What is an ILI percentage?
ILI stands for influenza-like illness. Public health agencies like the U.S Centers for Disease Control track the percentage of doctor visits each week which are related to ILI, gathering data from a network of sentinel healthcare providers. A high ILI percentage means that a large fraction of patients are experiencing influenza-like symptoms. These symptoms are often caused by seasonal influenza viruses, but other viruses can also cause influenza-like symptoms. A notable increase in ILI-related doctor visits may indicate a need for a public health inquiry to identify the pathogen or pathogens involved.
