Figure 2. Impact of vaccine effectiveness and coverage level on reduction in lifetime risk of cancer in Kenya.

Colored vertical bars represent the mean reduction in cancer risk (on the y-axis) at different levels of overall vaccine effectiveness (60-100%, on the x-axis) for varying levels of vaccination coverage (i.e., proportion of the target population that receives at least one dose of vaccine) (blue, 25%; purple, 50%; pink, 75%). Error bars represent the range of uncertainty in cancer reduction based on the 50 top-fitting parameter sets. Overall vaccine effectiveness is a function of per-dose efficacy and the attrition rate following each dose (e.g., for an attrition rate of 40%: of the girls who received at least one dose, 40% received only the first dose, 24% received two doses, and 36% received three doses). For example, an overall vaccine effectiveness of approximately 60% would be realized with a vaccine conferring 100% efficacy with administration of 3 doses, 50% for 2 doses, and no benefit for 1 dose, and an attrition rate of 40% between each dose. The table at the top of the graph describes scenarios that yield costs, benefits, and reduction in cancer risk similar to each corresponding level of overall effectiveness shown.