BCG and tuberculosis
As it happened, three different types of BCG were provided by the National Medical Stores during EMaBS enrolment. We found that the different BCG strains resulted in different levels of immune response to tuberculosis proteins and the percentage of children that developed BCG scars differed by BCG strain. In addition, the three strains were associated with differing responses to unrelated stimuli, such as tetanus antigen. In addition to protecting against the more severe forms of tuberculosis in infancy, BCG seems to have important general effects on the immune system, and these may differ according to the strain used (Anderson et al., 2012).