Community Transmission and Risk

Centers for Disease Control and Prevention (CDC) COVID-19 Community Levels

CDC Community COVID-19 Risk Level - Medium

COVID-19 Community Levels have been developed by the CDC to help communities decide what prevention steps to take based on the latest local COVID-19 data. Levels are determined each week for each county in the U.S. A county’s risk level can be low, medium, or high based on a combination of three metrics: the number of new local COVID-19 cases; the number of new local COVID-19 hospital admissions; and the proportion of local hospital beds occupied by patients with COVID. 

The Chicago Department of Public Health tracks and reports these metrics daily for City of Chicago residents. The Cook County Department of Public Health tracks and reports these metrics daily for suburban Cook County residents (excluding Chicago). When the CDC updates its COVID-19 Community Levels national map each week (typically on Thursday evenings), both City of Chicago and suburban Cook County daily data are combined into one weekly case metric for Cook County. Hospitalization data, in contrast, reflect burden on the whole federally defined Health Service Area, which includes hospitals in Cook, Lake, DuPage, and McHenry counties. 

CDPH continues to track and report COVID-19 hospital burden specifically for Chicago hospitals every day on its dashboard. Locally, Chicago will adjust its community level if EITHER the City or Cook County reach a Community Level threshold as determined by CDC. However, major mitigation changes (e.g. citywide indoor mask mandates) will be made based specifically on City of Chicago's COVID-19 hospital burden rather than the federally defined Health Service Area. CDPH will update this level on Fridays.

To see the CDC’s U.S. map and read more about county COVID-19 Community Levels, visit here.


About the Data

Numbers displayed on this site are derived from publicly-available sources. The City of Chicago shares data through the Chicago Data Portal. COVID-19 cases and hospital admissions for the City of Chicago are obtained from the COVID-19 Daily Cases, Deaths, and Hospitalizations dataset, and the proportion of staffed inpatient beds in the City of Chicago occupied by COVID-19 patients is estimated using the COVID-19 Hospital Capacity Metrics dataset. Community level metrics for Cook County (including City of Chicago) are calculated and published to data.cdc.gov by the Centers for Disease Control and Prevention (CDC). See https://data.cdc.gov/Public-Health-Surveillance/United-States-COVID-19-Community-Levels-by-County/3nnm-4jni for more information. Population estimates are from the U.S. Census Bureau 2019 American Community Survey 1-year estimate.

City of Chicago Metrics:

Case rate and new hospital admission rate for the City of Chicago are calculated as the total number of cases and new admissions in the past 7 days, respectively, divided by the total population of Chicago and multiplied by 100,000. The percentage of all staffed inpatient beds in the City of Chicago occupied by patients with laboratory-confirmed COVID-19 (including both adult and pediatric patients) is calculated by dividing the average count of hospital beds occupied by COVID-19 patients over the last 7 days by the average total bed capacity over the last 7 days. Both ICU and non-ICU hospital beds are included in these estimates.

Cook County (including City of Chicago) Metrics:

The case rate for Cook County is calculated as the total number of new cases among Cook County residents (including Chicagoans) in the past 7 days divided by the total population of Cook County and multiplied by 100,000. The hospital admission rate and the percent of staffed inpatient beds occupied by COVID-19 patients is based on Health Service Areas; the Health Service Area for Cook County also includes Lake, DuPage, and McHenry counties. The new hospital admission rate for Cook County is calculated as the total number of new COVID-19 patients admitted to hospitals located in the Health Service Area in the past 7 days divided by the population of Cook, Lake, DuPage, and McHenry counties and multiplied by 100,000. The percentage of all staffed inpatient beds occupied by patients with laboratory-confirmed COVID-19 (including both adult and pediatric patients) is calculated by dividing the average count of hospital beds in the Health Service Area occupied by COVID-19 patients over the last 7 days by the average total bed capacity over the last 7 days.

All data are provisional and subject to change. Numbers in this dataset may differ from other public sources due to when data are reported and how City of Chicago boundaries are defined.


MEDIUM

In “Medium” risk, the Chicago Department of Public Health recommends individuals: 

  • Stay up to date* with COVID-19 vaccines
  • Wear a face mask in indoor public settings where vaccine status is not known
  • Get tested if you have symptoms
  • Follow all isolation and quarantine guidance, including wearing a face mask
  • If you are at high risk for severe illness, talk to your healthcare provider about whether you need to wear a mask and take other precautions

NEW COVID-19 Cases 

(Per 100,000 people in the past 7 days)

Indicators Low Medium High
Fewer than 200 New COVID-19 admissions per 100,000 population (7-day total) <10.0 10.0-19.9 ≥20.0
Percent of staffed inpatient beds occupied by COVID-19 patients (7-day average) <10.0% 10.0-14.9% ≥15.0%
200 or more New COVID-19 admissions per 100,000 population (7-day total) NA <10.0 ≥10.0
Percent of staffed inpatient beds occupied by COVID-19 patients (7-day average) NA <10.0% ≥10.0%

The COVID-19 community level is determined by the higher of the inpatient beds and new admissions indicators, based on the current level of new cases per 100,000 population in the past 7 days.

For those traveling, the Chicago Department of Public Health (CDPH) recommends Chicagoans take precautions against COVID-19 if visiting areas of the United States that have clusters of medium to high COVID-19 risk levels, based on the CDC’s COVID-19 Community Levels.  View the City’s Travel Advisory (updated weekly) to learn more.  

Low

There is low community spread and limited impact on healthcare system. 

Medium

There is medium community spread and/or some impact on the healthcare system. 

  • Stay up to date* with COVID-19 vaccines
  • Recommend wearing a face mask in indoor public settings where vaccine status is not known
  • Get tested if you have symptoms
  • If you test positive for COVID-19, follow all isolation guidance, including wearing a face mask
  • If you are at high risk for severe illness, talk to your healthcare provider about whether you need to wear a mask and take other precautions 

High

There is high community spread and high potential for healthcare system strain.  

  • Wear a mask indoors in public
  • Consider avoiding higher-risk activities (such as crowded indoor gatherings) 
  • Limit gatherings to small numbers  
  • Stay up to date* with COVID-19 vaccines
  • Get tested if you have symptoms
  • If you test positive for COVID-19, follow all isolation guidance, including wearing a face mask
  • Additional precautions may be needed for people at high risk for severe disease

*Up-to-date means a person has received all recommended COVID-19 vaccines, including any booster dose(s) when eligible.

Masks are effective at reducing transmission of COVID-19. Regardless of county risk level, people may choose to wear a mask at any time, even if they are vaccinated. People with symptoms, a positive COVID-19 test, or exposure to someone with COVID-19 should wear a mask. 


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