Comparison of Diagnostic Performance of C-Tb to QuantiFERON®-TB, in Combination With a Safety Assessment of C-Tb vs Tuberculin PPD RT23 SSI

Tuberculosis (TB) continues to be the most important bacterial infection worldwide and therefore new improved diagnostic tests are needed to help doctors in diagnosing TB. We are investigating a new skin test named C-Tb. Like the current tuberculin skin test (PPD), the C-Tb test is injected just under the skin and will, when positive, show redness and/or swelling at the injection site while a negative test will leave no reactions. The aim of this trial is to test the C-Tb skin test in volunteers. The volunteers are divided into four groups: * Negative control group: Must have no history of exposure to a person with tuberculosis disease. * Occasional contact: Must be in contact with a person with tuberculosis disease between 6 hours/week and 6 hours/day * Close contact: Must be in close contact with a person with tuberculosis disease for more than 6 hours/day for at least five days * Positive control group: Must have a confirmed tuberculosis disease within the last 3 years. The goals of this clinical trial are: * To compare the C-Tb test to a blood test, the QuantiFERON test. * To compare the C-Tb test to the PPD test that is currently being used. * To assess the safety of the C-Tb test.