TB disease of a small child does not spread, but a school-aged child can have infectious TB disease (TB of the lungs or throat). Young people can easily develop a highly infectious disease.
TB bacteria are spread through the air from one person to another. When a person with infectious TB disease coughs, speaks, or sings TB bacteria spread into the air. Other people who are staying in the same room (flat, classroom, work space, car) may breathe in these bacteria and become infected. People with TB disease are most likely to spread it to people they spend time with every day e.g. people living in the same household.