Cleveland AA, et al. - Researchers assessed the epidemiology of adenocarcinoma in situ (AIS), a rare cervical precancer, using population-based surveillance to identify AIS and cervical intraepithelial neoplasia (CIN) grade 3 (CIN3) cases. They also examined data on human papillomavirus (HPV) types and incidence patterns overall and among women screened for cervical cancer. They identified 470 and 6,587 cases of AIS and CIN3, respectively, from 2008 to 2015. In both AIS and CIN3, the most frequently detected type was HPV16. The probability of a positive result for high-risk types of HPV targeted by the bivalent and quadrivalent vaccines and 9-valent vaccine, was higher for AIS lesions vs CIN3 lesions. A crucial opportunity for vaccine prevention of AIS was indicated in this study that included the largest number of genotyped AIS cases to date. During the vaccine era, a reduction in AIS incidence rates in young women was reported for the first time in this study.