The present invention discloses a recombinant bacteriophage comprising a phage genome polynucleotide including a gene encoding a heterologous antigen protein(s) and a killing gene encoding a protein that is capable of killing a host bacterium. Such a recombinant bacteriophage is designed to prime a subjects immune response and to kill the bacterium that it infects such that the "prime and kill" bacteriophage provides two lines of protection against infectious disease.
