Who is considered a person having a close contact with TB infected individual?

Whether a person who has been in contact with someone with open TB will become infected and/or develop TB disease depends on many factors.

People at highest risk of contracting TB are: 

People living in the same household and family members, also people in closed groups (e.g. prisons, shelters for the homeless or migrants, schools, offices and those who have a long-term close contact with a TB patient).

Factors causing a risk of infection and/or disease:

• Exposure time (e.g., 8 hours or more);
• Dose of infection;
• The environment where a contact takes place (the risk is greater in small, closed rooms, rooms with poor ventilation, air recirculation);
• The condition of the patient with tb (e.g., the amount of tm released into the environment, whether the person uses drugs or not);
• The age of the person who had a contact (e.g., child under 5 or an adult);
• Health conditions of the person who had a contact (e.g., immunosuppression, diseases, etc.);
• Properties of mycobacteria (pathogenicity, virulence).