An Evaluation of Dose-related HPV Vaccine Effectiveness Using Central Registries in Michigan
Menée à partir de données des registres d'immunisation et des cancers de l'Etat du Michigan portant sur 773 193 femmes, cette étude évalue l'efficacité du vaccin anti papillomavirus humain contre les lésions cervicales intraépithéliales de haut grade (CIN3+) en fonction du nombre de doses de vaccin reçues et selon l'âge au moment de la vaccination
Background: Human papillomavirus (HPV) vaccine effectiveness (VE) evaluations provide important information for vaccination programs. We established a linkage between statewide central registries in Michigan to estimate HPV VE against in situ and invasive cervical lesions (CIN3+). Methods: We linked females in Michigan's immunization and cancer registries using birth records to establish a cohort of 773,193 women with known vaccination history, of whom 3,838 were diagnosed with CIN3+. Residential address histories from a stratified random sample were used to establish a subcohort of 1,374 women without CIN3+ and 2,900 with CIN3+ among continuous Michigan residents. VE and 95% confidence intervals (CI) were estimated using cohort and case-cohort methods for up-to-date (UTD) vaccination and incomplete vaccination with 1 and 2 doses, and stratified by age at vaccination. Results: Both analytic approaches demonstrated lower CIN3+ risk with UTD and non-UTD vaccination vs. no vaccination. The cohort analysis yielded VE estimates of 66% (95% CI 60-71%) for UTD, 33% (95% CI 18-46%) for 2 doses-not UTD, and 40% (95% CI 27-50%) for 1 dose. The case-cohort analysis yielded VE estimates of 72% (95% CI 64-79%) for UTD, 39% (95% CI 10-58%) for 2 doses-not UTD, and 48% (95% CI 25-63%) for 1 dose. VE was higher for vaccination at age <20 than {greater than or equal to}20 years. Conclusions: The statewide registry linkage found significant VE against CIN3+ with incomplete HPV vaccination, and an even higher VE with UTD vaccination. Impact: Future VE evaluations by number of doses for women vaccinated at younger ages may further clarify dose-related effectiveness.