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Pertussis exposure in late pregnancy — MSRA MCQ

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HardInfectious DiseasesPertussis exposure in late pregnancyMSRA

A 31-year-old woman who is 34 weeks pregnant asks for advice. Her husband has PCR-confirmed pertussis; his cough began 10 days ago and he started clarithromycin yesterday. They share a bedroom and she last had close contact with him this morning. She is asymptomatic. She received a pertussis-containing vaccine through the maternal immunisation programme 5 days ago. She has no drug allergies, takes no regular medication, and has no relevant cardiac history. What is the most appropriate management today?

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

Reveal the answer and explanation

Correct answer: D — Prescribe erythromycin 500 mg every 6 hours for 7 days without further pertussis vaccination today

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

She is a household close contact of a case whose cough began within the preceding 21 days. Although maternal pertussis vaccination is the principal preventive measure, she received it only 5 days ago. Pregnant women at 32 weeks’ gestation or later are a priority group for public-health action if they have not received a pertussis-containing vaccine within 5 years, or if they received it within the preceding week. The latter exception applies here: vaccination so recently does not remove the indication for chemoprophylaxis. For pregnant contacts meeting criteria, erythromycin is the preferred antimicrobial. The adult regimen is 500 mg every 6 hours for 7 days. A further pertussis vaccine dose is not indicated, as she has already received the recommended vaccine in this pregnancy. A is incorrect because another vaccine dose neither provides useful immediate post-exposure management nor replaces indicated prophylaxis. C and D are recognised alternative macrolide regimens for adults, but erythromycin is specifically preferred in pregnancy. E would be appropriate if the index cough onset were more than 21 days ago, if exposure were not close/prolonged, or if she had received her pertussis vaccine more than 1 week previously and within the last 5 years.

Reference: National pertussis guidance for England — definitions of priority groups (May 2026) — https://assets.publishing.service.gov.uk/media/66c4a642808b8c0aa08fa7e7/UKHSA-guidance-on-the-management-of-cases-of-pertussis-during-high-activity-august-2024.pdf National pertussis guidance for England — management of close contacts and post-exposure prophylaxis (May 2026) — https://assets.publishing.service.gov.uk/media/66c4a642808b8c0aa08fa7e7/UKHSA-guidance-on-the-management-of-cases-of-pertussis-during-high-activity-august-2024.pdf National pertussis guidance for England — antibiotic treatment and chemoprophylaxis recommendations (May 2026) — https://assets.publishing.service.gov.uk/media/66c4a642808b8c0aa08fa7e7/UKHSA-guidance-on-the-management-of-cases-of-pertussis-during-high-activity-august-2024.pdf