[Evaluation of screening for tuberculosis in a population of apprentices and high school children]

Taking into account the present epidemiological situation the health authorities of the Canton of Vaud, Switzerland, have decided to modify the strategy of tuberculosis prevention in children and adolescents by abandoning routine chest radiophotography while maintaining the tuberculin skin test. The present study focuses on the detection and follow-up of adolescents presenting with a positive tuberculin reaction at the first routine school health visit. As part of routine prophylactic school health measures, 753 boys and 1043 girls, aged 16 to 20, received 2 units of Danish tuberculin intradermally. 48 to 72 hours later, 100 subjects (5.6%) exhibited a pathological reaction and were sent to their doctors for further evaluation. 10% did not attend. Among the 90 remaining, the positive reaction to tuberculin test was not confirmed by the private physician in 48 (predictive value of the test: 47%). Among the 42 subjects for whom the reaction was confirmed, 39 had post-BCG vaccinal conversion and 3 spontaneous conversion. The prevalence of tuberculous infection was thus 2.3% (42/1796). Among the 42 positive subjects, only 18 (43%) were given preventive isoniazide treatment as recommended by the Association Suisse contre la Tuberculose et les Maladies Pulmonaires. Instruction on tuberculin testing and its interpretation must be improved, as must information regarding the prophylaxis and treatment of tuberculosis infection.