Verdoodt F, et al. - Immunogenicity data from randomized trials support a reduced, 2-dose schedule of human papillomavirus (HPV) vaccination for preadolescent women, there were, however, limited data suggesting the protection afforded by 1 dose. Researchers here sought to determine the impact of < 3 vaccine doses on clinical endpoints in the targeted age group. In this nationwide cohort study, they obtained individual-level data on vaccination with the quadrivalent HPV (qHPV) vaccine from all women aged 17–25 years, living in Denmark between 2006 and 2016 from nationwide registries. The cohort included 590,083 women. Among these, vaccination at ≤ 16 years was reported in 215,309 (36%) women and of these, 40,742 (19%) received < 3 vaccine doses. Findings support qHPV vaccination as substantially effective against high-grade cervical precancerous lesions, among women vaccinated with 1, 2, or 3 doses at ≤ 16 years of age. They identified one-dose vaccination as effective as 3-dose vaccination.