After taking hepatitis B vaccine, it is normal for the original antibody to drop. It is recommended to re-check the titer of hepatitis B antibody after one month, and if it is lower than 10IU/ml, it is an immunization failure, and it is necessary to consult the physician’s advice to adjust the vaccination program, increase the dosage or change the vaccine manufacturer. Hepatitis B vaccine mainly makes hepatitis B surface antibody positive, hepatitis B surface antibody is a kind of protective antibody, some people’s body of hepatitis B surface antibody may decline with time concentration, and need to re-vaccination of hepatitis B vaccine, after the vaccination of hepatitis B vaccine, the original antibody is cleared, there may be a transient decline, which is a normal situation. About 5%-10% of the people who have been vaccinated with hepatitis B vaccine fail to produce surface antibody, mainly because of the result of the combination of internal and external factors of the organism, among which the specific immune response plays a more important role. Immunization failure is common in people with low immune function such as older age, diabetes, immunosuppressants and HIV infection. You can increase the number of immunization injections to stimulate the immune response, and you can also increase the dosage by injecting 60μg of hepatitis B vaccine to stimulate the production of antibodies. Alternatively, the vaccine can be changed to an imported vaccine from a different manufacturer or species to stimulate an immune response. If the antibody titer is less than 10IU/ml, the vaccination program should be adjusted. Hepatitis B vaccine generally needs to be vaccinated three times, in accordance with the regular injection pattern of 0, 1, 6 for hepatitis B vaccine, if the vaccination is not carried out on time, there is a possibility that the antibody titer does not reach the required level, and it is recommended to receive the vaccine on time.