In Illinois, the seven-day average of new COVID-19 cases was 11,248 on Feb. 19, the most recent day for which data is available on Illinois Department of Public Health’s website.
This is up from 10,813 in the prior week, or an increase of 4%. The number of new cases per 100,000 population in Illinois is 88. IDPH no longer reports the number of new COVID-19 cases on a daily basis, but has shifted to providing a seven-day average once a week.
In Evanston, the seven-day average of new cases was 9.4 on Feb. 22, up slightly from 9.3 in the prior week. The chart below, prepared by the City of Evanston, reflects the number of new cases of Evanstonians for the last 30 days and the seven-day moving average.
The number of new COVID-19 cases being publicly reported is generally regarded as grossly understated. 
Community risk rating
The Centers for Disease Control and Prevention and IDPH look at a combination of three metrics to determine whether a community level of risk for COVID-19 is low, medium, or high. The graphic in footnote 2 below shows how these metrics are combined. 
To be rated in the low category, an area must: 1) have less than 200 new COVID-19 cases per 100,000 population in the last seven days; 2) have less than 10 new hospitalizations per 100,000 population due to COVID-19 in the last seven days; and 3) have less than 10% of staffed inpatient beds occupied by COVID-19 patients (using the last seven-day average).
On Feb. 23, the City of Evanston reported that Evanston remained in the low community risk category. The data reported by the city is as follows:
- New COVID-19 cases per 100,000 population: 85
- New hospital admissions due to COVID-19 per 100,000 population: 3.84
- % staffed inpatient beds in use by patients with COVID-19: 2.6%
The city also provided the following information about the trend of hospitalizations at Evanston and St. Francis hospitals.
CDC reported this evening, Feb. 9, that Cook County stayed in the low risk category. The data for Cook County is as follows:
- New COVID-19 cases per 100,000 population: 87.4,
- New hospital admissions due to COVID-19 per 100,000 population: 7.2,
- % staffed inpatient beds in use by patients with COVID-19: 3.1%.
CDC recommended steps
The CDC recommends that people should take certain steps to minimize the risk of contracting COVID-19 and to reduce the spread of the virus. There are six steps that apply to all community risk levels, another two for people in medium and high community risk areas, and two more for people in high community risk areas. The steps are:
At all COVID-19 Community Levels:
- Stay up to date on vaccination, including recommended booster doses.
- Maintain ventilation improvements.
- Avoid contact with people who have suspected or confirmed COVID-19.
- Follow recommendations for isolation if you have suspected or confirmed COVID-19.
- Follow the recommendations for what to do if you are exposed to someone with COVID-19.
- If you are at high risk of getting very sick, talk with a healthcare provider about additional prevention action,
When the COVID-19 Community Level is Medium or High:
- If you are at high risk of getting very sick, wear a well-fitting mask or respirator when indoors in public.
- If you have household or social contact with someone at high risk for getting very sick, consider testing to detect infection before contact and consider wearing a mask when indoors with them.
When the COVID-19 Community Level is High:
- Wear a well-fitting mask or respirator.
- If you are at high risk of getting very sick, consider avoiding non-essential indoor activities in public where you could be exposed.
1/The number of new COVID-19 cases being publicly reported by the City of Evanston and the State are significantly lower than the actual number of new cases being contracted. The City of Evanston says that the State and the City do not have a mechanism to report, verify or track at home test results. Because a positive at home test is regarded as highly accurate, most people who test positive in an at home test do not get a second test outside the home that is reported to government officials. The number of new COVID-19 cases reported by IDPH and the City thus significantly understates the actual number of new cases that are contracted. Some studies estimate the cases are underestimated by about 750% or more.
2/ CDC and IDPH use three indicators to measure COVID-19 community levels: 1) new COVID-19 cases per 100,000 population in the last 7 days; 2) new COVID-19 hospital admissions per 100,000 population in the last 7 days; and 3) the percent of staffed inpatient beds occupied by patients with confirmed Covid (7-day average).
The chart below illustrates how these indicators are combined to determine whether COVID-19 community levels are low, medium, or high. The CDC provides many recommendations depending on whether the COVID-19 community level is low, medium, or high. If the risk indicators relating to hospitalizations differ, the higher risk factor is used.
As I previously commented, the number of cases released each week by IDPH is the total number of Illinois cases for the state for the prior week, not a “seven day average” as your story reads; rolling seven day averages of DAILY cases are sometimes released (see the New York Times graphic. It is misleading to call the IDPH number a seven day average, as it implies that there are an average of that many cases per day, which would result in a much higher weekly figure for IL than the total case number IDPH is releasing each week.
Nonetheless thanks for the reports on the City, County and State