This is a randomized, open-labeled, Phase IIb clinical trial of 300 participants aged 18 years and above, who have completed two or three doses of mRNA vaccine or CoronaVac® in Hong Kong for at least 90 days after the last dose. After enrollment, the participants will be assigned to 2 groups according to their previous vaccination (mRNA vaccine group and CoronaVac® group) and then each group will be randomly assigned to two study arms at a ratio of 1:1 to receive one or two booster doses of COVID-19 Vaccine (Vero Cell), Inactivated, Omicron Strain.
This is a randomized, open-labeled, Phase IIb clinical trial.The purpose of this study is to evaluate the immunogenicity and safety of the booster vaccine of using one or two doses of COVID-19 Vaccine (Vero Cell), Inactivated, Omicron Strain in Adults above 18 Years Old Who Have Completed Two or Three Doses of mRNA Vaccine or CoronaVac®.