The potential impact of reductions in international donor funding on tuberculosis in low-income and middle-income countries: a modelling study

<h4>Background</h4>Tuberculosis programmes in many settings rely heavily on international donor funding. In 2025, the United States Agency for International Development (USAID) was dismantled, and other countries announced cuts to overseas development assistance. We quantified the potential epidemiological impacts on the tuberculosis burden attributable to these reductions in funding.<h4>Methods</h4>We calibrated a deterministic tuberculosis model of Mycobacterium tuberculosis transmission, progression, and care to epidemiological indicators in selected low-income and middle-income countries. Calibration was done with the history matching with emulation method, implemented with the hmer package in R and the Approximate Bayesian computation Markov Chain Monte Carlo method. We projected three future scenarios with the following assumptions: that levels of funding in 2024 would continue, that USAID funding would be terminated from 2025, and that additional reductions in funding through The Global Fund to Fight AIDS, Tuberculosis and Malaria would occur (alongside termination of funding from USAID) in line with current donor announcements from 2025. We assumed a reduction in tuberculosis treatment initiation rates proportional to budget reductions for each scenario, estimating cumulative excess episodes of symptomatic tuberculosis and tuberculosis deaths for each scenario.<h4>Findings</h4>We modelled 79 countries, representing 91% of global tuberculosis incidence and 90% of global tuberculosis mortality in 2023. Our modelling suggested that termination of USAID funding might lead to 1·4 million (95% uncertainty interval 1·1-1·7) excess tuberculosis episodes and 537 700 (451 900-662 300) excess deaths by 2035. Further reductions in funding in line with current announcements by the USA, France, the UK, and Germany could lead to 2·8 million (2·1-3·7), 257 600 (192 500-332 900), 206 000 (153 900-266 100), and 124 700 (93 200-161 000), additional episodes, respectively, of symptomatic tuberculosis and 1·0 million (0·8-1·3), 90 500 (72 400-112 800), 72 400 (57 900-90 100), and 43 800 (35 000-54 500) additional tuberculosis deaths, respectively, in the same period, relative to the scenario of termination of USAID funding.<h4>Interpretation</h4>We estimate substantial potential impacts on tuberculosis morbidity and mortality due to reductions in international donor funding. Expanded support from domestic and international donors is essential to address immediate gaps in services for prevention, diagnosis, and treatment.<h4>Funding</h4>None.