WHO Workshop on Standardization of Pneumococcal Opsonophagocytic Assay

Overview

Pneumococcal disease continues to be a major cause of morbidity and mortality among both the elderly and the very young. The prevention of pneumococcal infections is a prerequisite for achieving the rates of reduction in childhood deaths required to meet targets set as part of the Millennium Development Goals. A safe and effective pneumococcal conjugate vaccine is available and others, which are essential for a healthy marketplace, are under advanced development. Licensure of these new products will depend on the evidence of a functional immune response to vaccination.

WHO/IVB/QSS convened a meeting in Geneva, 25-26 January 2007, to review progress and formulate a plan for the international standardization of such a functional assay (Opsonophagocytic Assay,OPA) through a global forum including regulators, academia and industry. It was agreed that a stepwise, iterative, performance-based approach could be useful. Consequently, a three-phased strategy was developed. Sub-groups have been assigned to work on different components. It is anticipated that the product of this process, a standardized "reference" OPA method, will be established by WHO and published in the Technical Report Series to provide guidance to the regulators and manufacturers in the vaccine evaluation for licensure worldwide. This will facilitate the development of new pneumococcal vaccines, in particular in evaluating vaccine efficacy, and make the efficacy data comparable between different vaccines.