Assessing the Impact of Interventions on Tuberculosis Control: India Based Modelling Framework

Background

India accounts for nearly one-fourth of the global tuberculosis (TB) burden. The country’s progress towards elimination of TB is hindered by considerable heterogeneity in behavioural, social, and health system determinants, which influence transmission dynamics and care access. Evidence from the recent national TB prevalence survey showed that almost half of individuals with active disease were asymptomatic, underscoring the limitations of symptom-based case finding. Achieving the End TB targets will therefore require strategies that simultaneously address the substantial pool of individuals with undiagnosed, asymptomatic disease and those symptomatic individuals who do not seek care.

Methods

We developed a transmission model of TB that explicitly incorporates individuals with asymptomatic disease, and those who do not seek care. Model calibration was performed within a Bayesian framework using epidemiological and programmatic data for India. The calibrated model was then used to project the potential impact of intervention on TB incidence and mortality.

Results

Under the baseline scenario, the estimated TB incidence and mortality rates for 2024 were 180 (163-203) and 24 (18–31) per 100,000 population, respectively. Across all intervention scenarios targeting improved diagnosis, active case finding, nutrition support and their combination the reduction in incidence rate by 2030 ranged from 13% to 60% compared with 2025, while the corresponding decline in mortality rate ranged from 16% to 66%.

Conclusion

While individual interventions yield measurable reductions in TB incidence and mortality, but greater impact is achieved when implemented in combination reflecting the need for a comprehensive, multi-component response towards TB elimination.

What is already known on this topic

• Studies have analysed the impact of single intervention scenarios across different regions and India

What this study adds

• We developed a dynamic model of tuberculosis in India, modelling the impact of four different interventions: nutritional support, health facility improvements, active case finding and a combination of all three.

• We found that a single intervention cannot be considered powerful enough to improve the rate of decline of incidence and mortality and so a multi-sectoral intervention scenario is required.

How this study might affect research, practice or policy

Accelerating the decline in tuberculosis burden requires interventions targeting the entire care cascade while simultaneously providing nutritional support.