are double stranded dna viruses in one embodiment the viruses are influenza viruses in another embodiment the viruses are coronavirus viruses e g sars cov in one embodiment the protein or nucleic acid sequences are from influenza viruses in one embodiment the influenza nucleic acid or polypeptide sequences are selected from the group consisting of ha na np pa pb1 pb2 mp and ns or combinations thereof in one embodiment the nucleic acid or polypeptide sequences are obtained by sequencing the isolated viral strains in another embodiment the sequences are obtained by sequencing nucleic acid molecules isolated from a subject e g a human or animal or a tissue sample in another embodiment the nucleic acid or polypeptide sequences are obtained from a publicly available database in certain embodiments the sufficient number is 5 10 20 30 40 50 or more viral sequences in one embodiment the one or more viral genes is at least two three four or five or more genes in another aspect the invention provides a method of producing a viral vaccine comprising infecting a host animal host animal cell cell line egg cell bacterial cell or cell extract which supports viral replication with the parental viral strains identified according to the methods described above and isolating mutant progeny viral strains from the host animal cell line egg cell bacterial cell or cell extract which supports viral replication viral vaccines of the present invention can be for example live vaccines killed vaccines attenuated vaccines or subunit vaccines see for example fields.