As case positivity rates drop to July levels, 31 more school outbreaks reported in suburbs

  • Illinois Department of Public Health records show 2,082 COVID-19 patients are being treated at hospitals statewide, 502 of whom are in intensive care.

    Illinois Department of Public Health records show 2,082 COVID-19 patients are being treated at hospitals statewide, 502 of whom are in intensive care. Associated Press file photo/October 2020

Updated 9/17/2021 5:29 PM

COVID-19 case positivity rates in the suburbs and Chicago have dropped below 4% for the first time since July 24.

The rate in some suburban counties had surpassed 6% last month, according to Illinois Department of Public Health records.


But this week also saw 31 more COVID-19 outbreaks at suburban schools, IDPH reported.

Case positivity measures the rate of new cases out of tests administered, and it often is given as a seven-day average to account for any daily anomalies and better show trends.

Chicago's seven-day case positivity rate is the lowest in the region at 2.8%, and the highest is in Will County at a little more than 3.9%.

Suburban Cook County is reporting a seven-day case positivity rate of just under 3%, while Lake County's is at 3.5%, Kane County's is at 3.7% and DuPage County's is at 3.8%.

In McHenry County -- where the seven-day case positivity rate had climbed to nearly 7.8% in August -- the rate is just below 3.9%, according to IDPH data.

The statewide seven-day case positivity rate is 4.06%, the first time it's been that low since July 30.

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While the daily number of new cases in each county and Chicago has remained relatively flat for the past few weeks, the amount of testing has increased substantially, mostly at schools.

There are now 83 school-related outbreaks in the suburbs over the past 30 days, IDPH records show. School outbreak information, which is updated on Fridays, can be found at the agency's data tracking website,

Outbreaks are defined as two or more COVID-19 cases linked through a common exposure, which in the case of schools can be in classrooms or sporting events.

In suburban Cook County there are now 26 outbreaks in schools over the past 30 days, up from 14 last week. DuPage County now has 16 school outbreaks.

There have been 13 outbreaks reported at Kane County schools over the last 30 days, and 12 in McHenry County.


There are also 16 outbreaks reported at Will County schools, but none in Lake County.

IDPH officials also said Friday that 2,082 patients were being treated for COVID-19 infections in hospitals throughout Illinois. That's down 81 patients from the day before.

Of those currently hospitalized, 502 are in intensive care.

Many hospitals are reporting the majority of current COVID-19 patients are unvaccinated.

IDPH officials also reported Friday that 54 more people died from the virus and 3,601 new cases were diagnosed.

That brings the state's death toll from COVID-19 to 24,546, with 1,590,342 cases of the respiratory disease diagnosed since the outset of the pandemic.

IDPH officials also reported another 21,372 doses of COVID-19 vaccine have been administered statewide.

Vaccine providers in Illinois have now administered 14,284,288 vaccine inoculations since they were made available nine months ago.

IDPH records show 54.3% of the state's population is fully vaccinated.

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