Clinical Research Directory

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: * Be a participant on the PREVAIL VIII/HONOR study. * Be at least 18 years of age. * Be scheduled to undergo or have undergone IGRA at a Month 12 HONOR study visit. * Ability to return to the clinic 48 to 72 hours after TST placement for reading. * Ability to provide informed consent. In order to be eligible to participate in the extension phase of the study, an individual must meet all of the following criteria: * Participated in the PREVAIL VIIIa HONOR TB study. * Have had a positive TB test result on the TST and/or IGRA performed as part of the PREVAIL VIII HONOR or PREVAIL VIIIa HONOR TB study(ies). * Ability to provide informed consent. EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: * Received BCG vaccine \<=10 years prior. * Known hypersensitivity or allergy to any component of the PPD product. * Previous severe reaction (e.g., necrosis, blistering, ulcerations, or anaphylactic shock) to a TST. * Documented active TB or a clear history of treatment for latent infection or active disease. * Extensive burns or eczema or other skin conditions on the forearms that could affect placement and reading of the TST. * Pregnant or lactating women. * Any condition that, in the opinion of the investigator, would compromise the safety of the study participant or staff, or would prevent proper conduct of the study. An individual who meets any of the following criteria will be excluded from participation in the extension phase of this study: * Pregnant women. * Contraindication to CT scanning. * Any condition that, in the opinion of the investigator, would compromise the safety of the study participant or staff, or would prevent proper conduct of the study. Exclusion of Special Populations (Children, Adults Who Lack Capacity to Consent, and Pregnant Women) -We are able to obtain knowledge about TST performance in Liberia without exposing children, adults who lack capacity to consent, and pregnant women to the potential risk of reactions to the TST or exposure to radiation for research purposes.