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HBV Vaccination Immunity — RACP Adult Medicine MCQ

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EasyInfectious DiseasesHBV Vaccination ImmunityRACP Adult Medicine

A 30-year-old healthcare worker has hepatitis B serology: HBsAg negative, anti-HBs positive (>100 mIU/mL), anti-HBc negative, HBeAg negative. What is the most likely interpretation?

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Correct answer: DImmunity from vaccination

HBsAg negative + anti-HBs positive (>10 mIU/mL) + anti-HBc negative = immunity from vaccination. Anti-HBc is the key differentiator: negative anti-HBc means no prior infection (only vaccination produces isolated anti-HBs without anti-HBc). Anti-HBs >100 mIU/mL indicates robust vaccine response. No further doses needed.

Reference: GESA – 2022 – Hepatitis B; Australian Immunisation Handbook 2024