Receiving at least one dose of quadrivalent HPV vaccine prior to age 18 years significantly lowered the incidence of abnormal cervical cytology or histology in a retrospective cohort of 104,313 women born between 1990–1994. All had cervical cytology or histology recorded when aged 20–24. Vaccinated women had a 25% lower incidence of high-grade cytology (8.5 vs 11.3 per 1000 person years; p<0.001) and a 31% lower incidence of high-grade histology (6.0 vs 8.7 per 1000 person years; p<0.001) than unvaccinated women. No differences were evident between New Zealand European and Māori women in the incidence of high-grade cytology irrespective of vaccination status.
