Tuberculosis Screening of Immigrants to Low-Prevalence Countries: A Cost-effectiveness Analysis

All adult immigrant applicants to Canada undergo chest radiographic screening for tuberculosis (TB). Tuberculin skin testing could reduce the number of chest X-rays, and identify more candidates for prophylaxis. We modeled the cost-effectiveness of chest radiography and tuberculin skin testing for TB prevention over a 20-yr time frame, among three simulated cohorts of 20-yr-old immigrants. Compared with no screening, radiographic screening prevented 4. 3% of expected active TB cases in the highest risk cohort (50% TB-infected, 10% human immunodeficiency virus HIV seroprevalence), and 8. 0% in the lowest risk cohort (5% TB-infected, 1% HIV seroprevalence). Tuberculin skin testing further reduced the expected incidence 8. 0% and 4. 0%, respectively. Compared with no screening, radiographic screening cost 3, 943 Canadian per active TB case prevented in the highest risk cohort, and 236, 496 per case prevented in the lowest risk group. Compared with radiographic screening, mass tuberculin skin testing cost 32, 601 per additional case prevented in the highest risk group, and 68, 799 per additional case prevented in the lowest risk group. Chest radiographic screening of young immigrants from countries with a high prevalence of TB is a relatively inexpensive means of TB prevention. Tuberculin skin testing is considerably less cost-effective. For immigrants from low-prevalence countries, both interventions are extremely costly with negligible impact. The cost-effectiveness of either strategy would be greatly enhanced by increased adherence to chemoprophylaxis recommendations. Radiographic screening of groups with a high prevalence of tuberculous infection will then likely save money.