Phase I/II Study of COVID-19 DNA Vaccine (AG0302-COVID19 High-dose)

This is a Phase I/II, multi-center, randomized, open-label, uncontrolled trial. Approximately 400 healthy volunteers, male or female, aged 18 years or older, will be randomized to one of the following five groups: \[IM Groups\] Group A: Vaccination 2 mg, three times at 2-week intervals (n = 80) Group B: Vaccination 4 mg, twice at 4-week intervals (n = 80) Group C: Vaccination 8 mg, twice at 4-week intervals(n = 80) \[ID Groups\] Group D: Vaccination 1 mg, three times at 2-week intervals (n = 80) Group E: Vaccination 1 mg, twice at 4-week intervals (n = 80)