USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 61-year-old man comes to the clinic because of sinus congestion, dyspnea, fatigue, and productive cough. He says that he received his annual influenza vaccine approximately two months ago, and was in otherwise good health prior to this recent onset of symptoms. Chest X-ray shows mild, bilateral patchy infiltrate. Sputum culture shows no gram-staining organisms, and a test for cold agglutinins is negative. Which of the following is the most likely cause of the patient’s symptoms?