Ko JS, Goldbeck CS, Baughan EB, et al. - In this cross-sectional study, researchers intended to determine if there is a connection between human papillomavirus (HPV) vaccination school-entry requirements and vaccination initiation in jurisdictions with such vaccination policies (ie, Virginia, the District of Columbia, and Rhode Island) vs other regions of the US, as determined by the National Center for Chronic Disease Prevention and Health Promotion. The 2017 cross-sectional study involved 4,784 adolescents aged 13 to 17 years (2,228 [46.6%] girls; 2,556 [53.4%] boys; mean [SD] age, 15.0 [1.4] years; interquartile range, 14-16 years). All policy jurisdictions except Virginia experienced greater differential changes in prepolicy and postpolicy vaccination initiation among girls and boys compared with nonpolicy jurisdictions in the same region. Findings suggested an association of HPV vaccination school-entry requirements with increased vaccination initiation.