CHMP5 and infection: To confirm the immunization efficacy in CAG-hACE2 and other transgenic mice, the RBDs of SARS-CoV-2 spike protein were subcutaneously administrated with AddaVax in the CAG-hACE2 mice on days –35 and –7, followed by intratracheal infection with SARS-CoV-2 at a dose of 2 × 103 TCID50 or 1 × 104 TCID50 (Figure 8A).