Lack of evidence for a reduction in the efficacy of subcutaneous BCG vaccination in mice infected with nontuberculous mycobacteria.

Subcutaneous BCG vaccination of mice several weeks after intravenous or subcutaneous infection with either M. avium or M. kansasii had no effect on the subsequent course of these nontuberculous mycobacterial infections. In some animals the growth of the BCG infection in the draining popliteal lymph nodes was reduced compared with the growth in controls, although these mice were as resistant as BCG-vaccinated controls to a subsequent airborne challenge infection with M. tuberculosis. Nonvaccinated previously infected mice also showed some degree of resistance to the airborne challenge infection; this resistance was more pronounced in mice infected with nontuberculous mycobacteria intravenously than in those infected subcutaneously.