TB infection progressing to TB disease

Why does TB infection progress to TB disease?

A person with TB infection may develop TB disease if their immune system can't stop the bacteria from growing. The highest risk of TB disease is within the first 2 years of becoming infected. After the first 2 years, there is about a 10 % chance of developing TB disease in a person's lifetime. This often happens when their immune system weakens.

Who is more likely to get TB disease?

People with weakened immune systems are more likely to get TB disease. Babies, preschool children and the elderly have weaker immune systems than healthy adults. People with TB and HIV infection have very weak immune systems. The following conditions also weaken the immune system:

• organ transplants
• low body weight
• silicosis
• abuse of alcohol or drugs
• end stage kidney disease
• leukemia or Hodgkin's disease
• cancer of the head or neck
• abnormal chest x-ray
• diabetes
• corticosteroids, radiation
• cancer
• chemotherapy

What can I do to prevent progression to TB disease?

If you have TB infection, it is important to protect your immune system from becoming weak. Treatment of TB infection with antibiotic(s) will help your immune system fight the TB bacteria and prevent TB disease. Knowing your HIV status will help you take special precautions if you have both TB and HIV infection.

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[Tuberculosis FACT SHEET - Index]