Fig. 1.

Overview of phases of Mycobacterium tuberculosis (M.tb) infection and sample collection. a Pathophysiology of TB. Major steps following from the initial exposure to M.tb are outlined, with the percentages of individuals progressing between steps taken from the WHO TB report¹⁴. b Schema of cohort collection. In this study, we focus on a genetic study between recently exposed active pulmonary TB cases (progressors) and subjects with tuberculin skin test (TST) positive results, who did not progress to active TB (non-progressors). Index cases had sputum with confirmed TB. Controls were recruited in the same household as index cases, with 12 month follow up periods to confirm infection status using TST