ABSTRACT
Background: Various types of vaccines against SARS-CoV-2 have reduced the burden of coronavirus diseases 2019 (COVID-19) across the world. We conducted an observational study to evaluate the effectiveness of NVX-CoV2373 and BNT162b2 in providing protection in Korean adults. Methods: This study was a retrospective matched cohort study to emulate a target trial of three doses of NVX-CoV2373 (N-N-N) versus three doses of BNT162b2 (B-B-B) vaccines in presumed immune-naive adults. We used data from the Korea COVID-19 Vaccine Effectiveness (K-COVE) cohort, combining all COVID-19 laboratory-confirmed cases and all COVID-19 immunization registry, between February and November 2022. We calculated 40-week risk differences and risk ratios between the two vaccines. Results: A total of 3,019 recipients of NVX-CoV2373 vaccine and 3,027 recipients of BNT162b2 vaccine were eligible for the study. The 40-week risk ratios for recipients of the NVX-CoV2373 vaccine as compared with recipients of the BNT162b2 vaccine were 1.169 (95% CI, 1.015 to 1.347) for laboratory-confirmed SARS-CoV-2 infection, and 0.504 (95% CI, 0.126 to 2.014) for severe SARS-CoV-2 infection. Estimated risk of severe infection was 0.001 events per 1000 persons (95% CI, 0 to 0.003) for the NVX-CoV2373 vaccine and 0.002 events per 1000 persons (95% CI, 0.001 to 0.006) for BNT162b2 vaccine. Conclusion: This study identifies reduced risk of SARS-CoV-2 infection and severe infection after receipt of three doses of either NVX-CoV2373 or BNT162b2 vaccines in Korean adults. Direct, vaccine-conferred protection may be of importance among high risk persons to mitigate from serious clinical outcome from COVID-19.