[The role of preventive chemotherapy in the present tuberculosis epidemiology of GDR (author's transl)].

The risk of "Gesunde Befundträger" (healthy carriers of pulmonary lesions) to develop pulmonary tuberculosis is compared with that of persons with X-ray shadows in the lung. In the group of "Gesunde Befundträger" this risk can be further differentiated, being highest among males with positive tuberculin skin test and more extended X-ray shadows in the lung. Judging from a follow-up of 4 years in the double-blind trial on isoniazid preventive treatment in persons with fibrotic lesions, the risk of developing pulmonary tuberculosis is reduced by 2/3 by giving 300 mg isoniazid daily during 24 weeks. In the present epidemiological stage of tuberculosis in GDR, preventive treatment of persons with highest risk of developing tuberculosis disease is the most promising prophylactic measure. The recommedations to reduce side-effects must be observed.