In April, the European Medicines Agency published a draft guideline on "Quality Aspects on the Isolation of Candidate Influenza Vaccine Viruses in Cell Culture". This guideline describes quality recommendations for cells used to isolate candidate influenza vaccine viruses, the conditions under which the viruses are isolated and the subsequent passage of the viruses until the manufacturer’s seed is prepared under GMP conditions.
Manufacturers of cell-derived vaccine typically use the recommended egg-derived candidate vaccine virus to derive their seed virus. Research indicates, that there are phenotypic changes of human influenza virus when they are adapted to grow in eggs. It can't be ruled out, that this might include changes in antigenicity or immunogenicity. Viruses isolated from mammalian cell cultures do not appear to undergo these changes. Thus a cell-isolated virus may be more clinically relevant for vaccine than an egg isolate. Many vaccine manufacturers wish by those reasons, to use non-egg adapted viruses which are antigenically closer to the wild type virus. The available cells in use by National Influenza Centres and WHO Collaborating Centres for virus isolation are not qualified/validated for use in deriving a candidate vaccine virus and so currently only egg-isolated viruses are taken forward as vaccine candidates.
Therefore, this document provides essential guidance to influenza vaccine manufacturers and to WHO Collaborating Centres on the quality issues associated with isolating candidate vaccine viruses in cell culture, including the cells used to isolate the virus, the conditions of isolation and the following transfer of these viruses until the manufacturer’s seed is prepared under GMP conditions.
More information about this guideline can be found here.
The ECA Education Course "GMP for Vaccine Manufacturers" in Heidelberg, Germany from 13-15 October 2010 will provide you with an insight in all GMP relevant aspects of vaccine manufacturing as well as regulatory requirements.
Axel H Schroeder
On behalf of the European Compliance Academy (ECA)