Modified intra-cerebral challenge assay for acellular pertussis vaccines: Comparisons among whole cell and acellular vaccines

A WHO Working Group on Standardization of Acellular Pertussis Vaccines: potency assay met in Beijing, China, 7-9 November 2007. This group considered the report of this study, the comments of the participants and implications of the use of JNIH-3 as a reference standard and recommended establishment of JNIH-3 as an International Standard. The results of this study and the report of the Working Group were submitted to the Expert Committee on Biological Standardization (ECBS) of WHO which established JNIH-3 as the first International Standard for acellular pertussis vaccine in the modified intra-cerebral challenge assay and other protective bioassays with an assignment of 34 IU per ampoule in October 2008.