Pulmonary Tuberculosis is a contagious infection usually developed after inhaling droplets sprayed into the air by a sneeze or cough.
It can spread from the lungs to the brain or any organ and it's been considered tough to treat. But ...just because someone tested positive on a skin test doesn't mean that the person has an active case of TB. An older person can test positive from exposure from decades before. Those who test positive will have more tests ...like a chest x-ray and speutem testing.
If the person tests positive and are symptomatic they will probably take several rounds of high powered antibiotics and be segregated from others. Some detective work will be done on those who test negative after the skin tests and it's possible that someone testing positive on the skin test will have nothing done. Others may have some preventive therapy.
Only about 10-percent of those who test positive in a skin test will get TB.