The main routes of HCV infection are transmission through blood and body fluids. Common transmission routes are as follows: 1. Transmission via blood and blood products Once the most important transmission route, it has been reported that most HCV infections were currently contracted via blood transfusions or blood products from the late 1980s to the mid-1990s. With the strict screening of anti-HCV in blood donations, this mode of transmission has been significantly controlled, but the possibility of transfusion transmission of hepatitis C still exists due to the existence of a window period for anti-HCV, a small number of HCV-infected patients who do not produce anti-HCV or have low anti-HCV titers, and the existing methods cannot completely screen out HCV-infected patients. 2.Transmission through broken skin and mucous membrane Intravenous drug addicts sharing syringes is a common way to get infected with hepatitis C. It is reported that more than 80% of intravenous drug addicts are anti-HCV positive. The sharing of razors, toothbrushes, tattoos and ear piercings are also potential modes of HCV transmission. 3, sexual transmission HCV can be excreted through saliva, semen and vaginal secretions, so sexual contact can cause hepatitis C transmission. However, studies have found that couples with a single sexual partner have a low rate of anti-HCV positivity, while female sex workers, men who have sex with men, and those with multiple sexual partners have a high rate of anti-HCV positivity, and human immunodeficiency virus (HIV)-positive people have a higher rate of anti-HCV positivity in this high-risk sexual behavior. 4.Vertical transmission mainly occurs in intrauterine infection, and the rate of HCV infection in infants is 4-7%, which only occurs in HCV RNA-positive mothers, and the co-infection of HIV in pregnant women can make the incidence of vertical transmission of HCV up to 20%. It is generally believed that vertical transmission is associated with maternal blood HCV RNA load exceeding 106 copies per mL, prolonged labor after rupture of membranes and intrauterine fetal distress, but not with vaginal delivery, cesarean section or breastfeeding. The high-risk groups for HCV infection include: intravenous drug users, professional blood donors, HIV-infected patients, sexually promiscuous patients, those who receive hemodialysis, those who need repeated large transfusions of blood or blood products, and those who are occupationally exposed. For high-risk groups, we should be alert to the possibility of HCV infection, and liver function and anti-HCV tests should be performed during physical examinations to achieve early detection, early diagnosis and early treatment.