Government of India set up a plant for producing Freeze-Dried vaccine at BCG Vaccine Laboratory, Madras in 1959. Before releasing the freeze-dried vaccine to the mass campaign it was necessary that it is subjected to various tests. This paper deals with two such trials. The first study planned in this connection was for the assessment of allergising properties of two lots each of four batches of freeze-dried vaccine. The second study was to investigate the stability of two lots of a batch of freeze-dried vaccine in relation to storage at different temperatures for varying periods.

The results indicate that though the liquid vaccine has on the whole produced slightly higher allergy than the freeze-dried vaccine, the level of allergy achieved with the freeze-dried vaccine is quite adequate. Levels of post-vaccination allergy in the lots containing glutamate and tween 80, show that increase in storage temperature has resulted in higher loss of potency of vaccine. No definite trend is indicated regarding the lots containing glutamate alone.