Cervical screening rates for women vaccinated against human papillomavirus.

OBJECTIVE To compare cervical screening rates for women vaccinated with a quadrivalent human papillomavirus (HPV) vaccine with those for unvaccinated women, to address concerns that vaccinated women may not be participating in cervical screening. DESIGN, SETTING AND PARTICIPANTS Cross-sectional analysis of linked data from the Victorian Cervical Cytology Registry and the National HPV Vaccination Program Register for 20-29-year-old women in Victoria, Australia, for the period 1 January 2009 to 31 December 2011. MAIN OUTCOME MEASURES Screening participation rates for vaccinated and unvaccinated women. RESULTS Participation in cervical screening during the 2-year period 2010-2011 was significantly lower in 20-24-year-old vaccinated women compared with unvaccinated women of the same age (37.6% v 47.7%, a 10.1 percentage point difference [95% CI, 9.7-10.6]; P < 0.001) and significantly lower in 25-29-year-old vaccinated women compared with unvaccinated women of the same age (45.2% v 58.7%, a 13.5 percentage point difference [95% CI, 13.1%-13.9%]; P < 0.001). Similar results were observed for participation during the 3-year period 2009-2011. CONCLUSIONS Despite education messages provided to young women, our results suggest that vaccinated women are being screened at lower rates than unvaccinated women in Australia. While some degree of undermatching of women in the study may have occurred, this cannot wholly explain our findings. Effective implementation of Individual Healthcare Identifiers to health records, including registry records, is needed to prevent potential undermatching of individuals in future linkage studies. In the meantime, efforts to increase participation in cervical screening by vaccinated women are needed.