Comparison two methods- plaque forming unit (PFU) and cell culture infectious dose 50% (CCID<sub>50</sub>) for potency assay of the national standard measles vaccine

Abstract

A comparative study of two methods (PFU and CCID50) for potency determination for the national standard candidate measles vaccine was organized at the National Institute for Control of Vaccines and Biologicals (NICVB). Two methods are performed on the groups of candidate measles vaccine derived from AIK-C strain stored at different temperatures: -70oC, 4oC/7 days, 37oC/7 days. The results show that although there is a difference, strong correlation exists between the two methods CCID50 and PFU with R2 = 0.886, r = 0.94, coefficient PFU/ CCID50 = 1.28 equivalent to the ratio PFU: CCID50 = 1:0.78