What is latent TB infection?
In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. The bacteria become inactive, but they remain alive in the body and can become active later. This is called latent TB infection. People with latent TB infection • have no symptoms • don’t feel sick • can’t spread TB to others • usually have a positive skin test reaction or positive TB blood test • may develop active TB disease if they do not receive treatment for latent TB infection Many people who have latent TB infection never develop active TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have weak immune systems, the bacteria become active, multiply, and cause TB disease.
In most people who breathe in TB bacteria and become infected, the body is able to fight the bacteria to stop them from growing. The bacteria become inactive, but they remain alive in the body and can become active later. This is called latent TB infection. People with latent TB infection: Have no symptoms Don’t feel sick Can’t spread it to others Usually have a positive skin test reaction Can develop active TB disease if they do not receive treatment for latent TB infection Many people who have latent TB infection never develop active TB disease. In these people, the TB bacteria remain inactive for a lifetime without causing disease. But in other people, especially people who have weak immune systems, the bacteria become active and cause TB disease.
• Most people who become infected with TB are able to fight the bacteria and stop them from multiplying. In many of these people, the bacteria become dormant. This is called latent TB infection. People with latent TB infection usually have a positive skin test reaction, but have no symptoms and cannot spread TB to others. TB bacteria remain alive in the body of those who have latent TB and can become active at a later point in time, if treatment is not received. The World Health Organization (WHO) estimates that approximately 5% to 10% of individuals infected with the TB bacteria actually become sick with the disease during their lifetime. For persons whose immune systems are weak, particularly those with HIV, the risk of developing active TB disease is considerably higher than for persons with normal immune systems. This is because in people who have weakened immune systems, the dormant TB bacteria can reactivate, thereby changing the person’s status from latent infection to active di
