How is tuberculosis spread?
TB spreads from one person to another when someone who is sick with TB coughs germs into the air. The TB germs can live in the air for hours.
People who are sick with TB in their lungs can spread the germs to others. When women are sick with TB, it may spread to their children and others they take care of every day. People who are infected with TB but not sick with signs of TB, and those who are sick with TB in other parts of the body, are not contagious.
If not treated correctly, a person sick with TB will infect about 10 more people with TB each year. But once a person has been taking medicines for about a month, he or she is probably no longer contagious.