Phase II randomized, double-blinded comparison of a single high dose (5 × 108 TCID50) of modified vaccinia Ankara compared to a standard dose (1 × 108 TCID50) in healthy vaccinia-naïve individuals

HD MVA was safe and well-tolerated. While the hazard rate for seroconverting was significantly higher in the HD group before second dose, the effect was small as the median time to seroconversion was identical. When comparing PRNT, non-inferiority of one SD was not established and the peak titers were low for both groups. The HD peak response was inferior to the standard two-dose regimen response based on ELISA and PRNT.