Described herein are chimeric influenza virus gene segments and nucleic acid sequences encoding such chimeric influenza virus gene segments. A chimeric influenza virus gene segment described herein comprises packaging signals found in the non-coding and coding regions of one type of influenza virus gene segment and an open reading frame of a different type of influenza virus gene segment or fragment thereof. Also described herein are recombinant influenza viruses comprising two or more chimeric influenza virus gene segments and the use of such viruses in the prevention and/or treatment of influenza virus disease.
