Table 3.
Estimates of vaccine effectiveness against symptomatic infection
| Time period | mRNA-1273 or BNT162b2 (days 1–10 after first dose) | mRNA-1273 (fully vaccinated) | BNT162b2 (fully vaccinated) | |
|---|---|---|---|---|
| Study duration Dec 1, 2020–Sept 22, 2021 | cases | 607 | 861 | 2,526 |
| controls | 2,135 | 11,796 | 24,199 | |
| vaccine effectiveness (95% CI) | 84.1% (81.6%, 86.2%) | 75.6% (72.2%, 78.7%) | ||
| Early epoch Dec 1, 2020–May 31, 2021 | cases | 487 | 28 | 128 |
| controls | 1,887 | 2,137 | 4,948 | |
| vaccine effectiveness (95% CI) | 93.7% (90.4%, 95.9%) | 85.7% (81.4%, 88.9%) | ||
| Late epoch Jul 1, 2021–Sept 22, 2021 | cases | 119 | 814 | 2,349 |
| controls | 234 | 8,772 | 17,637 | |
| vaccine effectiveness (95% CI) | 75.6% (70.1%, 80%) | 63.5% (55.8%, 69.9%) |
For each time period, conditional logistic regression was used to calculate odds ratios of symptomatic infection after full vaccination versus during the 10 days after the first dose, adjusted for demographic and clinical covariates. Vaccine effectiveness was calculated as 100% × (1 − adjusted odds ratio).