TABLE 2.
Number of Lifetime Cervical Cancer Cases and Cervical Cancer Deaths Among the 26 Million Girls Currently 12 Years and Younger in the United States, and Percent Reduction in Cervical Cancer Cases Compared With No Vaccination, Under Various Coverage Scenarios for a Female-Only HPV Vaccination Program
| Dynamic Model Results | Alternate “Static” Calculations | |||||
|---|---|---|---|---|---|---|
| Vaccination Scenario | No. Cervical Cancer Cases | No. Cervical Cancer Deaths | Percent Reduction in Cervical Cancer vs. no Vaccination (Range) | No. Cervical Cancer Cases | No. Cervical Cancer Deaths | Percent Reduction in Cervical Cancer vs. no Vaccination (Range) |
| No vaccination | 168,400 | 54,100 | N/A | 176,800 | 56,800 | N/A |
| 30% in all years | 122,900 | 39,500 | 27.0 (20.7–32.5) | 141,500 | 45,400 | 20.0 (15.3–24.0) |
| 50% in all years | 98,400 | 31,600 | 41.6 (32.3–9.7) | 118,000 | 37,900 | 33.3 (25.5–40.0) |
| 30% in year 1, then 80% | 74,000 | 23,800 | 56.1 (44.2–66.5) | 87,300 | 28,000 | 50.6 (38.8–60.9) |
| 50% in year 1, then 80% | 72,200 | 23,200 | 57.1 (45.0–67.8) | 85,500 | 27,400 | 51.7 (39.6–62.2) |
| 80% in all years | 69,600 | 22,300 | 58.7 (46.3–69.6) | 82,700 | 26,600 | 53.2 (40.8–64.0) |
The number of cervical cancer cases and deaths are those estimated to occur among the lifetimes of 13 consecutive female birth cohorts (i.e., girls currently 12 years old and younger) in the United States. For simplicity, we focused on vaccination of 12-year-old girls only, thus assuming that coverage rates of 30%, 50%, and 80% could be achieved at age 12 years. We did not include vaccination of older females and males of any age. Cervical cancer screening is included in all vaccine coverage scenarios (including “no vaccination”).
The alternate calculations use simple equations as described in the text to approximate the direct benefits of vaccination and do not include indirect or herd effects. The number of cervical cancer cases in the no-vaccination scenario in the alternate calculations differs from that of the dynamic model because the alternate calculations are based on estimates of the lifetime risk of cervical cancer, whereas the dynamic model applied age-specific annual rates of cervical cancer.
The range of values shown for the percent reduction in cervical cancer (vs. no vaccination) was obtained from the sensitivity analyses when we simultaneously modified our assumptions regarding vaccine efficacy and the percentage of cervical cancer attributable to HPV types 16 and 18, as described in Table 1.