Are hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc) positive results infectious?

HBsAg and anti-HBc positive results (second and fifth items) typically indicate no infectivity. This result suggests that the individual was previously infected with the hepatitis B virus but has since recovered and developed immunity against it. The detailed analysis is as follows:

In the five-item hepatitis B panel, the second item refers to hepatitis B surface antibody (anti-HBs), and the fifth item refers to hepatitis B core antibody (anti-HBc). Anti-HBs is a protective antibody; its presence indicates that the body contains substances capable of defending against the hepatitis B virus, thereby preventing reinfection. A positive anti-HBc only indicates past infection with the hepatitis B virus and does not imply active viral replication at present.

When both markers are positive, it means the body was previously exposed to the hepatitis B virus and the immune system has successfully cleared the virus. There is currently no active hepatitis B virus present in the body, so the person is not infectious. It should be noted that in rare cases, due to hepatitis B virus mutations, there might be low-level viral replication even when anti-HBs is positive. However, this situation is extremely rare and requires confirmation via hepatitis B virus DNA (HBV DNA) testing. If the HBV DNA test is negative, infectivity can be completely ruled out.

Individuals with positive results for the second and fifth hepatitis B markers do not need to worry about transmitting the virus to others and do not require special treatment. It is recommended to periodically check anti-HBs titers. If the titer drops below the protective level, a hepatitis B vaccine booster dose may be administered under medical guidance to maintain long-term immunity.