Epidemiological basis of tuberculosis eradication. 4. The isoniazid trial in Greenland

Abstract

As knowledge of the epidemiology of tuberculosis in Greenland has increased, it has become evident that the majority of cases develop long after the primary infection and that it would therefore be valuable from the public health point of view if the disease rate among naturally infected persons could be reduced. To examine the possibility of achieving this, a double-blind drug trial with isoniazid and a placebo was conducted among some 70% of the adult population of western Greenland. The results show that throughout the six years of the study the incidence of tuberculosis was lower in the group treated with isoniazid and that this reduction occurred whether the initial X-rays pictures were normal or showed suspicious or healed lesions.It is concluded that chemoprophylaxis programmes should probably be administered only to selected groups of the population. The delimitation of such groups is discussed on the basis of their tuberculosis risk and of the expected yield in terms of reduction in tuberculosis prevalence.