The invention relates, in general, to synthetic chimeric poxviruses, compositions comprising such viruses, and the development and use of systems and methods for producing such synthetic chimeric poxviruses. The synthetic chimeric poxviruses are well suited for live virus vaccines and pharmaceutical formulations.

Described herein are compositions including a nucleic acid sequence (e.g., mRNA) encoding an infection agent antigenic polypeptide and a nucleic acid sequence (e.g., mRNA) encoding at least one universal T-cell epitope (UTE), as well as compositions including a nucleic acid sequence (e.g., mRNA) encoding an infection agent antigenic polypeptide and at least one universal T-cell epitope, and methods for using the compositions.

The invention relates, in general, to synthetic chimeric poxviruses, compositions comprising such viruses, and the development and use of systems and methods for producing such synthetic chimeric poxviruses. The synthetic chimeric poxviruses are well suited for live virus vaccines and pharmaceutical formulations.