Vol. 9, Issue 1 (2020)

Author(s):
Raya Sarkar, Chanchal Guha, Ujjwal Biswas, Amaresh Chatterjee and Partha Sarathi Jani

Abstract:
The present study was conducted to evaluate the shelf life of live attenuated lentogenic strain PPMV-1 vaccine. Twenty four, 1 ml freeze dried vaccine vials were kept in the refrigerator at -120 ⁰C temperature. Each freeze dried vial contained 0.5 ml allantoic fluid containing live attenuated lentogenic strain PPMV-1 vaccine virus (local isolate) with addition of 0.5 ml cryoprotectant. HA titer as and EID₅₀ were estimated just before keeping in the storage (in refrigerator at -120 ⁰C temperature) and thereafter, every 15 days interval until the viability of the vaccine virus became nil. before freeze drying of the live attenuated lentogenic strain PPMV-1 vaccine (local isolate) the HA titer, EID₅₀ and number of dose of the vaccine per vial were 2¹⁰, 10^10.57 and 5874 respectively. After freeze drying, those values reduced to 2¹⁰, 10^10.37 and 3706.5 accordingly to HA titer, EID₅₀ and number of dose of vaccine per vial respectively. After keeping of the vaccine at -120 ⁰C temperature, the HA titer reduced to 2⁹ that had remained unchanged, up to 90 days of post storage study period. On the other hand, the EID₅₀ remained unchanged from the day of storage up to 90 days post storage study course at satisfied level. And, subsequently, the dose of the vaccine per vial also remained unchanged i.e. 3706.5 which was satisfactory up to the end of the study period. From the study it was concluded that freeze dried live attenuated lentogenic strain PPMV-1 vaccine (local isolate) had not lost its infectivity at -120 ⁰C within 3 months.