Tuberculosis infection tests for contact screening in Brazil: a cost-effectiveness analysis

Background The World Health Organization has recommended three new tuberculosis (TB) antigen-based skin tests (TBST) (Diaskintest®, C-TST®, Cy-TB®) for the diagnosis of tuberculosis infection (TBI). Household contacts (HHC) of people with pulmonary TB are at increased risk for TBI. We evaluated the cost-effectiveness of the use of TBST and of QuantiFERON-TB Plus® (QFT-Plus®) compared to the tuberculin skin test (TST) in Brazil. Methods A state-transition Markov model simulating four distinct hypothetical cohorts of 10,000 HIV-negative contacts of different ages (3 months-4 years, 5-9 years, 10-14 years, and 15 or older) was built over five annual cycles for TBI testing and tuberculosis preventive treatment (TPT) under the Brazilian public health system perspective. Effectiveness was estimated from systematic reviews and costs were raised from the Brazilian government (TST and QFT-Plus®) and from the manufacturers (TBST). Incremental cost-effectiveness per TB case averted was calculated. Findings TBST has similar accuracy to QFT-Plus®, and all are more specific than TST. TBST are less costly compared with TST or QFT-Plus®. All TBST were cost-saving regardless of the age group compared to TST or QFT-Plus®. Cy-Tb® was the most cost-saving, followed by Diaskintest® and C-TST®. Interpretation The incorporation of the new TBST for screening in the Brazilian public health system would be a cost-saving alternative for contacts. Because these tests require the same infrastructure and human resources skills as TST, the tests could be readily implemented. Funding CNPq and Stop TB Partnership.