mrcem2-1800

A 35-year-old man who resides in a Traveller community comes in with a severe paroxysmal cough and a fever that has persisted for the last 10 days. He reports not having received any vaccinations. A nasopharyngeal swab for pertussis comes back positive. He is currently 18 weeks into his wife’s pregnancy.
What is the most suitable initial antibiotic to prescribe?