Risk of TB infection
Certain living or working conditions make it easier for the disease to pass from one person to another. These conditions increase the risk of getting a TB infection:
Living with someone with active TB disease.
Living or traveling in a country where TB is common, including several countries in Latin America, Africa, Asia and the Pacific Islands.
Living or working in places where people live close together, such as prisons, nursing homes and shelters for homeless people.
Living in a community identified as being at high risk of tuberculosis.
Working in health care and treating people with a high risk of TB.
Risk of active TB disease
A weakened immune system increases the risk of a TB infection becoming active TB disease. Conditions or treatments that weaken the immune system include:
HIV/AIDS.
Diabetes.
Severe kidney disease.
Cancers of the head, neck and blood.
Malnutrition or low body weight.
Cancer treatment, such as chemotherapy.
Drugs to prevent rejection of transplanted organs.
Long-term use of prescription steroids.
Use of unlawful injected drugs.
Misuse of alcohol.
Smoking and using other tobacco products.
Age and active TB disease
The risk of a TB infection becoming active TB disease changes with age.
Under 5 years of age. Until children reach age 5, they have high risk of a TB infection becoming active TB disease. The risk is greater for children under age 2. Tuberculosis in this age group often leads to serious disease in the fluid surrounding the brain and spinal column, called meningitis.
Age 15 to 25. People in this age group have an increased risk of developing more-severe active TB disease in the lungs.
Age 65 and older. The immune system weakens during older age. Older adults have a greater risk of active TB disease. Also, the disease may be more difficult to treat.
