Illinois case positivity rate drops to lowest point during pandemic

  • Illinois Department of Public Health records show that 75% of all residents 65 and older in Illinois are fully vaccinated, while 80% have had at least one dose of the COVID-19 vaccine.

    Illinois Department of Public Health records show that 75% of all residents 65 and older in Illinois are fully vaccinated, while 80% have had at least one dose of the COVID-19 vaccine. Mark Welsh | Staff Photographer, March 8

Updated 5/26/2021 6:27 AM

At just 2.11%, the statewide seven-day case positivity rate for COVID-19 is at the lowest point since the pandemic began.

At the peak in November, the state's seven-day case positivity rate had reached more than 13%. The statistic measures the percentage of new cases from a batch of COVID-19 tests and indicates the level of infection within the population.


"The COVID-19 totals in suburban Cook County, much like the state, are continuing a downward trend," said Dr. Rachel Rubin, senior medical officer and co-lead at the Cook County Department of Public Health. "These totals, combined with nearly 1.2 million suburban Cook County residents receiving at least one dose of the vaccine, provide hope that we are over the latest surge of cases and that we can look forward to entering Phase 5 reopening soon."

The state is set to reopen with no restrictions June 11.

Case positivity is one of several metrics public health officials use to determine whether any restrictions are needed to slow the spread of the virus. It's considered a leading indicator, looking forward to the road ahead in the battle against COVID-19.

In contrast, hospitalizations and deaths are lagging indicators, pointing to disease spread that might have occurred weeks or months earlier.

In mid-March, the case positivity rate dipped as low as 2.14%, according to Illinois Department of Public Health figures. At that time, the state was averaging 1,511 new cases a day over the course of the week and 70,568 daily test results during the same period.

On Tuesday, the state averaged 1,220 new cases daily over a week while also averaging 57,737 tests results each day that week. A seven-day average is used to smooth out any anomalies in the daily reporting of new cases and test results.

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"I can't emphasize enough how well this vaccine is working," Chicago Department of Public Health Commissioner Allison Arwady said Tuesday. "The way the case rates are looking are the inverse of how the vaccination rates are looking."

Arwady said areas seeing higher rates of new cases also have fewer vaccinated residents.

In Chicago, the seven-day case positivity rate is slightly above 2%, the lowest in more than a year, according to IDPH figures.

In the suburbs, Lake County is reporting the lowest seven-day case positivity rate at 1.3%. McHenry County's is highest at 3.2%.

The rate is 2.2% in Will County, 2.6% in DuPage County, 2.8% in suburban Cook County and 2.9% in Kane County.

State health officials report that more than 40% of people in the state are fully vaccinated. A person is considered to be fully vaccinated two weeks after the final dose of the vaccine.


The U.S. Centers for Disease Control and Prevention is reporting 49% of adults in Illinois are fully vaccinated, and 65% of adults have had at least one shot.

IDPH officials also report that 49,402 more doses of the COVID-19 vaccine had been administered throughout the state over the past 24 hours.

That brings the total number of vaccine doses administered in Illinois to 10,990,171.

Of the three vaccines available, the Pfizer and Moderna vaccines require two doses, but Johnson & Johnson requires just one shot. However, only Pfizer has been approved for use in 12- to 17-year-olds. The other two vaccines are allowed only for those 18 and older.

In their daily update, state health officials said 17 more people had died in Illinois and 808 new cases were reported.

It's the first time since mid-July 2020 the state has reported fewer than 1,000 new COVID-19 cases for three days in a row.

Since the outset of the pandemic, 22,650 Illinois residents have died from COVID-19 and 1,377,249 have been infected, according to state figures.

Illinois hospitals are treating 1,419 COVID-19 patients, 350 of whom are in intensive care beds, IDPH records show.

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