Stability of the Industrial Reference Standard of Tuberculosis Vaccine (BCG)

The industrial reference standard of tuberculosis (BCG) vaccine (IRS), certified and registered by the Federal State Budgetary Institution “Scientific Centre for Expert Evaluation of Medicinal Products” of the Ministry of Health of the Russian Federation (OSO 42-28-420), is used as a reference product in quality control of tuberculosis vaccines BCG and BCG-M. The IRS is a useful means of quality control of these products, as the stability of its proper ties helps to minimise errors during quality evaluation. The shelf life of the BCG vaccine IRS is not more than 2 years if stored at 2–8 °C. It is likely that a vaccine batch could be used as the IRS for a longer period of time. The literature data suggest that the shelf life of a BCG vaccine can be prolonged if it is stored at low temperatures. However, due to significant phenotypic and genotypic differences between BCG sub-strains, the extrapolation of these data to the vaccine produced from the Russian Mycobacterium bovis BCG-I sub-strain requires appropriate testing. The aim of the study was to analyse the possibility of increasing the shelf life of the tuberculosis vaccine IRS by changing the storage temperature. Materials and methods: the effect of low temperatures on the stability of OSO 42-28-420 was studied in commercial batches of tuberculosis vaccine which met all the quality requirements for candidate IRSs. Samples from 6 IRS batches produced from 2014 through 2019 were stored at –(20 ± 1) °С. The stability of their quality characteristics, namely “Specific activity (viability)”, “Total bacterial count”, and “Dispersibility”, was monitored according to the recommendations of the World Health Organization. The obtained data were evaluated relative to the baseline data obtained during certification of each batch. Results: it was demonstrated that there was more than 95 percent probability that the tested parameters would not differ from the initial data if OSO 42-28-420 samples were stored at a low temperature for 5 years. Conclusions: the results obtained support the prolongation of the OSO 42-28-420 shelf life up to 4 years under the recommended storage conditions at –(20 ± 1) °С.

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