| abstract |
The present invention provides a composition useful for the preparation of high-titer influenza B viruses (for example in the absence of helper virus), said composition comprising internal genes from influenza B virus vaccine strains or isolates, said Influenza B virus vaccine strains or isolates, e.g., those that are safe in humans, e.g., do not cause significant disease, confer increased growth in cultured cells (e.g. MDCK cells) or in eggs Influenza B virus vaccine strain or isolate. |