What is the difference between latent TB and active TB?
Latent TB is when the body’s immune system forms a wall around the TB bacteria so the TB bacteria cannot multiply or spread. The TB germs are essentially “asleep” in your body when you have latent TB. A person with latent TB is not contagious (cannot spread TB to other people) and has no symptoms. TB bacteria can stay latent for long periods of time (e.g. from many years to the rest of your life). Active TB is when the body cannot adequately fight the TB bacteria. The person has symptoms and can be contagious when TB infects the throat or lungs and the person has a cough.
