The reason why hepatitis B vaccine can no longer be administered in the case of hepatitis B minor third-positive is because the body does not produce hepatitis B surface antibodies. The hepatitis B vaccine itself is inactivated hepatitis B virus surface antigen, so the body can produce protective antibodies through active immunity by means of intramuscular injection of hepatitis B vaccine. Patients with hepatitis B virus already exist in their bodies, so if they receive the hepatitis B vaccine again, the original strain of hepatitis B virus may mutate or disrupt their immune system and produce hepatitis. In addition, intramuscular injection of hepatitis B vaccine does not stimulate the immune system to produce surface antibodies to hepatitis B. Therefore, as mentioned above, the hepatitis B vaccine is not available to those who already have hepatitis B minor triple-positive, and it will not do any good to the body.