The Illinois Department of Public Health announced on Tuesday that it fully adopted the updated masking recommendations of the Centers for Disease Control and Prevention to protect against COVID-19 and the Delta variant. CDC and IDPH recommend that everyone, including fully vaccinated people, wear a mask in a public indoor setting in areas with “substantial” and “high transmission” of new COVID-19 cases. They also recommend universal indoor masking for all teachers, staff, students and visitors to K-12 schools, regardless of vaccination status. 

“While data continues to show the effectiveness of the three COVID-19 vaccines currently authorized in the U.S., including against the Delta variant, we are still seeing the virus rapidly spread among the unvaccinated,” said IDPH Director Dr. Ngozi Ezike. “Cases and hospitalizations due to COVID-19 both continue to increase, overwhelmingly among the unvaccinated, but the risk is greater for everyone if we do not stop the ongoing spread of the virus and the Delta variant. We know masking can help prevent transmission of COVID-19 and its variants. Until more people are vaccinated, we join CDC in recommending everyone, regardless of vaccination status, wear a mask indoors in areas of substantial and high transmissions, and in K-12 schools.”

IDPH said in a prepared statement, “According to CDC, data show the Delta variant is much more contagious. Delta spreads more than twice as easily from one person to another compared to other strains. According to CDC, the Delta variant is causing some vaccine breakthrough infections, but even so, most breakthrough infections are mild, and the vaccines are preventing severe illness, hospitalization, and death.”

Areas of substantial transmission are considered to be those with 50 to 99 cases per 100,000 people over a seven-day period. Areas of high transmission are considered to be those with more than 100 cases per 100,000 people over a seven-day period.

Evanston’s Health & Human Services Dept. has adopted the CDC and IDPH recommendations. The City said in a prepared statement this evening, though, “At this time, Evanston is not considered to be an area of substantial or high transmission; however, Evanston businesses and venues may continue to require face coverings regardless of vaccination status.”

Recent Trends

New Cases: The weekly number of new cases per 100,000 people in Illinois is 85 for the week ending July 29, a 70% increase from the week ending July 22. The number of new cases per week in the State are now 270% higher than they were on June 10, the day before the State moved to Phase 5. The trend is up.

In the last several weeks, the trends of new cases per week are also up in Evanston, suburban Cook County and Chicago. The number of new cases per 100,000 in each region in the past week are:

Evanston – 41

Suburban Cook County – 51

Chicago – 56

As previously noted, an area with between 50 and 99 new cases per 100,000 people in the latest week are considered to be an area with “substantial transmission.”

Test Positivity Rates: The seven-day test-positivity rates in each region are: Evanston – 1.7%; suburban Cook County – 2.9%; Chicago – 2.8%; and Illinois – 4.6%. The relatively low rates suggest that the amount of testing in each region is adequate. But the test positivity rates are trending up in each region. For example, the State’s rate has moved up from 1.6% on July 8 to 4.6% today. See Footnotes 1 and 2.

Vaccinations: The number of people in the State who are vaccinated continues to grow, but at a very slow pace. As of July 29, 72.1% of Illinois residents 12 and older had at least one dose of a vaccine, up from 71.3% on July 22; 56.3% were fully vaccinated on July 29, up from 55.8% on July 22 These percentages include people who reside in Illinois and have been vaccinated in Illinois or in other states. The seven-day average for vaccinations is down to 21,291. (Source: CDC and IDPH.)

As of July 26, 85% of Evanston residents 12 and older had received at least one dose of a vaccine; 78% were fully vaccinated. (Source: City of Evanston.)

Delta Variant: According to data published by IDPH, in the last seven days, there were 215 new cases of the Delta variant in Illinois, comprising about 2.7% of the total new cases in the State in that same period.

On the national level, public health experts continue to express concern about the spread of the Delta variant and the relatively high percentage of people who have not been vaccinated. Some estimates say the Delta variant accounts for more than 75% of all new infections in the United States. The vast majority of people with new COVID-19 cases are those who have not been vaccinated.

Evanston – COVID

Evanston reported six new COVID-19 cases of Evanston residents today, compared to three yesterday, and five on Tuesday.    

There have been a total of 30 new COVID-19 cases of Evanston residents in the last seven days, and a total of 1,781 tests administered to Evanston residents in that same period. The seven-day test positivity rate is 1.7%.

There has been a total of 4,698 COVID-19 cases of Evanston residents during the pandemic, 24 of which are active.

No Evanstonian has died from COVID-19 since May 31. The number of deaths due to COVID-19 is 118.

Impact of Northwestern University. The most recent data on Northwestern University’s website reports that between July 16 and July 22, there were eight new confirmed COVID-19 cases of an NU faculty member, staff member or student. If the faculty member, staff member or student resides in Evanston, the case or cases would be included in the City’s numbers.  


1/ The State moved to Phase 5 of the Restore Illinois Plan on June 11. As of July 1, the RoundTable plans to cover COVID-19 metrics once a week on Thursdays.  Specifically, we plan to provide charts showing: 1) the trends in the number of new COVID-19 cases per 100,000 people in two recent seven-day periods for Evanston, Chicago, Suburban Cook County, and the State. The chart also shows the weekly numbers of new cases for each region as of June 10 as a baseline to guage whether cases are going up since the move to Phase 5; and, 2) the most recent test positivity rates for these areas.  

As discussed in footnote 2 below, the CDC recommends that these two measures be used to determine the level of risk of transmission.  If we see a surge in new cases or in the test positivity rates, we will consider covering additional metrics.

We will also report the most recent percentages of vaccinated people, 12 years and older, in Evanston and Illinois.

2/ On Feb. 12, the CDC issued a K-12 School Operational Strategy. As part of that strategy, the report says CDC recommends the use of two measures to determine the level of risk of transmission: 1) the total number of new cases per 100,000 persons in the past 7 days; and 2) the percentage of COVID tests during the last seven days that were positive. The CDC provides a chart to assess whether the risk of transmission is low, moderate, substantial, or high. If the two indicators suggest different levels of risk, CDC says the higher level of risk should be used. The table below, reprinted from CDC’s report, provides CDC’s Indicators and Thresholds for Community Transmission of COVID-219.

CDC’s guidelines are available here: Operational Strategy for K-12 Schools through Phased Prevention | CDC

City’s vaccine information.

Larry Gavin

Larry Gavin was a co-founder of the Evanston RoundTable in 1998 and assisted in its conversion to a non-profit in 2021. He has received many journalism awards for his articles on education, housing and...