
“This is the first national study in the United States that showed a decrease in [HPV prevalence among] unvaccinated females,” Oliver said. “This continues to provide support that the HPV vaccination program is working and that clinicians need to continue to provide a strong recommendation for HPV vaccination for adolescent males and females.” – by Stephanie Viguers
For more information:
CDC. Why is HPV Vaccine Important? 2017. https://www.cdc.gov/hpv/hcp/hpv-important.html. Accessed April 24, 2017.
CDC. For Clinicians. 2017. https://www.cdc.gov/hpv/hcp/index.html. Accessed April 24, 2017.
Oliver SE, et al. Prevalence of Human Papillomavirus Before and After Vaccine Introduction — National Health and Nutrition Examination Surveys, United States, 2003-2014. Presented at Epidemic Intelligence Service Conference: April 24-27; Atlanta.
Disclosure: The researchers report no relevant financial disclosures.
Editor’s note: The age groups of the study population and data on the incidence of HPV were updated on May 2.