Sensitivity to sensitins and tuberculin in Swedish children. IV. The influence of BCG-vaccination.

BCG-vaccinated schoolchildren, 8-9 yrs of age, were simultaneously tested on separate arms with tuberculin and a sensitin. Using the 6 mm cut-off they reacted in 49% to two tuberculin units purified protein derivative (PPD RT23), in 67% to 0.1 micrograms Mycobacterium avium sensitin RS10, and in 58% to 0.1 micrograms M. scrofulaceum sensitin RS95. The corresponding figures for non-BCG-vaccinated schoolchildren of the same age tested at the same time were 3, 25 and 32%, respectively. The results indicate a stimulating influence of BCG-vaccination on tuberculin and sensitin reactivity. Since the sensitin reactions were the larger ones, these reactions were not only due to the vaccination. The BCG-vaccinated schoolchildren seem to have acquired infections by atypical mycobacteria despite vaccination.