Can a person be infected TB without being infectious?

Yes, a person can be infected with tuberculosis (TB) without being infectious. This is known as latent TB infection (LTBI). People with LTBI have the TB bacteria in their bodies, but they are not sick and cannot spread the bacteria to others.

LTBI is usually caused by inhaling TB bacteria from someone who is sick with active TB. The bacteria can then settle in the lungs or other parts of the body, where they can remain dormant for many years.

LTBI is not contagious, but it can progress to active TB disease if the person's immune system becomes weakened. This can happen due to a number of factors, including:

* HIV infection

* Diabetes

* Cancer

* Organ transplant

* Certain medications

* Age (LTBI is more common in older adults)

People with LTBI can be treated with antibiotics to prevent them from developing active TB disease. Treatment is usually effective in preventing active TB disease, but it is important to complete the full course of treatment.