Decreases in human papillomavirus vaccine types 16 and 18 in cervical precancers — HPV-IMPACT, 2008–2019

BACKGROUND: Monitoring human papillomavirus (HPV) types detected in cervical precancers has been one approach to evaluate HPV vaccination impact in the United States. During 2008-2014, the proportion of cervical precancers positive for HPV16/18 decreased overall and among some demographic and histologic subgroups. This updated analysis describes trends through 2019. METHODS: We analyzed cervical precancers among women aged 20-39 years from a 5-site, population-based surveillance program for cervical intraepithelial neoplasia grades 2 or higher and adenocarcinoma in situ (AIS; collectively CIN2+). Available archived diagnostic tissue was tested for HPV 16, 18, and other HPV types. We evaluated the average annual percent change (AAPC) in the proportion of cervical precancers with HPV 16 or 18 detected overall and by vaccination status, age group, diagnosis, race/ethnicity, and surveillance site. RESULTS: During 2008-2019, 17,323 CIN2+ cases had valid typing results. The proportion of cases positive for HPV16/18 significantly decreased 3.6% per year. The largest decrease occurred among cases in vaccinated women (AAPC = -8.9), with smaller but still significant decreases among unvaccinated women (AAPC = -2.3). Significant decreases were observed among all subgroups evaluated except women aged 35-39 years, AIS, and Asian women. CONCLUSIONS: During 2008-2019, decreases in the proportion of CIN2+ that were HPV16/18-positive among vaccinated and unvaccinated women, and in most subgroups evaluated, suggest direct and indirect HPV vaccination impact. IMPACT: HPV vaccination impact on precancers is prognostic of future decreases in cervical cancer. Continued monitoring can enable evaluation of vaccination impact in population subgroups.