Tuberculosis is an infectious disease, but not all people get it. Who is more likely to get TB? What conditions make you more likely to get TB? Studies have shown that the susceptibility to tuberculosis is mainly related to the amount and duration of exposure to the bacillus, the virulence of the bacteria, the immunity of the body and the sensitivity to the bacillus. The more and longer the exposure to Mycobacterium tuberculosis, the lower the immunity of the body, the more likely it is to get tuberculosis. These susceptible groups are divided into four categories: 1. Close contacts of infectious TB patients: Close contacts of Tu-Yang TB are a very definite high-risk group for TB, with a higher rate of infection and morbidity compared to the general population. This includes family members living together, colleagues in the same office, classmates in the same dormitory, and also people who stay together in a closed space (e.g., an airplane) for a certain length of time (usually more than 8 hours). 2. People with low immunity: People with low immunity have low immunity to Mycobacterium tuberculosis. Common causes and groups of people with low immunity include: ① people with immunodeficiency diseases, those infected with HIV; ② patients with various critical illnesses, such as heart failure, liver and kidney failure; ③ patients receiving radiotherapy and chemotherapy; ④ patients taking corticosteroids for a long time; ⑤ patients with pre-existing serious lung lesions, such as silicosis and pneumoconiosis; ⑥ elderly people with degenerative body functions. 3.People who have never been exposed to TB bacilli: People who have never been exposed to TB bacilli or never received BCG vaccination often lack resistance to TB bacilli, and this group often includes infants and children under 5 years old, children and adolescents from remote mountainous areas (such as Tibet and Xinjiang), etc. 4. People who are likely to be repeatedly exposed to TB patients for a long time: This mainly includes medical personnel, especially those in respiratory outpatient clinics and respiratory wards in comprehensive medical institutions. Since potential TB patients often visit these departments before being diagnosed, these patients are likely to be patients who are already excretors of TB bacteria.