Thresholds of eradication for targeted types of HPV dependent on coverage rates of children and adults. The three-dose curve uses a childhood efficacy of 99% and an adult efficacy of 84.1%. The two-dose curve uses a childhood efficacy of 97% and an adult efficacy of 80.9%. Other parameters are given in Table 2. If no adult vaccination is undertaken, then a childhood vaccination program must cover 90% with three doses and 88% with two doses if the vaccine does not wane. If 80% of children are vaccinated with three doses of a nonwaning vaccine, then the eradication of targeted types can only be achieved if at least 40% of adults are also vaccinated; these requirements become harsher as the number of doses decreases or as the waning of the vaccine increases.