Table 2.
Examples of total sample sizes required for field studies of second-generation vaccine to demonstrate non-inferiority or superiority (reported in 1,000s; assuming intention-to-treat)
| Power (1-β) | : 80% | ||
|---|---|---|---|
| Two-sided significance level (α) |
: 5% |
||
| Control vaccine efficacy |
: 50% |
||
| Follow-up time |
: 2 years |
||
| Incidence rate in those not vaccinated |
: 1/10 PYs |
||
|
New vaccine efficacy (%) |
Superiority |
Non-inferiority margin |
|
| |
|
5% |
10% |
| 50 |
--- |
28.7 |
7.3 |
| 55 |
27.4 |
7.0 |
3.2 |
| 60 |
6.6 |
3.0 |
1.7 |
| 65 | 2.9 | 1.6 | 1.1 |
Sample sizes are reported in 000’s and calculated using Z-test with continuity correction.