What is the significance of a hepatitis B half-check and finding only one positive core antibody? Anti-HBc positive, there may be five conditions: The first is an indicator of acute (recent) infection. Anti-HBc is the antibody produced corresponding to the core antigen of hepatitis B virus (HBcAg) and can be divided into two types: namely, anti-HBcIgM type and anti-HBcIgG type. The earliest to appear after HBV infection is the anti-HBcIgM type, which is the (or recent) sign of acute HBV infection. 3-5 weeks after the appearance of HBsAg, anti-HBcIgM appears, and later transforms into anti-HBcIgG. When HBsAg disappears after acute infection, but anti-HBs has not yet appeared, only anti-HBc can be detected in the blood, which is medically known as “window period”, which is meaningful for the diagnosis of acute hepatitis B. The second condition is an indicator of previous hepatitis B virus infection. It indicates that the hepatitis B virus infection has been clinically recovered, and the blood should be stocked with anti-HBcIgG (but the two-and-a-half pairs checked in general hospitals are total antibodies including anti-HBcIgM and anti-HBcIgG, and the two cannot be distinguished). The third condition is anti-HBc that may be acquired passively, such as by blood transfusion, or by a newborn born to an AoA-positive mother whose blood is passed on by confusion with the newborn’s blood, and which can persist for more than a year. The fourth case is when the patient is still positive for HBsAg, but the kit is not sensitive and fails to detect it because it is at a low level. The last case is a false positive due to laboratory error. Do I need to get vaccinated again if I am positive for hepatitis B surface antibody and have never been vaccinated before? If a person who has never received the hepatitis B vaccine before is found to have positive hepatitis B surface antibodies, it means that hepatitis B virus infection has already occurred in the past and protective antibodies have been produced, so such a person does not need to receive the hepatitis B vaccine again. However, if vaccinated, there are no adverse reactions that can increase the original anti-HBs level. For patients who have developed antibodies from natural infection, they should be traced intermittently. Because those who have produced antibodies after vaccination, their antibody levels will gradually decline, but within 10 years, they can still generally reach the level that protects the organism from infection. If antibodies change from positive to negative, further booster injections are required.