IFNG and tuberculosis: Reference tests for TB (chest radiographs and sputum tests for GeneXpert MTB/RIF Ultra®, Auramine smear and liquid cultures) and investigations to classify infection states [interferon-gamma release assay (IGRA) and SARS-CoV-2 polymerase chain reaction (PCR) nasopharyngeal swab and IgG], are done on all participants who meet the inclusion criteria.