Comparative effectiveness and safety of BNT162b2 and CoronaVac in Hong Kong: A target trial emulation

Abstract

ObjectivesTo evaluate the difference between BNT162b2 and CoronaVac in vaccine effectiveness and safety. MethodsThis target trial emulation study included individuals aged ≥12 during 2022. Propensity score matching was applied to ensure group balance. The Cox proportional hazard model was used to compare the effectiveness outcomes including COVID-19 infection, severity, 28-day hospitalization, and 28-day mortality after infection. Poisson regression was used for safety outcomes including 32 adverse events of special interests between groups. ResultsA total of 639,818 and 1804,388 individuals were identified for the 2-dose and 3-dose comparison, respectively. In 2-dose and 3-dose comparison, the hazard ratios (95% confidence intervals [CI]) were 0.844 [0.833-0.856] and 0.749 [0.743-0.755] for COVID-19 infection, 0.692 [0.656-0.731] and 0.582 [0.559-0.605] for hospitalization, 0.566 [0.417-0.769] and 0.590 [0.458-0.76] for severe COVID-19, and 0.563 [0.456-0.697] and 0.457 [0.372-0.561] for mortality for BNT162b2 recipients versus CoronaVac recipients, respectively. Regarding safety, 2-dose BNT162b2 recipients had a significantly higher incidence of myocarditis (incidence rate ratio [IRR] [95% CI]: 8.999 [1.14-71.017]) versus CoronaVac recipients, but the difference was insignificant in 3-dose comparison (IRR [95% CI]: 2.000 [0.500-7.996]). ConclusionBNT162b2 has higher effectiveness among individuals aged ≥12 against COVID-19-related outcomes for SARS-CoV-2 omicron compared to CoronaVac, with almost 50% lower mortality risk.