Commonly used prophylactic dosing regimens include isoniazid alone, rifampin alone, isoniazid and rifampin in combination, isoniazid and rifapentine in combination, and rifampin and pyrazinamide in combination. The course of medication varies from 3 to 12 months depending on the medication used, and will be made by a professional physician according to the actual situation. When an epidemic of tuberculosis is detected in collective units such as schools and factories, close contacts of the case with skin nodules ≥15mm on PPD skin test results are the priority population for preventive medication. Other priority groups include people who are co-infected with HIV and TB, children in close contact with newly bacteriologically positive patients, newly infected children with no history of exposure, new entrants to environments with high TB infection, such as medical personnel, and patients with long-term immunosuppressive use and diseases that increase the risk of TB development, such as diabetes, pneumoconiosis, and chronic malnutrition.