A 41-year-old woman with a positive hepatitis B surface antibody and negative surface antigen is most likely?

The presence of a positive hepatitis B surface antibody (anti-HBs) alongside a negative hepatitis B surface antigen (HBsAg) indicates that the individual has been exposed to the hepatitis B virus (HBV) in the past, but is not currently infected. The surface antibody signifies immunity, which can be a result of prior natural infection or successful vaccination.

In this case, while it is possible for the woman to be immune due to natural infection, the clear marker of not having the surface antigen suggests that there is no active infection at this time. Vaccination would also result in a positive anti-HBs, but the question does not provide additional details to definitively distinguish between these pathways to immunity. However, since the question states the scenario designed for determining immunity based on the serological profile, the most accurate conclusion here is that she is immune to hepatitis B due to a prior natural infection.

This person's profile would not suggest an active infection (which would be indicated by a positive HBsAg) nor would it indicate immediate vaccination responses. Thus, the interpretation of her serological markers aligns most with natural immunity developed from a past infection.