ABSTRACT
A retrospective case control study was carried out between 1981 and 1984 in three hospitals in the western part of Greater Buenos Aires to determine protection provided by BCG tuberculosis vaccine in children under six years of age residing in a region of Argentina in which vaccination coverage is approximately 55 percent. A total of 175 cases of tuberculosis were included in the study. For each case five controls were selected (a total of 875) from among patients being treated in the same hospital for other causes unrelated to tuberculosis. The controls were selected on the basis of their similarity with the cases with respect to age, socioeconomic status, nutritional status, and place of residence. Information on the presence or absence of vaccination scarring and other data related to vaccination of both the cases and controls was collected by an independent examiner. In 152 of the 175 cases location of tuberculosis was pulmonary; in 15, miliary; and in six there were pleural complications. Of the remaining 23 cases, 18 were meningeal, two gangliar, two osteoarticular, and one otic. Diagnosis was based on bacteriological and histopathological analysis, computerized tomography, radiological and clinical examination, endoscopy, and verification of a focus of infection. The protective effect of BCG vaccine in vaccinated patients was 73 percent on average (CI95 percent = 62 to 85 percent