There is no clear conclusion on how long it takes for hepatitis B antibodies to disappear in children, and it is generally believed that hepatitis B antibodies may persist for at least 30 years after children receive the full course of hepatitis B vaccine as part of the basic immunization process. Hepatitis B vaccine belongs to the National Class I Immunization Vaccine, which is a basic vaccine provided by the state free of charge, mainly for the prevention of hepatitis B disease. The vaccination program for children is three shots, i.e. at birth, one month and six months. After vaccination, hepatitis B antibodies will be formed in the body, and it is currently believed that the validity of these antibodies in the body will last for at least 30 years. Parents are advised to vaccinate their children with hepatitis B vaccine and other basic immunization vaccines in a timely manner under the guidance of a doctor after birth to help the children’s bodies form the corresponding antibodies, which can prevent the corresponding infectious diseases and promote the healthy growth of the children. If there is any discomfort, please consult a doctor in time.