Viral hepatitis is a group of infectious diseases caused by hepatitis virus and characterized by liver damage. Viral hepatitis is highly infectious, with complex transmission routes, wide prevalence and high incidence. Viral hepatitis should be detected early, diagnosed early, isolated early, reported early, treated early and handled early to prevent epidemics. Wei Ping, Department of Infection, Wuhan Union Medical College Hospital There are five known types of hepatitis A, B, C, D and E viruses. Hepatitis caused by these five types of hepatitis viruses are accordingly called viral hepatitis A (hepatitis A), viral hepatitis B (hepatitis B), viral hepatitis C (hepatitis C), viral hepatitis D (hepatitis D), and viral hepatitis E (hepatitis E), and hepatitis D virus can only be infected at the same time as or on the basis of hepatitis B virus infection. The source of infection for viral hepatitis is a person with hepatitis or an asymptomatic carrier of the virus. There are two ways of transmission: one is mainly through the gastrointestinal tract, such as type A and type E; the other is mainly through blood and body fluids, including vertical transmission from mother to child, medical transmission (such as the use of unclean medical devices, blood or blood products transfusion, etc.) and sexual transmission, such as type B, type C and type D. Humans are generally susceptible to all types of hepatitis and can develop at all ages. Hepatitis A mainly affects children and adolescents, and the peak season of hepatitis A is often in winter and spring. The epidemiological characteristics of hepatitis E are similar to those of hepatitis A. Hepatitis B, C and D do not have a certain epidemic period and can occur throughout the year, but are mostly disseminated. The clinical manifestations of viral hepatitis are mainly weakness, loss of appetite, nausea, vomiting, hepatomegaly and liver function abnormalities, and some patients may have jaundice and fever. Hepatitis A presents as an acute infection with a self-limiting course, without chronicity, and severe disease is extremely rare. Hepatitis E has similar clinical symptoms to hepatitis A, but is more severe than hepatitis A. It can develop into acute severe hepatitis (acute liver failure), especially in pregnant women, the elderly, and those with underlying liver disease. Most of the cases of hepatitis B, C and D have a chronic course, and a few cases can develop into severe hepatitis, cirrhosis and liver cancer. Hepatitis A and E have a self-limiting course and are treated mainly with general and supportive therapy, supplemented by appropriate medications and avoiding alcohol, fatigue and liver-damaging drugs. The most effective treatment for hepatitis B and C is antiviral therapy, the goal of which is to maximize long-term suppression or clearance of the virus, delay and reduce the occurrence of liver decompensation, cirrhosis, liver cancer and its complications, thereby improving the quality of life and prolonging the survival time of patients. Prevention of viral hepatitis: 1. Vaccine is the first choice for the prevention of hepatitis B. Hepatitis B vaccination is the safest and most effective measure to prevent hepatitis B. After the full course of hepatitis B vaccination, about 80%-95% of the population can develop immunity, and the protective effect can last for more than 20 years. Three doses of hepatitis B vaccine should be administered at 0, 1 and 6 months. The first dose should be given within 24 hours of birth, and the full course of vaccination should be completed. Hepatitis B vaccine should also be given to medical personnel, people with frequent contact with blood, workers in childcare institutions, frequent recipients of blood transfusions or blood products, family members of people with positive surface antigen for hepatitis B virus, men who have sex with men or multiple sexual partners, and people who inject drugs intravenously, etc. 2. Preventing “disease from the mouth” can prevent hepatitis A and E Virus infection. Hepatitis A and E viruses are mainly transmitted through the digestive tract, so pay attention to diet and water hygiene. Hepatitis A vaccine has been included in the national immunization program, and vaccination against hepatitis A can effectively prevent hepatitis A. The hepatitis E vaccine has been successfully developed and is believed to be used clinically in the near future.3. Cut off the transmission route and prevent hepatitis C. Although hepatitis C cannot be prevented by vaccination, it can be completely prevented by taking effective measures to cut off its transmission route (such as using safe blood products, not sharing syringes, avoiding unclean medical practices, etc.).