Deciding When to Treat Latent TB Infection

People with latent TB infection do not have symptoms, and they cannot spread TB bacteria to others. However, if TB bacteria become active in the body and multiply, the person will go from having latent TB infection to being sick with TB disease. For this reason, people with latent TB infection are often prescribed treatment to prevent them from developing TB disease. Treatment of latent TB infection is essential for controlling and eliminating TB in the United States.

Treatment of latent TB infection should be initiated after the possibility of TB disease has been excluded.

Groups Who Should be Given High Priority for Latent TB Infection Treatment

People with a positive IGRA result or a TST reaction of 5 or more millimeters

• HIV-infected persons
• Recent contacts of a TB case
• Persons with fibrotic changes on chest radiograph consistent with old TB
• Organ transplant recipients
• Persons who are immunosuppressed for other reasons (e.g., taking the equivalent of >15 mg/day of prednisone for 1 month or longer, taking TNF-α antagonists)

People with a positive IGRA result or a TST reaction of 10 or more millimeters

• Recent immigrants (< 5 years) from high-prevalence countries
• Injection drug users
• Residents and employees of high-risk congregate settings (e.g., correctional facilities, nursing homes, homeless shelters, hospitals, and other health care facilities)
• Mycobacteriology laboratory personnel
• Children under 4 years of age, or children and adolescents exposed to adults in high-risk categories

Persons with no known risk factors for TB may be considered for treatment of LTBI if they have either a positive IGRA result or if their reaction to the TST is 15 mm or larger. However, targeted TB testing programs should only be conducted among high-risk groups. All testing activities should be accompanied by a plan for follow-up care for persons with TB infection or disease.