A patient is Hepatitis B surface antigen (HBsAg) negative, Hepatitis B surface antibody (anti-HBs) positive,...

The Certification Study Guide (6th edition) explains that interpretation of hepatitis B serologic markers is a fundamental competency for infection preventionists, particularly in occupational health and exposure management. In this scenario, the patient is HBsAg negative, indicating no current hepatitis B infection; anti-HBs positive, indicating immunity; and anti-HBc negative, meaning there has been no prior natural infection with hepatitis B virus.

This specific serologic pattern is diagnostic of immunity due to vaccination. The hepatitis B vaccine contains only purified hepatitis B surface antigen, not core antigen. As a result, vaccinated individuals develop antibodies to the surface antigen (anti-HBs) but do not develop antibodies to the core antigen (anti-HBc). The study guide emphasizes this distinction as the key factor in differentiating vaccine-induced immunity from immunity due to past infection.

The incorrect options reflect different serologic patterns. Previous hepatitis B infection would produce a positive anti-HBc result. A recent blood transfusion does not confer long-term immunity or this marker pattern. Low-level infectivity would require detectable surface antigen or core antibody.

This question reflects a classic CIC exam topic: recognizing the serologic profile of vaccine-induced immunity. Correct interpretation supports appropriate employee health decisions, post-exposure management, and immunization program evaluation.