How long it takes to be infected with a TB patient depends on the individual’s immunity, the degree of exposure, the patient’s treatment, and other factors, and cannot be generalized. Not all normal people will be infected after having contact with a TB patient. If a TB patient is undergoing treatment and the contactor has a strong immune system, there is generally no chance of infection with a TB patient in ordinary contact. If a person with tuberculosis is seriously ill and the contact has a reduced immune system, he or she will be susceptible, especially children or the elderly. If the person is often in contact with him or her, or if he or she spits or eats together, it is usually possible for the Mycobacterium tuberculosis bacterium to invade and cause infection in a few or ten days. Since tuberculosis is mainly transmitted through the respiratory tract, it is important to wear a mask when in contact with patients and to keep a certain distance and avoid talking loudly with patients to effectively prevent the transmission of tuberculosis.