WHO informal consultation on characterization and quality aspect of vaccines based on live viral vectors, December 2003
Reference materials and standardization
A range of viruses, including adenoviruses, parvoviruses (adeno-associated virus), poxviruses (vaccinia, canarypox), positive-strand RNA viruses (SFV, SINV, VEE, YFV, poliovirus, Kunjin virus), negative-strand RNA viruses (influenza virus, Sendai virus) and double-strand RNA viruses (rabies virus, vesicular stomatitis virus, retroviruses) have been considered for the development of vectored viral vaccines. This intended use raises a number of standardization issues, including comparability of results of infectivity and potency assays among laboratories, dose definition of product and what reference materials are appropriate for assay calibration and sensitivity monitoring. These issues relate not only to quality and efficacy, but also to safety. For some viruses, determination of virus particle number is paramount in assuring safety, e.g. for adenovirus, which is markedly toxic at high dose levels, while for others this may be less important. For instance, infectivity and antigenicity as measured in functional assays, are for many viruses important characteristics for determining safe, efficacious doses when used as vaccines. However, currently there are very few reference materials universally available for standardization purposes. Only in the area of Ad vectors has there been concerted international action to produce and characterize a suitable reference material..... click on link below for full text