TABLE 1.

Selected Assumptions in Dynamic Model

Assumption	Value Applied (Range)
Vaccine efficacy against HPV 16 and HPV 18	95% (85%−100%)
Vaccine duration of protection	Lifelong
Percent of cervical cancer attributable to HPV 16, HPV 18	70% (60%−80%)
Annual probability of acquiring HPV 16, HPV 18	Varied by age
Number of girls currently aged ≤12 y in the United States*	26 million

A complete description of the model, including a list of all parameter values and sources, is provided elsewhere.³ Each of the 13 birth cohorts in the model (those aged 0–12 years) consisted of 2 million girls, for a total of 26 million. This overall population size is consistent with 2012 US Census Bureau estimate of 25.9 million girls aged 0 to 12 years.²⁰ The annual probability of acquiring HPV 16 and HPV 18 varied by age and was adjusted from year to year according to decreases in HPV 16 and HPV 18 in the population.

We assumed the vaccine would have no impact on the cervical cancers not attributable to HPV 16 or HPV 18, and thus, we made no assumptions about the percent of cervical cancers attributable to other HPV types.

^*We estimated the number of cervical cancer cases (and deaths) expected to occur over the lifetimes of girls currently 12 years and younger in the United States, under various scenarios of HPV vaccine coverage.