New vaccine production could improve flu shot accuracy

For decades, vaccine manufacturers have used chicken eggs to grow the flu virus strains included in the seasonal vaccine. But because these human strains frequently mutate to adapt to their new environment, the resulting vaccine is often an imperfect match to the virus that it is supposed to protect against. Researchers have now devised a way to keep the human influenza virus from mutating during egg-based production, generating a perfect match to the target vaccine.