Which serological marker indicates natural immunity to Hepatitis B?

Natural immunity to Hepatitis B is indicated by the presence of Anti-HBs in the serum. This serological marker reflects the body’s immune response to the virus, either from past infection or from vaccination. Specifically, Anti-HBs signifies that the immune system has produced antibodies that can neutralize the Hepatitis B virus, providing protective immunity.

The presence of Anti-HBc implies past or recent infection with Hepatitis B, as it indicates the presence of antibodies generated against the core antigen of the virus. While Anti-HBc can suggest previous exposure, it does not specifically confirm immunity. In contrast, other markers such as HBsAg signify an active infection and HBeAg is associated with viral replication and high infectivity. Therefore, Anti-HBs is the key marker that confirms immunity to Hepatitis B.