Natural History of Tuberculosis in the Human Body

IX. Prognosis Among Students with Tuberculin Reaction Conversion Before, During and After Medical School

¹ School of Public Health and the Department of Internal Medicine, the Medical and Graduate Schools, University of Minnesota

The 2908 students of medicine in the classes of 1930-1953, University of Minnesota were followed 78,635 person-years. The whereabouts of 12 were not determined and nontuberculous conditions had caused death of 220. The remaining 2676 responded to the survey.

The tuberculin test served to identify those students who harbored tubercle bacilli. Since only reactors develop clinical tuberculosis, it was important to find and keep them under surveillance.

Among 904 survivors who reacted to tuberculin on entrance to school and were followed 25,538 person-years, 31 (3.43 per cent) developed clinical pulmonary or extrathoracic tuberculous lesions and three had only pleurisy with effusion. One died from tuberculosis.

Among the 447 surviving physicians followed 13,667 person-years, who became infected while in school and 622 followed 16,977 person-years, who were infected after graduation, 19 (1.68 per cent) developed pleurisy with effusion only and 41 (3.83 per cent) had clinical pulmonary or extrathoracic lesions evolve. Two died from tuberculosis.

Among the students of this school who graduated in the classes from 1919 to 1932, 92, (7 per cent) developed demonstrable tuberculous lesions while in school or soon after whereas in the subsequent classes through 1953, the last clinical case among students developed in 1946 and the last case among graduates occurred in 1956. None developed meningitis or miliary dissemination.

Although the accomplishment is gratifying, the problem will not be solved as long as infected students enter the medical school, and infections occur among students.