The bacteria causing tuberculosis can be divided into nine groups based on their genetic makeup. Each group has its own distribution with some being found globally and others limited to specific regions, and there are differences in how easily these bacteria can spread. In this study, the scientists will combine data on TB cases, their contacts, and bacterial genetics to understand why some genetic groups are more easily transmised in the diverse population. They will achieve this by building statistical models to quantify the effect of different factors, including bacterial genetic group and host genetics, on TB infection. By understanding these factors, they can develop better strategies to control the spread of TB and priorize interventions for those who are at higher risk.