Rate of positive coronavirus tests in Illinois drops below 10%, Gov. J.B. Pritzker says
The number of coronavirus tests that come back positive is decreasing statewide, Gov. J.B. Pritzker said Friday.
The positivity rate can show how widespread COVID-19 infections are among the population, the governor said. A declining rate is one of the guidelines to determine when a region moves to the next phase in Pritzker’s reopening plan.
In the 24 hours prior to the governor’s daily news conference, 9.2% of the more than 26,000 tests performed statewide came back positive, Pritzker said.
That’s down from the state’s peak positivity rate on April 4, when 23.6% of tests came back positive on a rolling average — or an average over time. Over the past seven-day rolling average, 12% of the tests came back positive.
But Pritzker warned against “reading too far into this decline” because the lower rate can be caused by increased testing, a statistical concept called inverse correlation.
The state drastically increased the number of tests performed each day, with an average of 20,000 tests in the past week.
Recent positivity rates are more reliable than when testing was more limited, Pritzker said. Eligibility for testing has expanded to include not just those who show coronavirus-like symptom or who came into contact with a COVID-19 patient, but to front-line workers, essential workers, nursing home staff and others more at risk of catching the disease.
“Testing is fundamental to our ability to reopen the economy,” Pritzker said. “There is more to come and much more for us to do.”
One of the health department’s next steps is to announce guidelines on antibody tests, which could determine if a COVID-19 patient has developed immunity to the disease. The tests could inform best practices in reopening from the pandemic.
Accuracy of tests currently on the market varies, said Illinois Department of Public Health Director Dr. Ngozi Ezike, but Illinois researchers are gathering information that will be used in the state’s guidance.
“Even if we do know that people develop antibodies, it’s not clear how long that protection would last, the level of antibodies that would be protective,” Ezike said. “I think there are more questions than answers at this point.”
Public health officials Friday announced 2,432 new cases of coronavirus statewide including 130 additional deaths for a total of 90,369 cases, including 4,058 deaths.
This story was originally published May 15, 2020 at 3:47 PM.
