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+