GROUP OF ATTENUATED STRAINS OF INFLUENZA A VIRUS BASED ON SYNONYMOUS MUTATION AND/OR DELETION MUTATION, AND PREPARATION METHOD THEREFOR AND USE THEREOF

Provided are a group of attenuated strains of the influenza A virus based on synonymous mutation and/or deletion mutation, and a preparation method therefor and the use thereof. The attenuated strains are obtained by modifying an M2 gene; the modification comprises performing synonymous mutation on an overlapping part of the M2 gene and an M1 gene in an M gene of the influenza A virus to ensure that the amino acid sequence of M1 is complete and unchanged; or the modification comprises performing synonymous mutation on the overlapping part of the M2 gene and the M1 gene in the M gene of the influenza A virus to ensure that the amino acid sequence of M1 is complete and unchanged, and deleting some nucleotide sequences from the M2 gene. The attenuated strains have strong stability, do not undergo reverse mutation after multiple instances of subculturing, have high safety, do not have a strong dependence on a cell line, and have relatively high advantages in a vaccine production process. La présente invention con