The long-term impacts of domestic and international TB service improvements on TB trends within the United States: a mathematical modelling study

Background: For low TB incidence settings, disease elimination is a long-term goal. We investigated pathways to TB pre-elimination and elimination (incidence <1.0 and <0.1 per 100,000, respectively) in the United States. Methods: Using a mathematical modelling framework, we simulated how U.S. TB incidence could be affected by changes in TB services in the countries of origin for future migrants to the United States, as well as changes in TB services inside the United States. We constructed intervention scenarios representing improvements in TB services internationally and within the United States, individually and in combination, plus a base-case scenario representing continuation of current services. We simulated health and economic outcomes until 2100. Findings: Under the base-case, U.S. TB incidence rates were projected to decline to 1.8 (95% uncertainty interval: 1.5, 2.1) per 100,000 by 2050. Intervention scenarios produced substantial reductions in TB incidence, with the combination of all domestic and international interventions projected to achieve pre-elimination by 2033 (2031, 2037). Compared to the base-case, this combination could avert 101 (84, 120) thousand U.S. TB cases and 13 (11, 16) thousand U.S. TB deaths over 2025-2050; the total economic value of these TB incidence reductions was estimated as US$68 (33, 112) billion. TB elimination was not projected before 2100. Interpretation: Strengthening TB services domestically, promoting the development of more effective technologies and interventions, and supporting TB programs in high-burden countries are key strategies for accelerating progress towards TB elimination in the United States. Funding: U.S. Centers for Disease Control and Prevention.