Chemoprophylaxis trial in Canadian Eskimos

One hundred and two cases of inactive tuberculosis, 165 positive tuberculin reactors and 103 previous BCG vaccinated individuals showing large tuberculin reactions were placed on the completely supervised regimen consisting of isoniazid and ethambutol given three times a week. Over 90% of these individuals completed 18 months' treatment. There were no active cases of tuberculosis among the treated groups during the observation period averaging 34.8 months. The control groups consisting of 217 individuals had 9 cases of active tuberculosis giving an annual risk of developing the disease of 1.8 per 1000.