Georgia ILI Curve

We provide weekly updates from the Georgia Division of Public Health during the flu season, roughly November through March of each year. There is generally a one week lag between data collection and availability to the public. Stay tuned for 2019-2020 updates.

For the complete weekly influenza update from the Georgia Divison of Public Health please click here.

How is this curve constructed?       Each week a group of “sentinel providers” around the country reports to CDC on how many of their patients in emergency departments and clinics have illnesses that match the CDC case definition for “influenza-like illness”, or ILI. ILI is defined as fever PLUS either cough or sore throat that cannot be attributed to another cause such as Strep throat (i.e. Strep throat is NOT an ILI). This data is collected at CDC and posted.

What does the curve mean?     The ILI curve does not tell us the total number of people with flu, it tells us what proportion of patients around the country have an illness like the flu. ILI occurs at a low background rate of 1-2%  throughout the year, even when flu is not circulating. Years of experience has shown that when the ILI curve peaks in the winter, it closely correlates with actual influenza activity as determined by more tedious and expensive viral cultures. Thus, the ILI curve provides a convenient way to track the progress of an influenza outbreak. During the winter (i.e., flu season), most people with ILI actually do have the flu. During the summer and autumn months, patients with ILI almost invariably are infected with other respiratory viruses that are not influenza. The summer of 2009 was a major exception to this rule, reflecting the spread of pandemic flu due to 2009 H1N1 during the US summer months.


Past Updates