A comparison of the effectiveness of two freeze-dried BCG vaccines against Mycobacterium leprae in mice.

It has previously been shown that BCG vaccination affords mice protection against Mycobacterium leprae and most of this work was carried out using fresh liquid preparations of a strain originating from S. R. Rosenthal some years ago. In the present study, the effectiveness of the Japanese and Glaxo freeze-dried BCG vaccines was tested since such preparations would make it possible to administer vaccine of standard viability anywhere in the world, including leprosy-endemic areas. The Japanese and Glaxo vaccines, and the usual fresh liquid preparations, were administered in equivalent amounts to mice, which were then challenged with Myco. leprae. All the vaccines provided distinct protection. It was not possible, however, to say which vaccine was most effective because their optimal activities were not manifested at comparable times.