Tuberculosis in Bacillus Calmette-Guérin- immunized and unimmunized children in Sweden a ten-year evaluation following the cessation of general Bacillus Calmette-Guérin immunization of the newborn in 1975

Abstract

An analysis was made of childhood tuberculosis in Sweden between 1969 and 1984 which included the 6.25 years before and the 9.75 years after the cessation of general Bacillus Calmette-Guerin (BCG) immunization of the newborn on April 1, 1975. The annual incidence of tuberculosis per 100 000 children ages 0 to 4 years increased from an average of 1.1 cases in the period 1970 to 1974 to 1.3 cases in the period 1975 to 1979 and to 2.1 cases in the period 1980 to 1984, including both children born in Sweden and those born abroad. Among children born in Sweden after April 1, 1975, tuberculosis occurred in 58 (57 unimmunized and one BCG-immunized), or 1.3 cases per 100 000 person years up to and including 1984. Eighteen of the 58 chilren were asymptomatic. Minor symptoms were reported in 13 and clinical illness in 27 children, 2 of whom developed meningitis and 1 of whom died of miliary infection. The relative increase in tuberculosis in the mainly unimmunized cohorts born in Sweden after April 1, 1975, compared with the mainly BCG-immunized cohorts born in Sweden in the period 1969 to 1974 was, by the end of 1984, estimated at 6.0 (95% confidence interval, 2.3, 16.1). Tuberculosis was about 10 times more common in non-BCG-immunized children born in Sweden of foreign parents than in those born of Swedish parents. The number of cases of tuberculosis that could have been prevented in children born of Swedish parents was too few to justify the reintroduction of general BCG immunization of the newborn. However, the children of foreign parents still need to be protected by BCG immunization also when they have been born in Sweden.