Because the epidemiology of pneumonia is changing, we performed an updated, population-based analysis of hospitalization and case-fatality rates for pneumonia patients in the United States. From 2002 to 2011, hospitalization rates decreased significantly for pneumonia caused by pneumococcus and Haemophilus influenzae but increased significantly for Pseudomonas spp., Staphylococcus aureus, and influenza virus.
Trends in Pneumonia Mortality Rates and Hospitalizations by Organism, United States, 2002-2011(1).