Hepatitis B is known clinically as chronic hepatitis B. It is mainly caused by infection with the hepatitis B virus, or hepatitis B for short. Normal healthy people do not self-generate this virus, but are mostly infected with it because the hepatitis B virus is transmitted to the body and their own immunity is low. The main routes of infection for normal people are contact transmission, blood transmission, sexual transmission, mother-to-child transmission and transmission in health care settings. 1. Contact transmission: contact with the blood and body fluids of a virus carrier or hepatitis B infected person through the skin can be transmitted through small skin lesions or skin mucous membranes. The common use of toothbrushes, razors, cutlery, etc. with hepatitis B patients may be infected; 2, blood transmission: blood with the hepatitis B virus in the blood transfusion input, or with hepatitis B virus carriers, hepatitis B patients share a needle for intravenous injection, as well as sharing a needle tattoo, acupuncture, ear piercing, etc., can lead to infection; 3, sexual transmission: mainly through body fluids for transmission, if the number of sexual partners If the number of sexual partners is too many, or have sex with unfamiliar partners, it is easy to increase the risk of infection with hepatitis B virus; 4. Mother-to-child transmission: When the placenta of a pregnant woman is close to maturity or mature, if the body itself contains hepatitis B virus, it may lead to fetal infection through the placenta. And during delivery, if the newborn has a skin lesion condition, while this part is in close contact with the mother’s blood, amniotic fluid, etc., it may cause infection, which may also occur after delivery; 5. Transmission from health care settings: It mainly occurs between patients and patients, or between patients and medical care. Since hospitals have more patients, when disinfection is not in place, the spread of infection can easily occur.