Effectiveness of Heterologous COVID-19 Vaccine Booster in Korean Elderly Population, 2022

ABSTRACT

We conducted a cohort study to assess vaccine effectiveness (VE) of coronavirus disease 2019 vaccine combinations on severe acute respirator y syndrome coronavirus 2 critical infection and death among elderly population in Korea. From Januar y to August 2022, VE against death for 4 doses mRNA recipients was 96.1%, whereas 1-dose viral vector + 3-dose mRNA recipients had VE of 90.8%.