Hepatitis B core antibody is one of the five tests for hepatitis B. A positive test means that you have been infected with hepatitis B. Only when you have been infected with the hepatitis B virus is it possible for your body to produce the corresponding core antibodies. If you have only received the hepatitis B vaccine and have not been infected with the hepatitis B virus, it is impossible for your body to produce core antibodies because the antigen corresponding to this antibody, called the core antigen of hepatitis B, exists only in the hepatitis B virus and not in the hepatitis B vaccine. If you are positive for hepatitis B core antibodies alone, you have not been previously vaccinated for hepatitis B, and you do not have a history of hepatitis B infection, it is sometimes possible that the test is incorrect.