Table 6.
Estimation of Constant Vaccine Efficacy With Unknown Change Points Under No Crossover (A), Blinded Priority-Dependent (B) and Priority-Independent (C) Crossover, and Unblinded Priority-Dependent (B’) and Priority-Independent (C’) Crossover When VEh Stays at 80% After the Change Point
| True Change Point = 4 Weeks | True Change Point = 6 Weeks | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Design | Mean (%) | SE (%) | SEE (%) | CP (%) | Correct (%) | Mean (%) | SE (%) | SEE (%) | CP (%) | Correct (%) |
| A | 79.9 | 1.50 | 1.47 | 94 | 73 | 79.9 | 1.46 | 1.47 | 94 | 65 |
| B | 80.0 | 1.42 | 1.42 | 95 | 80 | 79.9 | 1.43 | 1.42 | 95 | 73 |
| C | 79.9 | 1.78 | 1.70 | 94 | 82 | 79.9 | 1.73 | 1.69 | 95 | 78 |
| B’ | 79.9 | 1.58 | 1.52 | 94 | 72 | 79.9 | 1.60 | 1.53 | 94 | 67 |
| C’ | 79.9 | 1.96 | 1.90 | 94 | 70 | 79.9 | 1.91 | 1.91 | 95 | 67 |
Mean and SE denote the mean and standard error of the vaccine efficacy (VE) estimator, SEE denotes the mean of the standard error estimator, and CP denotes the coverage probability of the 95% confidence interval. Correct denotes the probability of correctly selecting the change point by the Akaike information criterion.
Abbreviation: VEh, vaccine efficacy on hazard rate.