Hepatitis C is a disease mainly transmitted through blood. Chronic infection with hepatitis C virus (HCV) can lead to chronic inflammatory necrosis and fibrosis of the liver, and some patients can develop cirrhosis or even hepatocellular carcinoma (HCC), which is extremely dangerous to the health and life of patients and has become a serious social and public health problem. With the support of the Ministry of Health and the leadership of the Chinese Medical Association, the Hepatology and Infectious and Parasitic Diseases Sections of the Chinese Medical Association organized domestic experts to develop guidelines for the prevention and treatment of hepatitis C in China in accordance with the principles of evidence-based medicine and with reference to the latest research results at home and abroad. Hepatitis C is a disease mainly transmitted through blood. Chronic infection with hepatitis C virus (HCV) can lead to chronic inflammatory necrosis and fibrosis of the liver, and some patients can develop cirrhosis or even hepatocellular carcinoma (HCC), which is extremely harmful to the health and lives of patients and has become a serious social and public health problem. With the support of the relevant leaders of the Ministry of Health and the Chinese Medical Association, the Hepatology Branch and the Infectious and Parasitic Diseases Branch of the Chinese Medical Association organized relevant domestic experts to develop guidelines for the prevention and treatment of hepatitis C in China in accordance with the principles of evidence-based medicine and with reference to the latest research results at home and abroad. It must be noted that the essence of clinical medicine lies in taking the most reasonable diagnostic and treatment measures according to the specific situation of the patient and the available medical resources. Therefore, this guideline should not be regarded as a set-in-stone golden rule. The development of modern medicine is changing rapidly, and new theories, new ideas, new diagnostic techniques, and new prevention and treatment methods will continue to emerge, and this guideline will be revised and updated periodically according to the latest clinical medical evidence. I. Pathogenesis of hepatitis C (a) HCV characteristics HCV belongs to the flaviviridae family, its genome is single-stranded positive-stranded RNA, easily mutated, and can be divided into six genotypes and different subtypes, according to the internationally accepted method, the HCV genotype is indicated by Arabic numerals, and the genetic subtypes are indicated by lowercase letters (such as 1a, 2b, 3c, etc.). Genotype 1 is globally distributed, accounting for more than 70% of all HCV infections, and after a certain period of time, a cluster of related mutant strains, mainly a dominant strain, is formed in the infected person, called quasispecies. (B) HCV genome structural features The HCV genome contains an open reading frame (ORF), encoding more than 10 structural and non-structural (NS) proteins; NS3 protein is a multifunctional protein with protease activity at the amino terminus and helicase/nucleoside triphosphate activity at the carboxyl terminus; NS5B protein is an RNA-dependent RNA polymerase, both of which are essential for HCV replication and are important targets for antiviral therapy. NS5B protein is an RNA-dependent RNA polymerase, which is necessary for HCV replication and is an important target for antiviral therapy. (C) HCV inactivation methods HCV is sensitive to general chemical disinfectants; 100 ℃ for 5 min or 60 ℃ for 10 h, high-pressure steam and formaldehyde fumigation can inactivate the virus. Second, the epidemiology of hepatitis C (a) the world’s hepatitis C epidemic hepatitis C is globally prevalent, is the most important cause of end-stage liver disease in Europe, the United States and Japan and other countries. According to the World Health Organization, the global infection rate of HCV is about 3%, and it is estimated that about 170 million people are infected with HCV, with about 35,000 new cases of hepatitis C each year. (B) China’s hepatitis C epidemic status national seroepidemiological survey data show that China’s general population anti-HCV positive rate is 3.2%. The anti-HCV positivity rate varies somewhat from place to place, with the Yangtze River as the boundary, and is higher in the north (3.6%) than in the south (2.9%), and 2.5%, 2.7%, 3.2%, 3.3%, 3.8% and 4.6% in southwest, east, north, northwest, south-central and northeast China, respectively. The anti-HCV positivity rate gradually increased with age, from 2.0% in the 1-year-old group to 3.9% in the 50-59-year-old group. HCV genotypes 1b and 2a are more common in China, with type 1b predominant; types 1a, 2b and 3b have been reported in some areas; type 6 is mainly found in Hong Kong and Macau, and can also be seen in the southern border provinces. (C) hepatitis C transmission routes 1. HCV is mainly transmitted by blood, mainly: (1) transmitted by blood transfusion and blood products. This route has been effectively controlled since 1993 when blood donors were screened for anti-HCV in China. However, due to the existence of 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 there is still a possibility of HCV infection through massive blood transfusion and hemodialysis.(2) Transmission through broken skin and mucous membranes. This is by far the predominant mode of transmission, and in some areas, HCV transmission due to intravenous drug use accounts for 60% to 90%. The use of non-disposable syringes and needles, dental instruments not strictly sterilized, endoscopy, invasive procedures and needle sticks 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 transmural transmission of HCV.