Of 58,258 cases reported,* we are aware of 7,706 (13.2%) hospitalized** cases; 2,307 (4.0%) have been hospitalized in the intensive care unit. *Based on previous experience with reportable diseases, cases with unknown hospitalization status are more likely to be mild cases. **Hospitalization status refers to whether cases were ever hospitalized, not current hospitalization status.

*Includes tests performed by labs participating in electronic laboratory reporting. Does not include serology (antibody) tests. Values will differ from metrics reported by IDPH due to factors such as different jurisdictional boundaries. Indeterminate results are excluded from percent positivity calculations but not from total numbers displayed. **People who have been tested multiple times are only counted once. For individuals with all positive or all negative results, the earliest specimen is included. For individuals with mixed results, the earliest positive specimen is included.

All rates are calculated with populations from the 2010 United States Census. Counts between 1 and 4 are supressed to protect patient privacy. *Weekly counts and rates are updated every Wednesday and represent cases reported the previous Sunday through Saturday. **Percent change is calculated by comparing counts from the past 14 days to the 14 days preceding that. Percent change is not calculated if there were 1-4 cases in the past 14 days or in the 14 days preceding that. A 14 day period is used, rather than 7 day period, to reduce the impact of minor fluctuations in the data. The most recent data that goes into calculating percent change may not yet be displayed in the Trends in COVID-19 Rates graph.

In addition to confirmed case counts, health departments will often monitor disease trends using information collected before an official diagnosis is made - such as the symptoms a patient reports to their doctor. This is called syndromic surveillance. While it is not as precise as counting confirmed cases, syndromic surveillance can provide helpful information when case reporting might be delayed or incomplete. All acute care hospitals in Illinois are required send syndromic surveillance data on emergency department and inpatient visits. These data are provisional and subject to change.

The graph below shows the percentage of all emergency department (ED) visits made by suburban Cook County residents for COVID-19-like illness (CLI). CLI is defined as fever plus cough or shortness of breath, or given a diagnosis of COVID-19. The percentage of ED visits for these symptoms at this time last year is included for comparison.





In addition to emergency visits, hospitals also submit syndromic data for inpatients. The graph below shows the number of inpatient admissions for CLI per day among suburban Cook County residents. This metric is being tracked on a regional level by the Illinois Department of Public Health as a part of the Restore Illinois Plan.





Syndromic surveillance data is also required to include the patient's race and ethnicity when available in the hospital's medical record. The graph below displays inpatient hospital admissions for CLI by race and ethnicity. In this graph, rates are displayed instead of counts to better visualize the true impact on these groups. Rates are calculated with populations from the 2010 United States Census.

