Lung Disease & Respiratory Health Center

People are at increased risk of infection with tuberculosis (TB) when they:

• Have close contact (such as living in the same house) with someone who has active TB, which can be spread to others. Active TB is very contagious.
• Are health professionals who may care for people with untreated TB.
• Live or work in crowded conditions where they can come into contact with people who may have untreated active TB. This includes people who live or work in prisons, nursing homes, military barracks, or homeless shelters.
• Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
• Travel to or from regions where untreated TB is common, such as Latin America (countries in Central America, South America, and the Caribbean), Africa, Asia, Eastern Europe, and Russia.

People who have an infection that cannot spread to others (latent TB infection) are at risk of developing active TB if they:

• Have an impaired immune system. The immune system may be weakened in older adults; newborns; women who have recently given birth; and people who have HIV infection, some cancers, or poorly controlled diabetes.
• Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
• Take some types of medicines, such as long-term corticosteroids, tumor necrosis factor-alpha antagonists (used to treat rheumatoid arthritis or Crohn's disease), or medicines to prevent rejection of a transplanted organ.
• Have a chronic lung disease caused by breathing in tiny sand or silica particles (silicosis) or celiac disease.²
• Have had gastric bypass surgery or a gastrectomy.
• Are 10% or more under their healthy body weight.