A System Dynamics model of tuberculosis diffusion with respect to contact tracing investigation

Despite great efforts to control the spread of tuberculosis (TB), the disease remains stubbornly persistent, having infected one third of the world population, and causing more than 1.5 million deaths annually. To better understand the epidemiology of TB, past modeling efforts have sought to understand how TB prevention and control policies affect infection spread in the population. This paper describes a preliminary dynamic model to evaluate the role of current contact tracing policies in managing TB transmission. Through a novel representation of contact tracing dynamics, the model supports investigation of how TB outcomes are affected by changes to the breadth and timeliness of contact investigation. Model results suggest that while successful contact tracing is self-limiting, it plays a critical role in TB control. Results also suggest that expanded breadth of contact tracing offers diminishing returns, and underscores the desirability of highly targeted contact tracing and the desirability of richer models.