Material and methods for the production of an improved vaccine against influenza vrs which comprises a reassortant virus havn a hemaggiutinin gene and a neuraminidase gene from the same inluenza A virus subtype or oflkuenza B strain of virus and intmera genes from a different influenza A virus subtype orinfluenza B strn of virus Vrone aspecthe HA and NA genes and thegntemal genes are from a highy pathogenic H5NI strain of influenza A
