The present invention relates to the rapid induction of a protective immune response against poxvirus infections such as smallpox by vaccination of an animal, including a human with a poxvirus that is replication incompetent in said animal including the human. An example for such a poxvirus as a Modified Vaccinia virus Ankara (MVA). The invention further relates to the use of a recombinant poxvirus that is replication incompetent in the animal, including the human that is vaccinated with the virus,such as a rembinant MVA expressing heterologous antigens and/or antigenic epitopes for a rapid induction of a protective immune responses against said heterologous antigen and/or antigenic epitope, e.g. against an antigen and/or antigenic epitope that is part of an infectious agent.
