[BCG vaccination and leukemia. Epidemiologic studies on the effect of BCG vaccination on leukemia]

The possible influence of BCG vaccination on leukemia mortality of infants was investigated by various authors. The methods used were prospective trials, retrospective studies and epidemiological analyses. In some of these studies a protective effect of BCG vaccination was observed, in other studies no influence was found. Up to now this problem is subject to controversial discussions. An epidemiological analysis of the Austrian data using trend analyses, regression analyses and analyses of rank correlation showed an inverse correlation between BCG vaccination rate of newborns and leukemia mortality in the age group 0--5 years. From this correlation a protection rate of 0.77 could be calculated.