Chronic hepatitis B is contagious, but contagiousness is closely related to disease status. Chronic hepatitis B refers to people who have a previous history of hepatitis B or have been HBsAg positive for more than 6 months and are now still positive for HBsAg and/or HBV-DNA. Chronic hepatitis B is mainly transmitted through the following ways: 1. mother-to-child transmission: This refers to the transmission of the virus from a hepatitis B virus-positive mother to her fetus or newborn during pregnancy, childbirth and breastfeeding; 2. blood transmission: The blood of an infected person has a high level of hepatitis B virus, and a tiny amount of blood entering a susceptible person can cause infection, such as blood and blood products transfusion, surgery, being stabbed by a needle, sharing a razor or toothbrush with a virus-infected person The transmission can be caused by hemodialysis and organ transplantation. In recent years, with the popularity of disposable injection supplies and strict quarantine of blood products, the number of people infected with hepatitis B virus through this route has decreased year by year; 3. Sexual contact transmission: refers to unprotected sexual contact with an infected person who is positive for hepatitis B virus, resulting in the transmission of the virus.