Safety, and Immunogenicity Study of the Recombinant Two-component COVID-19 Vaccine (CHO Cell)

Part 1: Primary Vaccination in Adults Part 1 will evaluate the safety and immunogenicity of the recombinant two component COVID-19 vaccine (CHO cell) (ReCOV for short) in adults aged 18 years and older, when administered as 2 intramuscular doses, 21 days apart. Part 2: Booster Vaccination in Adults Part 2 will evaluate the immunogenicity and safety and of one booster dose of ReCOV in adult participants who have received primary vaccination with 2 doses of an inactivated COVID-19 vaccine (CoronaVac®). COMIRNATY®, an mRNA COVID-19 vaccine will be used as the active control.