Which antibiotic is recommended for plague prophylaxis after exposure?

• A. Amoxicillin for 5 days.
• B. Doxycycline or ciprofloxacin for about 7 days after exposure (or until exposure risk ends).
• C. Penicillin G for 10 days.
• D. Erythromycin for 14 days.

Answer: (B)

Post-exposure prophylaxis for plague aims to protect people who were exposed to a pneumonic plague case from developing the illness. The best choice is doxycycline or ciprofloxacin given for about a week after exposure (or until the exposure risk ends). Doxycycline is preferred because it reliably covers Yersinia pestis, has convenient dosing, and good tissue penetration; ciprofloxacin is a solid alternative when doxycycline isn’t suitable. The other antibiotics listed aren’t recommended for plague prophylaxis because they don’t have reliable activity against Y. pestis, and the durations shown don’t match the recommended window of protection.