In the hepatitis B serology case, which marker indicates a lack of protective immunity against HBV?

In the hepatitis B serology case, which marker indicates a lack of protective immunity against HBV?

• A. Anti-HBs
• B. HBsAg
• C. Anti-HBc
• D. HBeAg

Answer: (A)

The main idea here is that protective immunity to hepatitis B is shown by the presence of antibodies against the surface antigen, Anti-HBs. When Anti-HBs is detectable, you have immunity from vaccination or prior infection. Conversely, a lack of protective immunity would be indicated by the absence of Anti-HBs (no surface antibodies). The other markers reflect infection status or viral activity rather than immunity: HBsAg shows current infection, Anti-HBc shows prior exposure, and HBeAg indicates active viral replication and high infectivity. So, Anti-HBs tells you about immunity when it’s present, and its absence would signal a lack of protective immunity.

The main idea here is that protective immunity to hepatitis B is shown by the presence of antibodies against the surface antigen, Anti-HBs. When Anti-HBs is detectable, you have immunity from vaccination or prior infection. Conversely, a lack of protective immunity would be indicated by the absence of Anti-HBs (no surface antibodies). The other markers reflect infection status or viral activity rather than immunity: HBsAg shows current infection, Anti-HBc shows prior exposure, and HBeAg indicates active viral replication and high infectivity. So, Anti-HBs tells you about immunity when it’s present, and its absence would signal a lack of protective immunity.