On Jan. 10, the Discovery Partners Institute (DPI), a part of the University of Illinois system, and the Illinois Department of Public Health (IDPH) announced there is a new website that tracks the levels of Covid in wastewater samples in Chicago and other cities across Illinois.
“This data is now going to be available to researchers and the public alike, giving everyone as accurate picture as possible for the pandemic,” said Bill Jackson, executive director of DPI. “This is a game-changer in terms of transparency and public health awareness, and we applaud IDPH for partnering with us on this bold step.”
“Wastewater surveillance is a great tool that can help detect and monitor COVID-19, the flu and other pathogens,” said Dr. Sameer Vohra, IDPH director. “This new website is designed to inform and educate residents of Illinois and will give them the ability to make informed decisions about how to protect themselves.”
On the new site, visitors can search for up-to-date figures and trendlines from any one of 75 wastewater treatment plants around Illinois that are voluntarily collecting samples of raw sewage to be screened for the SARS-CoV-2 virus, said IDPH in a prepared statement.
Samples are collected twice a week and taken to a high-throughput lab at the University of Illinois Chicago for analysis and then to Argonne National Laboratory for genetic sequencing to identify virus variants.
“Monitoring wastewater for the coronavirus has been proven to be an accurate and cost- effective way to measure covid’s presence in a community,” continued Dr. Vohra. “Genetic material from viruses and other germs is excreted in the feces and urine of infected people, eventually showing up in the raw sewage piped into purification facilities.
Public health authorities increasingly have come to rely on wastewater tallies now that people generally have switched to doing at-home COVID-19 testing and are not reporting results.
New Covid cases in Evanston and Illinois
In Illinois, the seven-day average of new cases was 16,281 on Jan. 1, the most recent data for which data was presented on IDPH’s website. This is down from 18,069 in the prior week. IDPH no longer reports the number of new Covid cases on a daily basis, but has shifted to providing weekly data.
In Evanston, the seven-day average of new cases was 15.0 on Jan. 11, down from 16.6 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 cases being publicly reported is generally regarded as grossly understated. 
Community risk rating
The Center for Disease Control and Prevention and IDPH look at a combination of three metrics to determine whether a community level of risk for covid is low, medium, or high. The graphic below shows how these metrics are combined. 
To be rated in the low category, an area must:
- 1) have less than 200 new covid cases per 100,000 population in the last seven days;
- 2) have less than 10 new hospitalizations per 100,000 population due to covid in the last seven days; and
- 3) have less than 10% of staffed inpatient beds occupied by covid patients (using the last seven-day average).
On Jan. 12, the City of Evanston reported that Evanston moved into the low category. The data reported by the City is as follows:
- New cases per 100,000 population: 134
- New hospital admissions due to Covid per 100,000 population: 7.68
- % staffed inpatient beds in use by patients with Covid: 3.96%.
The City also provided the following information about the trend of hospitalizations at Evanston and St. Francis hospitals.
CDC reported this evening that Cook County stayed in the medium risk category. The data for Cook County is as follows:
- New cases per 100,000 population: Not Available,
- New hospital admissions due to covid per 100,000 population: 13.8,
- % staffed inpatient beds in use by patients with covid: 6.1%.
CDC recommended steps
The CDC recommends that people should take certain steps to minimize the risk of contracting covid 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 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.
- Follow recommendations for isolation if you have suspected or confirmed covid.
- Follow the recommendations for what to do if you are exposed to someone with covid.
- If you are at high risk of getting very sick, talk with a healthcare provider about additional prevention action,
When the Covid 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 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 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 neither the State nor the City 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 outside the home, which would be reported to government officials. The number of new Covid cases reported by IDPH and the City thus significantly understates the actual number of new cases. Some studies have said the underestimated could be as much as 750% or more.
2/ CDC and IDPH use three indicators to measure Covid community levels:
- 1) New Covid cases per 100,000 population in the last seven days;
- 2) New Covid hospital admissions per 100,000 population in the last seven days; and
- 3) The percent of staffed inpatient beds occupied by patients with confirmed Covid (seven-day average).
The chart below illustrates how these indicators are combined to determine whether Covid community levels are low, medium or high. The CDC provides many recommendations depending on whether the community level is low, medium, or high. If the risk indicators relating to hospitalizations differ, the higher risk factor is used.