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Significant sexual exposure to acute hepatitis B in a documented vaccine non-responder — MSRA MCQ

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HardInfectious DiseasesSignificant sexual exposure to acute hepatitis B in a documented vaccine non-responderMSRA

A 29-year-old healthcare assistant attends her GP surgery 6 days after condomless vaginal intercourse with her regular partner. He was admitted yesterday with jaundice and has acute hepatitis B confirmed (HBsAg positive and anti-HBc IgM positive). She is asymptomatic. She completed a standard 3-dose hepatitis B vaccination course before starting work 4 years ago. Her occupational-health record documents an anti-HBs concentration of 6 mIU/mL measured 6 weeks after the final dose; she received no further doses. She has not previously had hepatitis B infection. What is the most appropriate management today?

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Correct answer: C — Arrange urgent hepatitis B immunoglobulin and a hepatitis B vaccine booster, with sexual-health assessment

This patient is a documented hepatitis B vaccine non-responder: anti-HBs was below 10 mIU/mL when measured 1–2 months after a completed primary course. Her exposure was significant (condomless sexual exposure) and the source has acute hepatitis B, which is highly infectious. Crucially, she presents within 1 week of the last sexual contact. UK guidance advises that sexual contacts of people with acute hepatitis B seen within this period should receive both hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine. HBIG provides immediate passive protection while vaccination is intended to generate active immunity. A would be appropriate for someone who had completed vaccination and was not a documented non-responder, but is insufficient here. C omits vaccination and unnecessarily delays active immunisation; HBIG plus vaccine should be arranged without waiting for HBV DNA. D risks missing the time-limited window for HBIG and should not delay indicated prophylaxis. E incorrectly treats prior vaccination as adequate protection despite documented failure to mount a protective antibody response. Sexual-health assessment is also appropriate because concurrent sexually transmitted infections should be assessed, but it must accompany rather than replace hepatitis B prophylaxis.

Reference: Hepatitis B immunoglobulin (issued November 2023) — post-exposure recommendations (Updated 16 July 2026) — https://www.gov.uk/government/publications/immunoglobulin-when-to-use/hepatitis-b-immunoglobulin-issued-march-2021 Hepatitis B: clinical and public health management (Updated 15 July 2025) — https://www.gov.uk/guidance/hepatitis-b-clinical-and-public-health-management