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HIV — SCE Infectious Diseases MCQ

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HardHIV MedicineHIVSCE Infectious Diseases

An asymptomatic household contact of probable toxigenic respiratory diphtheria is fully vaccinated. What public-health intervention remains appropriate while reference testing proceeds?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: E — Give antibiotic prophylaxis and indicated vaccine; reserve antitoxin for clinical disease

Explanation lettering: C = shown as A · A = shown as B · E = shown as C · B = shown as D · D = shown as E

D is correct. Diphtheria vaccination protects strongly against toxin-mediated disease but does not reliably prevent carriage. Close contacts therefore need urgent Health Protection Team risk assessment, antibiotic prophylaxis and vaccination or boosting as indicated. Diphtheria antitoxin neutralises circulating toxin in suspected clinical disease and is not contact prophylaxis. Waiting for final toxigenicity can permit transmission, while isolation alone does not eradicate nasopharyngeal carriage.

Reference: UKHSA: diphtheria public-health control and management: https://www.gov.uk/government/publications/diphtheria-public-health-control-and-management-in-england-and-wales