Studies on the influence of BCG vaccination on infantile leukemia.

In the situation of low and decreasing risk of tuberculosis the possible non specific effect of BCG vaccination against leukemia becomes more and more important. To answer this question several studies using epidemiological and clinical data of children up to 5 years were performed in Austria. The following parameters which might be influenced by a possible protective effect of BCG vaccination were checked: leukemia mortality, case fatality, age of manifestation, frequency of different kinds of leukemia and the distribution of tuberculin reactions in leukemic and non leukemic children. All these parameters showed significant differences between vaccinated and non vaccinated leukemic and non leukemic children respectively making a protective effect of BCG vaccination against leukemia highly probable.