The fifth positive hepatitis B half-pair (i.e., hepatitis B core antibody) is not a reason for vaccination. Hepatitis B two half of the fifth positive (i.e., hepatitis B core antibody), the other four (i.e., hepatitis B surface antigen, hepatitis B surface antibody, hepatitis B e antigen, hepatitis B e antibody) are negative, indicating that there are two possibilities, the first is now infected with the hepatitis B virus and in the acute phase of the hepatitis B virus, in this case, do not advocate the hepatitis B vaccine, it is recommended that the first hospital for the examination of liver function, hepatitis B virus DNA. It is recommended to go to the hospital for liver function and hepatitis B virus DNA examination first. In the second case, if you have been infected with hepatitis B virus, but now you have recovered and are not infectious, but you do not have protective antibody (hepatitis B surface antibody), you can get hepatitis B vaccine. Therefore, positive hepatitis B core antibody is not due to vaccination, but may be caused by current or former hepatitis B virus infection, and after hepatitis B vaccination, the second half of hepatitis B (hepatitis B surface antibody) will be positive, of course, there are a small number of people who will not have positive hepatitis B surface antibody even after hepatitis B vaccination. If the fifth item of Hepatitis B two halves (Hepatitis B core antibody) is positive, it is recommended to go to the hospital for examination and treatment.