Cleveland AA, et al. - In view of the observation that both cervical intraepithelial neoplasia (CIN) and adenocarcinoma in situ (AIS) could be affected by performing primary prevention through the use of human papillomavirus (HPV) vaccination, researchers performed population-based surveillance to identify AIS and CIN grade 3 (CIN3) cases, and analyzed data on HPV types and incidence trends overall, and among women screened for cervical cancer. They identified 470 AIS and 6,587 CIN3 cases from 2008–2015. In both AIS and CIN3, the most frequently detected type was HPV16; HPV18 was identified to be the second most common type in AIS however it was less common in CIN3. For high-risk types targeted by the bivalent and quadrivalent vaccines (HPV16/18, 92% vs 63%), and nonavalent vaccine (HPV16/18/31/33/45/52/58, 95% vs 87%), AIS lesions vs CIN3 lesions were more frequently positive. Observation revealed significantly decreased AIS incidence rates in the 21-24 year age group, but no significant decrease in any older age group. They suggest that this study reports on the largest number of genotyped AIS cases to date and is the first to document a decline in AIS incidence rates among young women during the vaccine era. Findings indicate an important opportunity for vaccine prevention of AIS.