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

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.