From 1953 to 1973, a series of 2,593 children with high-risk backgrounds completed a course of prescribed treatment for tuberculosis at the Children's Tuberculosis Clinic, Houston. Of 1,881 children with subclinical infection given isoniazid chemoprophylaxis, only six developed pulmonary tuberculosis, a morbidity of 3.2/1,000. There were 712 children with active tuberculosis at the initial clinic visit. Chemotherapy with drug regimens containing isoniazid successfully brought the disease to inactive status and also prevented the development of extrapulmonary tuberculosis and adolescent reactivation.
The results of the Houston study are contrasted with those of two pediatric studies reported immediately before the advent of isoniazid in 1951.
(JAMA 229:528-533, 1974)
Hsu KHK. Isoniazid in the Prevention and Treatment of TuberculosisA 20-Year Study of the Effectiveness in Children. JAMA. 1974;229(5):528–533. doi:10.1001/jama.1974.03230430020019