mRNA Booster Vaccine(SW-BIC-213) Compared With Pfizer andSinopharm Against Emerging VOCs

Primary#Objectives #Immunogenicity:To demonstrate the non-inferiority of binding antibody response in terms of geometric mean titers (GMT) of mRNA vaccine compare with mRNA COVID-19 vaccine(Pfizer) 14 days post dose. Secondary#Immunogenicity: 1. To describe binding antibody profile at D01, D29 and D181 of each study group. 2. To describe the neutralizing antibody profile at D15, D29 and D181 of each study intervention group. Secondary#Safety: To assess the reactogenicity and safety of a booster dose in a heterologous vaccination regimen in subjects previously immunized with two Sinopharm doses. Exploratory#Cell-mediated immunity: To describe the cellular immune response profile at D01, D08, D15, in a subset of 30 participants for each study group. Exploratory#Efficacy: To describe theoccurrence ofvirologically-confirmedCOVID-19 like illness and serologicallyconfirmed SARS-CoV-2 infection.