Is latent TB contagious?

• A. Not contagious, but can become active w/o tx
• B. Contagious
• C. Contagious only with HIV
• D. Not contagious unless in hospital

Answer: (A)

Latent TB infection means the bacteria are present but dormant and contained within the body, so there are no symptoms and it cannot be spread to others. If latent TB isn’t treated, it can reactivate later and become active TB, and once active, the infection can be transmitted through the air when the person coughs, sneezes, or talks. So the best understanding is that latent TB itself is not contagious, but there is a real risk of progression to contagious active TB if it isn’t treated. The other ideas—being contagious all the time, being contagious only with HIV, or being contagious only in hospital—don’t fit, because latent TB isn’t contagious, HIV doesn’t make latent TB contagious (it increases the chance of reactivation), and TB can spread in the community as well as in healthcare settings when it’s active.