ANTIGENIC ACTIVITY OF FRESH, FROZEN, AND DRY BCG VACCINE

Abstract

The loss of living organisms is greater in drying glucose BCG vaccine from the frozen state than in simple freezing. Dry glucose BCG vaccine retains a stable numerical level of living organisms for one year when kept at 2[degree]-4[degree]C whereas frozen glucose BCG vaccine gradually falls in level of living population to a lower figure even when kept at -20[degree]C. In any case the morphological, cultural and biological characteristics of the living organisms remain unaltered. The antigenicity of the dry processed vaccine is lower than that of the fresh liquid prepn. However, by increasing the number of skin punctures[long dash]which amounts to introduction of near equal numbers of living organisms[long dash]comparable antigenicity can be attained.