New flu virus

Influenza virus that lacks proteins NS1 and PB1-F2 functional and that is deficient in replication-competent cells interferon, wherein the ORF PB1-F2 is modified by the introduction of at least one stop codon by modifying either T120, T153, T222, T234, T255, T270 and G291 according to the numbering of SEQ ID NO: 1 and which has been removed the NS1 protein positions.