Table 2.
Observed Rate Ratios and Vaccine Effectiveness Among Healthcare Workers after COVID-19 Vaccine Second Dose and COVID-19 Infection by RT-PCR, Hospital Israelita Albert Einstein, São Paulo, Brazil, from January 1, 2021, to August 3, 2021
| Variable | RR (95% CI) | P Value | Vaccine Effectiveness (95% CI) |
|---|---|---|---|
| COVID-19 infection | |||
| Unvaccinated | 1.0 (Reference) | ||
| CoronaVac | 0.497 (0.387–0.638) | <.001 | 50.3% (36.2%–61.3%) |
| ChAdOx1 | 0.121 (0.084–0.174) | <.001 | 87.9% (82.6%–91.6%) |
| COVID-19 infection adjusted for covariates | |||
| Unvaccinated | 1.0 (Reference) | ||
| CoronaVac | 0.487 (0.363–0.654) | <.001 | 51.3% (34.6%–63.7%) |
| ChAdOx1 | 0.119 (0.083–0.172) | <.001 | 88.1% (82.8%–91.7%) |
| Sex, male | 0.859 (0.669–1.105) | .237 | |
| Age, y | 0.996 (0.984–1.008) | .540 | |
| HCW job type (direct patient exposure) | 1.020 (0.782–1.331) | .885 | |
Note. RT-PCR, real-time polymerase chain reaction; RR, rate ratio; CI, confidence interval; ChAdOx1, Oxford-AstraZeneca vaccine; HCW, healthcare worker.