Reduced incidence of tuberculosis by prophylactic chemotherapy in subjects showing strong reactions to tuberculin testing.

The introduction of chemoprophylaxis with rifampicin and isoniazid in 1981 significantly reduced the incidence of tuberculosis. Between 1978 and 1981 children accounted for 136 of 642 notified cases, and this was reduced to 55 of 418 between 1982 and 1986. This effect was most obvious among children from the Indian subcontinent who comprised 80.2% of the children treated. The incidence among white children was not affected. Few side effects occurred and only two of 339 (0.6%) later developed clinical tuberculosis. Chemoprophylaxis plays an important part in the management of tuberculosis in a district with a high incidence of the disease.