Tuberculin test, oral BCG vaccine, and tuberculosis infection among children under five years of age

Abstract

Results of tuberculin reaction from PPD Rt 23, 2UT are reported on children under one year of age and children from one to four years of age who were registered in the Pediatric Clinics of the Hospital das Clinicas of the College of Medicine of the State University of São Paulo. The study was carried out from 1971 through 1975. In a group of 665 children under one year of age, 3.15% were weak reactors while 6.62% were strong reactors, and, in a group of 1298 children between one to four years of age, 0.69% were weak reactors while 5.5% were strong reactors. The relationship between prior BCG oral vaccination and positivation to the tuberculin test in the two age groups was studied, thus obtaining information about the previous oral BCG vaccination. Likewise, in 575 children under one year of age and 1113 children one to four years of age, a positive relationship between the previous oral administration of BCG and the positivation to the tuberculin test was found. In analyzing the relationship between the number of doses of previous oral BCG administration and the results of the tuberculin test by the Goodman method, it was found that the proportion of children who had taken three or more doses of BCG by oral administration and showed strong reaction to the tuberculin test is significantly greater than that observed for the non-reactors, a fact which does not hold true for the one to four age group. For the children who had taken one or two doses there was no significant statistical difference.