To be eligible for the study [42], participants had to be HIV-positive, at least 18 years of age, with a CD4 T cell count of at least 200 cells/mL, a visible BCG scar from childhood immunization (sensitivity > 90%, as reported in a study conducted in the Malawi region [166]), a negative pregnancy test, and no evidence of active TB. Here, CD4 is linked to tuberculosis.