Safety, Tolerability and Immunogenicity of the Candidate Vaccine MVA-SARS-2-ST Against COVID-19

The vaccine contains a Modified Vaccinia Virus Ankara (MVA) vector expressing a stabilized SARS-CoV-2 spike protein (S). This will be a phase Ib multi-center study in approximately 60 adults aged 18-64 years. Part A (N=24 seronegative subjects). Each participant will receive two single injections, 28 days apart. * low dose ≥ 1 x 10e7 IU (N=8) * middle dose ≥ 5 x 10e7 IU (N=8) * high dose ≥ 1 x 10e8 IU (N=8) Part B (N=36 previously mRNA vaccinated subjects). Each participant will receive a single injection. * low dose ≥ 1 x 10e7 IU (N=12) * middle dose ≥ 5 x 10e7 IU (N=12) * high dose ≥ 1 x 10e8 IU (N=12) All participants will be followed up for safety until D168.