Opportunistic HPV vaccination at age 16-23 and cervical screening attendance in Sweden: a national register-based cohort study

Objectives To investigate whether cervical screening attendance differs between human papillomavirus (HPV)-vaccinated and unvaccinated women and to investigate potential underlying socioeconomic factors. Design Prospective cohort using registry linkage of vaccinations, screening invitations, screening attendance and socioeconomic covariates. Setting Swedish national HPV vaccination and cervical screening programmes. Participants All Swedish women born between 1988 and 1991 and invited to screening (n=261 434). Outcome measures All participants were followed for up to 3 years. Screening attendance was compared between HPV-vaccinated and unvaccinated women. HR and 95% CI were estimated using Cox regression. Results Vaccination age averaged 18.1 years and the coverage for=1 dose was 13.5%. In HPV-vaccinated women (n=35 460), screening attendance was higher than in unvaccinated women (n=225 974) (74% vs69%, p<0.001). The crude HR of attendance in HPV-vaccinated women was 1.32 (95% CI 1.30 to 1.34). A positive association remained after adjustment for education, income and migration history (HR=1.10, 95% CI 1.09 to 1.12). Conclusion HPV-vaccinated women were more likely to attend screening than unvaccinated women. Yet, the question needs to be reassessed in routinely vaccinated cohorts, since the vaccinated women included here represent a selected group and may be prone to more health-conscious habits.