Additional file 2 of Detecting signals of seasonal influenza severity through age dynamics

Historical CDC documentation of past influenza seasons. Table of qualitatively-assigned severity categories and surveillance system text descriptions drawn from Centers for Disease Control and Prevention (CDC) influenza season summaries and Morbidity and Mortality Weekly Reports (MMWR) for the 1997–98 through 2013–14 flu seasons. Severity categories were assigned according to the algorithm described in Additional file 1: Supporting material section S3.1. (XLSX 23 kb)