EXPIRATION PREDICTION OF NATIONAL JAPANESE ENCEPHALITIS STANDARD VACCINE STRAIN NAKAYAMA

Abstract

Quality control plays an important role to determine the safety and efficiency of a vaccine, which includes potency, an essential test to evaluate vaccine’s quality. National Japanese encephalitis (JE) standard vaccine produced in 2003 (code MCQG/01) has been used as reference for calculation of commercial inactivated JE vaccine. The expired date of national JE standard vaccine in 2003 was determined as 11 years 7 months, however, until now, there is no project of retest or expired date prediction for this standard vaccine. Therefore, this project is carried out with the purpose of predicting new expiration for national JE standard vaccine by accelerated stability test at 3 temperatures 4°C, 25°C and 37°C in 2 weeks, 4 weeks, 6 weeks, 8 weeks and 10 weeks. Plaque reduction neutralization test 50% (PRNT₅₀) is applied to calculate potency value of JE standard vaccine at each temperature and each period of time, and then input in JMP Pro software based on Arrhenius equation to determine the expiration. The result showed that it took about 17,2 years or 912,46 weeks for potency alue of national JE standard vaccine down to lower limitation (=1,30 log PRNT₅₀). Therefore, the national JE standard vaccine strain Nakayama is still ensured to apply for routine procedure at National Institute for Control of Vaccines and Biologicals (NICVB).