Table 1

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 %CategoryDesign 1:3Design 1:4
0.2HPV vaccinated/unvaccinated3 990/11 9703 880/15 520
0.4HPV vaccinated/unvaccinated1 773/5 3191 685/6 740
0.6HPV vaccinated/unvaccinated936/2 808889/3 556
0.8HPV vaccinated/unvaccinated795/2 385755/3 220
1.2HPV vaccinated/unvaccinated495/1 485470/1 880