The likelihood of developing chronic infection after hepatitis B virus infection depends on the age at which the infection occurs, with hepatitis B virus infection within 6 years of age being the most likely to develop into chronic infection. More than 90% of healthy adults infected with the hepatitis B virus will recover on their own within a year, and the likelihood of developing a chronic infection is less than 5%. The transmission of hepatitis B includes: 1. Mother-to-child transmission: It is the main cause of hepatitis B virus infection in China. Mothers with acute hepatitis B and those carrying HBsAg are at risk of transmitting hepatitis B to their newborns. The essence of this transmission is transmission through the blood route. 2. Blood transmission: This includes the importation of blood and blood products containing hepatitis B virus, unclean injections, surgery, dental extractions, tattoos, acupuncture, ear piercing, endoscopy and accidental stab wounds by medical personnel. Transmission of hepatitis B from blood transfusions is now rare due to enhanced screening of blood donors. However, a small number of HBVDNA-positive, but hepatitis B virus surface antigen (HBsAg)-negative blood may still be missed. Therefore, the transmission of hepatitis B through the blood route has not been completely eliminated. 3, medical transmission: mainly due to the use of non-disposable syringes and endoscopes that have not been strictly sterilized. Therefore, disposable medical devices should be vigorously promoted. Now the country is the disinfection of endoscopes to develop more stringent sterilization norms, this move can greatly reduce the transmission of medical sources. 4, sexual transmission: the rate of HBsAg positivity of sexual transmission is 5.44%, while the rate of HBsAg positivity of general contact transmission in social life is only 0.68%. Therefore, in the family, HBsAg-positive spouses are more likely to be infected with hepatitis B than other family members. Sexual promiscuity is one of the causes of sexual transmission of hepatitis B. 5, contact transmission in daily life: such as sharing razors, toothbrushes and other hygiene products. Or wound-to-wound contact.