You are in the Emergency Department to admit a 76 year old woman with pneumonia. The patient reports one week of progressive cough, yellow sputum production, fatigue, and eventually shortness of breath and fever. A chest x-ray obtained by the ED staff revealed a right lower lobe infiltrate. She was diagnosed with community acquired pneumonia and is being admitted for oxygen, antibiotics, and supportive care. Armed with all of this information (obtained from the chart) and the certainty that you know how to treat pneumonia, you go to the bedside. After you ask her a few confirmatory questions, she says to you "I had the pneumonia vaccine last year...how can I get pneumonia?" You finish the history and physical, and head off to write your orders.