Illinois Regional COVID-19 Resurgence Criteria

IDPH is monitoring key indicators to identify early but significant  increases of  COVID-19 transmission in Illinois, potentially signifying resurgence. These indicators are calculated for eleven newly described  Illinois regions. IDPH will monitor if these indicators show an increase in COVID-19 disease burden  with a  simultaneous decrease in hospital capacity OR if there are three consecutive days greater than or equal to 8% test positivity rate (7 day rolling). These indicators can be used to determine whether additional community mitigation interventions are needed for a region to control the further spread of COVID-19.

Indicators are calculated daily for each region based on the most current, complete data. Each indicator is compared to a pre-established threshold value to evaluate the COVID-19 disease burden and hospital resource capacity. By applying the same metrics to each region, IDPH uses a standardized approach to monitor the state as a whole while also monitoring regional trends.

Once a region meets resurgence criteria, mitigation measures will be implemented.  If sustained increases in health metrics continue unabated, more stringent mitigation measures will be implemented. Tiered mitigation measures can be found here.

Region 4 Mitigation Measures

Data are provisional and are updated daily. Data updated:  

Region#

 

Test Positivity 7 Day Rolling Average

# Days of Positivity Increases

* Current Positivity #%

 

Hospital Admissions 7 Day Rolling Average

# Days of Hospital Admission Increases

 

Hospital Availability 3 Day Rolling Average

Med Surg Bed Availability

(20% threshold)

 

 

ICU Bed Availability

(20% threshold)

 

 

* Positivity Rate is based on data with a 3 day lag.

IL COVID-19 Regions Methodology

All indicators will be updated daily. Bed availability is calculated from the last three days of data received by IDPH, while the percentage test positivity and hospital admissions for COVID-like illness (CLI) are based on the last complete 10 days of data.  It takes three days to obtain this information.  In each case, the data are obtained one day before the numbers are posted publicly.  For example, data posted publicly on July 15 would have been received by IDPH on July 2-July 14.

Daily admission numbers for CLI reported on the IDPH regional COVID-19 Metrics website remain stable once publicly reported. The 7-day rolling average of admissions for CLI is calculated using the daily admission totals for the past 7 days that are available at the time the daily metrics are published.  If a region reaches 7 days of increasing CLI admissions in a 10 day period, along with a second metric, further investigation into the region’s data will be performed. This includes, but is not limited to, evaluating the 7-day rolling average for CLI admissions using any additional information received after publication for the most up-to-date daily CLI admission trends.

Test Positivity

The testing data represents data reported to IDPH through Electronic Laboratory Reporting (ELR) only.  It is based on the date results are reported into the ELR. It excludes testing data that are received from sites that have not implemented ELR. This excludes 3-5% of test data.

Each day, for each region, an average number (over the last 7 days) of COVID-19 positive tests is calculated and rounded to one decimal place.

Seven-day test positivity = 100 x [Region positive tests for 7 days] / [Region total tests for same 7 days]

  • Target: 7-day average test positivity less than 8%.
  • Warning: 7-day average test positivity at or above 8% for three consecutive days.

Increasing Test Positivity

The testing data represents data reported to IDPH through Electronic Laboratory Reporting (ELR) only.  It is based on the date results are reported into the ELR. It excludes testing data that are received from sites that have not implemented ELR. This excludes 3-5% of test data.

Each day, for each region, an average number (over the last 7 days) of COVID-19 positive tests is calculated and rounded to one decimal place.

Average test positivity = 100 x [Region positive tests for 7 days] / [Region total tests for same 7 days]

Whenever this average increases from the previous day, it is flagged.

Increase in test positivity = Number of days of the last 10 with a daily increase in the 7-day average test positivity.

  • Target: Fewer than 7 days in the last 10 with a daily increase in the 7-day average test positivity.
  • Warning: Seven or more days in the last 10 with a daily increase in the 7-day average test positivity.

Increasing Hospital Admissions for COVID-Like Illness

The number of COVID-like Illness (CLI) hospital admissions is measured using the Illinois Syndromic Surveillance System.  Each day, for each region, an average number (over the last 7 days) of CLI hospital admissions is calculated and rounded to a whole number.

Average CLI hospital admissions = [Region CLI hospital admissions for 7 days] / 7

Whenever this average increases from the previous day, it is flagged.

Increase CLI hospital admissions = Number of days of the last 10 with a daily increase in the 7-day average CLI hospital admissions.

  • Target: Fewer than 7 days in the last 10 with a daily increase in the average number of CLI hospital admissions
  • Warning: Seven or more days in the last 10 with a daily increase in the average number of CLI hospital admissions

Medical/Surgical Beds Percent Availability

Medical and surgical bed availability is reported daily by each hospital and represents the number of medical and surgical hospital beds that are empty. Hospitals are assigned to one of 11 Illinois COVID regions.  For each region, the sum of the available medical and surgical beds over the last three days is divided by the sum of the total medical and surgical beds (i.e., bed capacity) over the same period.

Weekly Medical/Surgical bed availability = 100 x [Sum of medical and surgical beds available in the region for 3 days] / [Total medical and surgical beds in the region for same 3 days]

  • Target: At least 20% of medical and surgical beds are available
  • Warning: Less than 20% of medical and surgical beds are available

ICU Percent Availability

Intensive Care Unit (ICU) availability is reported daily by each hospital and represents the number of ICU hospital beds that are empty. Hospitals are assigned to one of 11 Illinois COVID regions.  For each region, the sum of the available ICU beds over the last three days is divided by the sum of the total ICU beds (i.e., bed capacity) over the same period.

ICU availability = 100 x [Sum of ICU beds available in the region for 3 days] / [Total ICU beds in the region for same 3 days]

  • Target: At least 20% of ICU beds are available
  • Warning: Less than 20% of ICU beds are available