Estimated health and economic benefits in Canada of reduced tuberculosis transmission in key source countries of immigration: a Markov modelling analysis

Abstract Background Tuberculosis remains the leading cause of death due to a single infectious agent globally, responsible for 1.23 million deaths in 2024 alone. In Canada, approximately 80% of people who develop tuberculosis disease are foreign-born, typically reflecting the progression of tuberculosis infection acquired prior to immigration. Overseas investments in tuberculosis prevention and care programs in high-burden, key-source immigration countries may therefore represent a valuable strategy for improving tuberculosis epidemiology among foreign-born Canadians. We aimed to quantify the potential downstream impacts of improved tuberculosis epidemiology overseas on tuberculosis-related outcomes among foreign-born Canadians. Methods An open-cohort Markov microsimulation model was used to simulate tuberculosis epidemiology among foreign-born Canadians between 2001 and 2050. We modelled a status quo scenario and four reduction scenarios where additional 1–4% reductions in annual risk of tuberculosis infection were applied to current trends among foreign-born individuals from China, India, the Philippines, and Vietnam beginning in 2025 and continuing until 2050. Key outcomes included Canadian healthcare system costs, tuberculosis infection cases, tuberculosis disease cases, tuberculosis deaths, and quality-adjusted life years. Incremental net monetary benefit was calculated using a willingness-to-pay threshold of $100,000 per quality-adjusted life year gained. Results The largest health and economic gains between 2025 and 2050 were predicted among foreign-born individuals from India and the Philippines. The number of tuberculosis cases averted among foreign-born individuals from India ranged from 68 to 230 in the 1% and 4% reduction scenarios, respectively, compared to 73 and 246 cases averted among those from the Philippines. Incremental net monetary benefit was highest among individuals from India ($3.4–12 million with 1–4% reductions), followed by those from the Philippines ($2.4–8.6 million). Incremental net monetary benefit was predicted to be substantially lower among individuals from China ($0.8–2.6 million) and Vietnam ($0.1–0.3 million). Conclusion Our findings suggest that improvements in tuberculosis epidemiology in high-burden, key-source immigration countries—particularly India and the Philippines—have the potential to generate meaningful downstream economic and health benefits among foreign-born Canadians. Moreover, the gains achieved in Canada would represent only a portion of the larger global benefit. Future modelling work should focus on identifying specific interventions capable of achieving such benefits in a cost-effective manner.