Examining Provincial HPV Vaccination Schemes in Canada: Should We Standardise the Grade of Vaccination or the Number of Doses?

Figure 1

The model. Movement of individuals through childhood vaccination programs and the infection cycle as adults. Girls from grades 4 to 10 (pink, ) can be vaccinated (shaded) depending on the proportion vaccinated () and the efficacy of the vaccine (). Once the girls turn 16 (approximately grade 11), they enter adulthood (purple) where they may become infected (dashed) with HPV. Unvaccinated women () can become vaccinated () or become infected () with transmission rate when they meet an infected man (). Vaccinated adult women () can also become infected () but with a reduced transmission rate, due to the failure of the vaccine (). Unvaccinated men () become infected upon contact with infected women, with transmission rate . The vaccine wanes at rate , while protection is lost at rates . The mortality rate for children is and the leaving rate of adults is . The parameters measure the degree of preexisting infection in children.