<prompt> A 33-year-old man has never been vaccinated for hepatitis B. Serologic tests reveal negative hepatitis B surface antigen HBsAg and positive antibody to surface antigen. Which of the following conditions does this serologic pattern best fit with?previous hepatitis B infectionchronic active hepatitisacute hepatitis B infectionpoor prognosis  <response>: The antibody can be demonstrated in 80-90 of patients, usually late in convalescence, and indicates relative or absolute immunity. In contrast, HBsAg occurs very early and disappears in 6 months. Persistence of HBsAg indicates chronic infection. The pattern in this patient is also seen postvaccination, and perhaps as a consequence of remote infection. 