Influence of MPR revaccination on tuberculin and sensitin skin reactions in children.

Many viral diseases, as well as viral vaccines, have a transient effect in depressing cell-mediated immunity. The study group consisted of 52 children, aged 6.0-6.3 years. Thirty (57%) of them had been revaccinated against measles, parotitis and rubella (MPR vaccination). In MPR-revaccinated children, the mean skin reaction sizes were 4.7 mm, 4.1 mm, 4.3 mm and 2.1 mm to tuberculin, Mycobacterium avium, M. scrofulaceum and M. fortuitum sensitins, respectively. In non-revaccinated children (n = 22), the respective mean skin reaction sizes were 3.0 mm, 2.8 mm, 2.9 mm and 0.8 mm. The difference between re- and non-revaccinated children was statistically significant with regard to reactions to M. fortuitum sensitin (p < 0.05). These results suggest that the influence of viral revaccination is different from natural infection or primary vaccination. The mechanism of stimulation of cell-mediated immunity--either specific or non-specific--is unknown.