Evaluating Clinical and Cost Impacts of Achieving 90% HPV Vaccination Rate Against Cervical Cancer in Canada Using the OncoSim Cancer Simulation Model

Abstract

Background: Cervical cancer can be largely prevented through vaccination against the human papillomavirus (HPV). In Canada, HPV vaccination of school-aged girls started in 2008 and has reached an average rate of 67% across the country. However, this rate is below a current national target of 90%. Aim: We project the difference in lifetime clinical outcomes and health system costs of achieving a 90% HPV vaccination rate versus a 67% rate for girls vaccinated in 2015 using the OncoSim-Cervical model. Methods: The OncoSim-Cervical model (version 2.5) is a microsimulation model led by the Canadian Partnership Against Cancer, with model development by Statistics Canada, to evaluate the impacts of cervical cancer interventions in Canada. It has two parts, the first, the HPV Microsimulation Model, simulates the transmission of HPV between males and females including possible modulation by vaccination and herd immunity, and provides projections of HPV infection and prevalence for input to the cervical cancer natural history component in the second part. We simulated two cohorts of 5-10 year old girls in 2015; one receiving HPV vaccination at the rate of 67% and another at 90%. Their relative lifetime cervical cancer outcomes and costs were compared. Assumptions included: 100% efficacy of the HPV vaccine; triennial cytology screening between ages 21 and 65; 90% screening recruitment of age-eligible women with 80% rescreening; and a $500 cost for a 3-dose quadrivalent HPV vaccine regimen. Projected costs were undiscounted and are in 2016 CAD. Results: Compared with the 67%-vaccinated cohort, in the 90%-vaccinated cohort there was a lifetime reduction of 23% in cervical cancer incident cases and 21% in cervical cancer deaths. Lifetime cancer treatment costs decreased by $26 million (23%), and wart treatment costs and precervical cancer costs decreased by $3.2 million (15%) and $45 million (16%) respectively. Lifetime screening costs decreased by $47 million (2%). Conclusion: Achieving a nationally-set target of 90% HPV vaccination in Canadian girls would not only save more lives but would free up funds that could be redirected to other health system needs. Planners could aim for relatively high nation-wide rates of HPV vaccination coverage to enhance their cervical cancer control strategy.