This is a phase Ⅱ, single-center, randomized, double-blind, placebo-controlled study, to evaluate the immunogenicity and safety of the recombinant COVID-19 vaccine (Sf9 cells) in the subjects from healthy adults and elderly adults aged 18 years and above (aged 18-60 and 60-85 years) . The phase Ⅱ clinical trials designed 8 research group, including two immunization procedures (0, 21 days and 0, 14, 28 days), two doses (20μg/0.5ml, 40μg/1.0ml) and two ages group (adults and elder): Each group including 120 participants. Vaccination or placebo group will be randomly assigned to receive in a 5:1 ratio, 960 in total.
This is a phase Ⅱ, single-center, randomized, double-blind, placebo-controlled study, to evaluate the immunogenicity and safety of the recombinant COVID-19 vaccine (Sf9 cells) in the subjects from healthy adults and elderly adults aged 18 years and above (aged 18-60 and 60-85 years) with different immunization procedures (0, 21 days and 0, 14, 28 days) and doses (20μg/40μg).