Cervical Intraepithelial Neoplasia Rates in British Columbia Women: A Population-Level Data Linkage Evaluation of the School-Based HPV Immunization Program

C. Sarai Racey, Arianne Albert, Robine Donken, Laurie Smith, John J. Spinelli, Heather Pedersen, Pamela de Bruin, Cindy Masaro, Sheona Mitchell-Foster, Manish Sadarangani, Meena Dawar, Mel Krajden, Monika Naus, Dirk van Niekerk, Gina Ogilvie

Research output: Contribution to JournalArticleAcademicpeer-review

15 Citations (Scopus)


BACKGROUND: To understand real-world human papillomavirus (HPV) vaccine impact, continuous evaluation using population-based data is critical. We evaluated the early impact of the school-based HPV immunization program on cervical dysplasia in women in British Columbia, Canada. METHODS: Data linkage was performed using records from provincial cervical screening and immunization registries. Precancerous outcomes were compared between unvaccinated and HPV-vaccinated women born 1994-2005. Incidence rate, relative rate (RR), and vaccine effectiveness (VE), using unadjusted and adjusted Poisson regression of cytology (HSIL) and histopathology (CIN2, CIN3, and CIN2+) outcomes, were compared across vaccination status groups. RESULTS: Women who received a complete series of vaccine on schedule between age 9 and 14 years had an adjusted RR = 0.42 (95% confidence interval [CI], 0.31-0.57) for CIN2+ over 7 years of follow-up compared to unvaccinated women, resulting in a VE of 57.9% (95% CI, 43.2%-69.0%). Adjusted RR for HSIL was 0.53 (95% CI, .43-.64), resulting in a VE of 47.1% (95% CI, 35.6%-56.7%). CONCLUSION: Women vaccinated against HPV have a lower incidence of cervical dysplasia compared to unvaccinated women. Immunization between 9 and 14 years of age should be encouraged. Continued program evaluation is important for measuring long-term population impact.

Original languageEnglish
Pages (from-to)81-90
Number of pages10
JournalThe Journal of Infectious Diseases
Issue number1
Publication statusPublished - 1 Jan 2020


  • cervical intraepithelial neoplasia
  • human papillomavirus
  • immunization programs
  • papillomavirus vaccines
  • vaccine effectiveness

Cite this