A 32-year-old woman seeking to become pregnant visits her physician for a pre-pregnancy examination. Routine prenatal laboratory testing demonstrates the following profile: HBsAg (-), anti-HBsAg (+), anti-HBcAg (-), anti-HBeAg (-), and HBV DNA (-). Which of the following likely represents the status of the patient?

The patient is only positive for antibody to the hepatitis B antigen. This suggests that the patient has been vaccinated for hepatitis B virus (HBV). The vaccine consists of recombinantly produced HBV surface antigen (HBsAg) alone; Antibodies to the core protein (anti-HBcAg) appear during acute illness and between the disappearance of HBsAg and the appearance of anti-HBsAg, the "window period.