Comparison with previous studies
To date, results from their respective phase III clinical trials demonstrated that the BNT162b2 vaccine had a 95% efficacy in protecting against COVID-19, while the ChAdOx1 vaccine had a 70% efficacy against COVID-19. Consistent with the findings of clinical trials, results from several observational studies also indirectly showed a slightly higher effectiveness of the BNT162b2 vaccine than the ChAdOx1 vaccine when compared with unvaccinated individuals [