Effect of adjuvant on preservability of dried BCG vaccine at 37 degrees C

Abstract

Experiments were carried out to determine the effect of various adjuvants on the preservability of dried BCG vaccine at 37 degrees C. The substances tested included carbohydrates, proteins, amino-acid derivatives, synthetic polymers, peptides and polypeptides, and various combinations of protein, sugar, and salt.The resulting vaccines were preserved for periods of up to 8 months at 37 degrees C, and were then subjected to culture tests. The highest BCG survival-rate was obtained with sodium glutamate vaccine, no significant difference being observed between the survival-rates with l- and with dl-sodium glutamate. Of the three concentrations of sodium glutamate tested-that is, 1%, 5%, and 10%-the 1% concentration gave the highest survival-rate.From the results obtained with 1% sodium glutamate as adjuvant-a survival-rate per original suspension of about 10% and a viable-unit level of about 10 in 10(-6) mg of bacilli after 6-8 months' preservation-it may be concluded that it is possible to produce a dried BCG vaccine the viability of which will not be adversely affected by storage for several months at room temperature, even in hot climates.