Dr. Rochelle Walensky, Director of the Centers for Disease Control and Prevention (CDC); Dr. Janet Woodcock, Acting Commissioner, Food and Drug Administration (FDA); Dr. Anthony Fauci, Chief Medical Advisor to President Joe Biden and others issued a prepared statement Aug. 18 concluding that a booster shot will be needed “to maximize protection” of the Pfizer and Moderna vaccines and likely the Johnson & Johnson vaccine.

While stating that these vaccines continue to be “remarkably effective in reducing risk of severe disease, hospitalization, and death, even against the widely circulating Delta variant,” they add, “The available data make very clear that protection against SARS-CoV-2 infection begins to decrease over time following the initial doses of vaccination, and in association with the dominance of the Delta variant.”

They said they are starting to see evidence of reduced protection against “mild and moderate disease” and that “the current protection against severe disease, hospitalization, and death could diminish in the months ahead, especially among those who are at higher risk or were vaccinated during the earlier phases of the vaccination rollout.”

The group has developed a plan to begin offering booster shots this fall “subject to the FDA conducting an independent evaluation and determination of the safety and effectiveness of a third dose of the Pfizer and Moderna mRNA vaccines and CDC’s Advisory Committee on Immunization Practices (ACIP) issuing booster dose recommendations based on a thorough review of the evidence.

“Our top priority remains staying ahead of the virus and protecting the American people from COVID-19 with safe, effective, and long-lasting vaccines especially in the context of a constantly changing virus and epidemiologic landscape. We will continue to follow the science on a daily basis, and we are prepared to modify this plan should new data emerge that requires it.”

The statement continued, “We also want to emphasize the ongoing urgency of vaccinating the unvaccinated in the U.S. and around the world. Nearly all the cases of severe disease, hospitalization, and death continue to occur among those not yet vaccinated at all.”

The group said they will continue to ramp up efforts to increase vaccinations in the U.S. and to expand efforts to increase the supply of vaccines for other countries.

Recent Trends

New Cases: The weekly number of new cases per 100,000 people in Illinois increased to 183 for the week ending today, Aug. 19, a 12% increase from the week ending Aug. 12. The number of new cases per week in the State are now 695% higher than they were on June 10, the day before the State moved to Phase 5 of the Restore Illinois Plan. The trend is up.

The above chart illustrates that the trends of new cases per week are also up in suburban Cook County and Chicago. The trend for Evanston is down this week. The number of new cases per 100,000 for Evanston, suburban Cook County, Chicago and Illinois is Evanston – 62; suburban Cook County – 123; Chicago – 122; and Illinois – 183.

Under CDC guidelines, Evanston is considered an area with “substantial transmission.” Suburban Cook County, Chicago and Illinois are considered to be areas of “high transmission.” See Footnote 1.

Test Positivity Rates: The seven-day test-positivity rates in each region are Evanston – 1.7%; suburban Cook County – 5.0%; Chicago – 4.2%; and Illinois – 6.2%. 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 6.2% today. See footnotes 2 and 3.

Vaccinations: The number of people in the State who are vaccinated continues to grow, but at a very slow pace. As of Aug. 19, 75.2% of Illinois residents who are 12 and older had at least one dose of a vaccine, up from 74.2% on Aug. 12; and 58.3% were fully vaccinated, compared to 57.5% on Aug. 12. 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 36,487, up from 27,611 one week ago. (Source: CDC and Illinois Department of Public Health.)

As of Aug. 19, 86.1% of Evanston residents 12 and older had received at least one dose of a vaccine and 79.4% were fully vaccinated. There was little change from the prior week. (Source: City of Evanston.)

Delta Variant: According to data published by the IDPH, in the last seven days there were 1,329 new cases of the Delta variant in Illinois, comprising about 6% of the total new cases in the State in that same period. On a nationwide basis, about 80% of the new COVID-19 cases are due to the Delta variant. Why the State percentage is so much lower than the national level is not clear.

Evanston – COVID

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

There has been a total of 46 new COVID-19 cases of Evanston residents in the last seven days, compared to 62 in the prior seven days.

The seven-day test positivity rate today is 1.7%.

There has been a total of 4,859 COVID-19 cases of Evanston residents during the pandemic, 47 of which are active.

No Evanstonian has died due to 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 Aug. 13 and Aug. 19, there were 27 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 has been covering COVID-19 metrics once a week on Thursdays.  Specifically, the RoundTable is presenting two 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 gauge 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 3 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/ In late July, the Centers for Disease Control and Prevention (CDC), the Illinois Department of Public Health (IDPH), and Evanston’s Health & Human Services Dept. each adopted recommendations 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. Areas of substantial transmission are considered to be those with between 50 and 99 cases per 100,000 people over a 7-day period. Areas of high transmission are considered to be those with more than 100 cases per 100,000 people over a 7-day period.

They also recommend universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. 

3/ 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

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...

One reply on “COVID-19 update on Aug. 19: Nine new cases in Evanston today, 3,180 in the State”

  1. The positivity rate given by the City is much lower than the real rate. The City has added the same number of tests given for each of the three weekend days, e.g 386 each day for Friday, Saturday and Sunday, rather than 386 total for the entire weekend, They’ve done that for each weekend on their chart. If you eliminate the two extra days each weekend, the real positivity rate is much higher, unfortunately,

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