Effect of grade and dose. values based on the grade of vaccination and the number of doses. Panel (a) represents the effects of two doses and panel (b) represents three doses. The grade of vaccination is controlled by forcing except for the given grade. The number of doses is defined by different ranges of and . The horizontal line represents the threshold for eradication, . For a childhood-only program, the median is close to 1 (i.e., HPV types 6, 11, 16, and 18 are candidates for eradication), independent of the number of doses given. This contrasts with an adult-only vaccination program, where the median is always above 1 (i.e., the disease will persist). All other parameters used the ranges in Table 2.