This is the place to look for important information about how to use this dataset, so please expand this box and read on!

This is the source data for some of the metrics available at https://www.chicago.gov/city/en/sites/covid-19/home/reopening-chicago.html#reopeningmetrics.

For all datasets related to COVID-19, see https://data.cityofchicago.org/browse?limitTo=datasets&sortBy=alpha&tags=covid-19.

The National Syndromic Surveillance Program (NSSP), a collaboration among CDC, federal partners, local and state health departments, and academic and private sector partners, is used to capture Emergency Department (ED) visits for COVID-19-Like illness (CLI). CLI is defined as fever and cough or shortness of breath or difficulty breathing or the presence of a coronavirus diagnosis code. Visits meeting the CLI definition that also have mention of flu or influenza are excluded. ED data are collected before cases are diagnosed or laboratory results are confirmed, providing an early warning system for infections. 

Only Chicago residents who visit any hospital in Illinois are included. Residency is based on the home address as reported by the medical provider.

All data are provisional and subject to change. Information is updated as additional details are received and it is, in fact, very common for recent dates to be incomplete and to be updated as time goes on. At any given time, this dataset reflects visits currently known to Chicago Department of Public Health (CDPH).

Numbers in this dataset may differ from other public sources due to sources used, when data are updated, and similar factors.

Data Source: Illinois Hospital Emergency Departments reporting to CDPH through the National Syndromic Surveillance Project (NSSP)

Daily case counts and percentage of all ED visits for COVID-Like Illness. See the underlying dataset for definitions.

A trailing 60 days is shown by default for ease of reading but this period can be adjusted with the filter to the right.