During the 19th century a staggering one in four people died from tuberculosis. Incidence steadily declined with socioeconomic improvements and medical advances such that by the 1980s tuberculosis was considered a disease of the past and control measures were relaxed. This approach was premature: rising incidence led WHO to declare tuberculosis a global emergency in 1993. Control efforts were re-intensified and although incidence has now peaked, world population growth means that absolute numbers remain stable. The costs involved are substantial, with an estimated US$6·9 billion spent on global tuberculosis control in 2017,1 yet the effectiveness of available interventions across different populations remains poorly understood...