INFLUENZA VACCINES

摘要

A recombinant influenza virus strain derived from (a) an over-attenuated influenza A strain which has been passaged solely in chicken egg cultures, manifests a relatively high yield of virus in such cultures and has an increased capacity for plaque formation on calf kidney cells and (b) a virulent influenza A strain which manifests a relatively low culture yield of virus and is substantially free from contaminating mammalian viruses; a method of manufacturing the recombinant strain and a vaccine incorporating it.