How TB Spreads and Incubates

The risk of being infected given that you've been exposed to somebody with TB is largely dependent on the infector, the person who has TB. The bigger cavities they have, the more infectious they are because those cavities are filled with TB bacilli. When they cough, talk, sing, they aerosolize the bacilli and the people around them are exposed. It's anywhere from less than one, meaning not particularly infectious, to as high as something likesomething like 12.