Sample size and power calculations for a registry-based follow-up study on the efficacy of human papillomavirus (HPV) type 16/18 vaccine against cervical intraepithelial neoplasia grade three and invasive cancer (CIN3+). (A) Required sample sizes for the cancer-registry follow-up phase III trial cohorts assuming 90% vaccine efficacy against CIN3+ (statistical power: 1-β=80%, α=0.05) and 10 years of follow-up. (B) Statistical power with actuarial*† sample sizes for the cancer-registry follow-up of phase III trial cohorts assuming 50%, 70% and 90% HPV vaccine efficacy (VE) against CIN3+
Cumulative incidence % | Category | Design 1:3 | Design 1:4 | |
0.2 | HPV vaccinated/unvaccinated | 3 990/11 970 | 3 880/15 520 | |
0.4 | HPV vaccinated/unvaccinated | 1 773/5 319 | 1 685/6 740 | |
0.6 | HPV vaccinated/unvaccinated | 936/2 808 | 889/3 556 | |
0.8 | HPV vaccinated/unvaccinated | 795/2 385 | 755/3 220 | |
1.2 | HPV vaccinated/unvaccinated | 495/1 485 | 470/1 880 |