The incidence of viral hepatitis in China has always been among the top of all infectious diseases, and the incidence of hepatitis C in viral hepatitis has increased significantly. The main transmission routes of hepatitis C (HCV) are: 1. Mainly transmitted by blood (1) transmitted by blood transfusion and blood products. This route has been effectively controlled since 1993, when blood donors were screened for anti-HCV. However, due to the window period of anti-HCV, the unstable quality of anti-HCV testing reagents and the fact that a small number of infected patients do not produce anti-HCV, it is impossible to completely screen out HCV RNA-positive people, and a large number of blood transfusions and hemodialysis may still infect HCV. (2) Transmission through broken skin and mucous membranes. This is by far the predominant mode of transmission, with HCV transmission due to intravenous drug use accounting for 60% to 90% of transmission in some areas. The use of non-disposable syringes and needles, non-sterile dental instruments, endoscopy, invasive procedures and needlesticks are also important routes of transdermal and mucosal transmission. Some traditional medical practices that may lead to skin breakdown and blood exposure are also associated with HCV transmission; sharing razors, toothbrushes, tattoos, and ear piercing are also potential modes of HCV transmission via blood. 2.Sexual transmission: The risk of HCV infection is higher for those who have sexual intercourse with HCV-infected persons and those who have sexual promiscuity. People with other sexually transmitted diseases, especially those infected with human immunodeficiency virus (HIV), have a higher risk of HCV infection. The risk of mother-to-child transmission: The risk of HCV transmission from an anti-HCV-positive mother to her newborn is 2%, but if the mother is positive for HCV RNA at the time of delivery, the risk of transmission can be as high as 4% to 7%; when combined with HIV infection, the risk of transmission increases to 20%. high HCV viral load may increase the risk of transmission. 4. The transmission route of some HCV infected patients is unknown. HCV is not transmitted by kissing, hugging, sneezing, coughing, food, drinking water, sharing utensils and glasses, no skin break and other non-blood exposure. HCV RNA can be detected in peripheral blood 1 to 3 weeks after exposure to HCV, but only 50% to 70% of patients are anti-HCV positive when clinical symptoms appear in acute HCV infected patients, and about 90% of patients are anti-HCV positive after 3 months. After 3 months, about 90% of patients have positive anti-HCV.