Dose-related Effectiveness of Quadrivalent Human Papillomavirus Vaccine Against Cervical Intraepithelial Neoplasia: A Danish Nationwide Cohort Study. (20th March 2019)

• Record Type: Journal Article
• Authors: Verdoodt, Freija; Dehlendorff, Christian; Kjaer, Susanne K
• Is Part Of: Clinical infectious diseases. Volume 70:Number 4(2020)
• Page Start: 608
• Page End: 614
• Publication Date: 2019-03-20
• Subjects: human papillomavirus -- HPV vaccination -- cervical dysplasia -- vaccine effectiveness -- reduced dosing schedule; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciz239
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract: Background: A reduced, 2-dose schedule of human papillomavirus (HPV) vaccination has been endorsed for preadolescent women on the basis of immunogenicity data from randomized trials, and limited data suggest that even 1 dose may provide sufficient protection. Surveillance of the impact of <3 vaccine doses on clinical endpoints in the targeted age group is warranted. Methods: We conducted a nationwide cohort study of all women aged 17–25 years, living in Denmark between 2006 and 2016. From nationwide registries, we extracted individual-level data on vaccination with the quadrivalent HPV (qHPV) vaccine at 16 years or younger, number of doses administered, diagnoses of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) or grade 3 or worse (CIN3+), and potential confounders. Using Poisson regression, we estimated incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for CIN2+ and CIN3+, according to vaccination status. Results: The cohort comprised 590 083 women, of which 215 309 (36%) women were vaccinated at ≤16 years, and among these, 40 742 (19%) received <3 vaccine doses. A total of 5561 women had a diagnosis of CIN3+. We found considerable vaccine effectiveness against CIN3+ after 1 (IRR, 0.38 [95% CI, .14–.98]), 2 (IRR, 0.38 [95% CI, .22–.66]), or 3 (IRR, 0.37 [95% CI, .30–.45]) vaccine doses, compared to unvaccinated women. Results were similar for CIN2+. Conclusions: We find substantial effectiveness of qHPV vaccination against high-grade cervical precancerous lesions, among women vaccinated with 1, 2, or 3 doses at ≤16 years of age. One-dose vaccination appeared to provide similar protection as 3-dose vaccination. Abstract : In a population-based cohort study among young women in Denmark, administration of 1 dose and 2 doses of the qHPV vaccine at age ≤16 years provides similarly high protection against high-grade cervical precancerous lesions, compared to 3 vaccine doses.