Rapid establishment and validation of a PMAxx-RT-qPCR method for infectious titer detection of freeze-dried live attenuated hepatitis A vaccine (H2 Strain).

The infectious titer of hepatitis A virus (HAV) is a critical quality parameter for evaluating potency of freeze-dried live attenuated hepatitis A (HepA-L-fd) vaccines. In this study, we developed a rapid PMAxx-RT-qPCR for detecting the infectious titer of HepA-L-fd vaccines. This method enables virus titer detection to be completed within a day. Systematic optimization of experimental parameters yielded a validated methodology demonstrating excellent precision (coefficient of variation, CV < 1 %), accuracy (recovery rate 107.6 ± 3.7 %), and a linear range of 6.23-7.73 log10CCID50/mL. Comparing with the measurements from the traditional method, results showed no significant differences among the six batches of vaccine finished products (P = 0.7452). This optimized PMAxx-RT-qPCR assay provides a rapid and reliable analytical means for the infectious titer assay in HepA-L-fd vaccines.