Table 3 Power available for various aggregate seroconversion rates and effect sizes. Note: The interim seroconversion rate in the control arm was derived algebraically from the observed aggregate rate and the effect size
Interim aggregate seroconversion rate (threshold for stopping) | 50% effect size | 40% effect size | 30% effect size | |||
|---|---|---|---|---|---|---|
Interim seroconversion rate in control arm | Power | Interim seroconversion rate in control arm | Power | Interim seroconversion rate in control arm | Power | |
10% | 13% | 81% | 12% | 56% | 12% | 32% |
15% | 20% | 95% | 19% | 76% | 18% | 47% |
20% | 27% | 99% | 25% | 89% | 24% | 61% |
25% | 33% | > 99% | 31% | 96% | 29% | 74% |
30% | 40% | > 99% | 37% | 99% | 35% | 84% |
33% | 44% | > 99% | 41% | 99% | 39% | 88% |
34% | 45% | > 99% | 42% | 99% | 40% | 90% |
35% | 47% | > 99% | 44% | > 99% | 41% | 91% |
40% | 53% | > 99% | 50% | > 99% | 47% | 96% |