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Acute aortic dissection — USMLE Step 3 MCQ

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HardEmergency MedicineAcute aortic dissectionUSMLE Step 3

A 72-year-old immunocompetent woman received PCV13 at age 65 and PPSV23 at age 66. She has received no other pneumococcal vaccine. At a preventive visit 6 years later, she asks whether a newer conjugate vaccine would provide additional protection. After shared decision-making, she prefers vaccination. Which plan is most appropriate?

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Correct answer: D — Administer one dose of PCV20 or PCV21 now

The best answer is “Administer one dose of PCV20 or PCV21 now”. For an adult aged 65 years or older who previously received both PCV13 and PPSV23, with PPSV23 given at or after age 65, CDC permits PCV20 or PCV21 based on shared clinical decision-making when at least 5 years have elapsed since the last pneumococcal vaccine. A further PPSV23 dose is not the completion strategy, and PCV15 would ordinarily require a PPSV23 sequence that this patient has already received. The alternatives are less suitable because they mistime the intervention, omit a necessary component, or apply treatment for a different physiologic problem; the stem's decisive findings determine the sequence.

Reference: CDC Pneumococcal Vaccine Recommendations: https://www.cdc.gov/pneumococcal/hcp/vaccine-recommendations/index.html