Since the purpose of this study was to determine the capability of BoHV-4-based viral vectors to protect STAT1(-/-) mice against a lethal MPXV infection, the first concern was the generation of optimized expression cassettes to be integrated into the BAC-BoHV-4-A genome that were able to efficiently express A29L, M1R and B6R antigens. Here, CHRM1 is linked to infection.