The invention discloses a preparation method and an application of a recombinant cold-
adaptation attenuated
influenza vaccine strain. The method comprises the following steps: importing an influenza
virus hemagglutinin HA
gene, an influenza
virus neuraminidase NA
gene as well as seven genes, namely PB2, PB1, PA, NP, M, NS1 and NS2, in an influenza
virus to a host
cell, and conducting cultivating, so that a
recombinant virus is obtained. Tests prove that an attenuated influenza tetravalent vaccine, which is prepared by virtue of a 7+2
plasmid rescuing
system, can achieve an excellent immune effect through nasal immunization; the influenza virus, which is recombined by the 7+2
plasmid rescuing
system, has a property of being time-efficient; in accordance with the epidemic characteristics of influenza viruses in various years, effective targeted influenza vaccines can be prepared; and the preparation method is rapid, obvious in
immunogenicity and
immune protection effect, and good in safety; therefore, the problems on safety and stability of attenuated influenza vaccines which are prepared by virtue of a conventional method are solved, and a protection spectrum of the influenza vaccines is more comprehensive.