Currently, the steps performed prior to release of influenza strains to vaccinemanufacturers involve passaging influenza virus through eggs. The inventionaims to provide procedures useful in manufacturing influenza vaccines, in whichthe use of eggs is reduced, and preferably is avoided altogether. For instance,rather than use chicken eggs for influenza vaccine isolation, MDCK cells (MadinDarby canine kidney cells) may be used e.g. growing in suspension, growing ina serum-free medium, growing in a protein-free medium, being non-tumorigenic,grown in the absence of an overlay medium, etc.
