Modelling the sustainability of TB-funded prevention programs in the presence of fear and stigma: implications on TB transmission dynamics

Abstract Tuberculosis (TB) remains a major public health concern, particularly in resource-limited settings where sustained funding and psychosocial factors critically influence disease dynamics. This study presents a novel mathematical model that integrates fear, stigma, and funding to assess the sustainability of TB-funded prevention programs. The model, formulated as a system of nonlinear differential equations, analyses disease-free and endemic equilibria and investigates the conditions under which TB transmission can be effectively reduced. Our results show that consistent financial investment is essential for long-term TB control, eliminating backward bifurcation and ensuring that reductions in the basic reproduction number ( $\mathcal{R}_{0}$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>R</mml:mi> <mml:mn>0</mml:mn> </mml:msub> </mml:math> ) translate into sustained declines in TB incidence. We introduce a funding sustainability ratio that provides a quantitative threshold for maintaining effective program outcomes. Simulations reveal that enhanced prevention efforts and health education, supported by stable funding, significantly lower TB prevalence and the size of the stigmatised infectious population. The study further reveals a counterintuitive effect of fear, as moderate levels encourage preventive behaviours, whereas excessive fear intensifies stigma and discourages timely treatment seeking, thereby prolonging transmission. Our findings emphasise that health education alone is insufficient without sustained financial support. Moreover, fear-driven isolation may reduce short-term transmission but imposes substantial social costs. These results underscore the importance of integrating biomedical interventions with targeted psychosocial strategies, underpinned by long-term, stable funding, to achieve sustainable TB control in high-burden communities.