The daily number of newly confirmed coronavirus cases reported by Illinois officials on Thursday topped 3,000 for the first time in almost five months, except for a day in early September when the state caught up on a testing backlog.
The announcement of 3,059 new cases came a day after Gov. J.B. Pritzker cautioned that progress against the disease in Illinois had leveled off a bit in recent days. But it is also part of a rollercoaster pattern of a virus that peaked in the spring, reached hopeful lows in early summer only to start rising again as business reopened and classes began for many students.
The Department of Public Health is more focused on longer-term data than any single-day figures, said agency spokeswoman Melaney Arnold, who noted the number of tests reported Thursday was significantly higher than the state’s testing capacity in May.
“While IDPH does report the daily number of new cases, it is more informative to look at trends over time and using seven-day rolling averages,” Arnold said in an email.
The daily number of newly confirmed cases last topped 3,000 on May 14, when officials reported 3,239 cases. The department reported 5,368 new cases on Sept. 4, but that was due to a backlog in processing test results.
In addition to Thursday’s newly confirmed cases, which bring the total number of known infections to 310,700 statewide since the pandemic began, officials on Thursday reported 32 more fatalities. That brings the death toll to 8,910.
The state received results from a near-record number of coronavirus tests in the previous 24 hours, with 72,491 screenings reported for a single-day positivity rate of 4.2%.
The highest number of tests reported in a single day was 74,286 on Sept. 19, but there were only 2,529 new cases reported that day, a positivity rate of 3.4%.
For comparison, the one-day positivity rate on May 14 was 14.2% because the 3,239 positive results came from just 22,678 tests.
To smooth out day-to-day fluctuations in the data, health officials look at the positivity rate on a seven-day rolling average. The average for the period ending Wednesday, the most recent available, was 3.7% statewide. The statewide rate has been trending upward over the past few days after dropping as low as 3.3% for the period ending Saturday.
Pritzker warned Wednesday that the state’s progress in combating the pandemic had “cooled off a bit, across Illinois.”
“We are seeing changes in positivity averages around the state level off, with three regions that were decreasing last week now sitting at a stable level,” Pritzker said.
Still, the statewide positivity rate sits slightly below where it was a month ago, when the seven-day average was 4%.
But the seven-day average for newly confirmed cases also is trending upward.
For the week ending Thursday, the average was 2,180 cases per day. Setting aside the backlog period in early September, the seven-day average of new cases hadn’t topped 2,100 since the week ending May 26.
The seven-day average peaked at 2,565 cases on May 4 and 7. The single-day high was 4,014 cases reported May 12.
While it’s too early to draw any hard conclusions from the data, public health officials have long warned that the U.S. could see cases of COVID-19 peak once again as we move into the colder months and people spend more time indoors, where the virus that causes the disease is more easily transmitted.
Some of Illinois’ neighbors have been struggling recently to keep the virus under control, most notably Wisconsin, where officials next week plan to open a field hospital at the state fairgrounds to help prevent hospitals from becoming overwhelmed.
Wisconsin’s population of 5.8 million is less than half of Illinois’, but the state also reported more than 3,000 new coronavirus cases Thursday, crossing that threshold for the first time.
The White House coronavirus task force warned Iowa in a report earlier this week that “community transmission has remained high across the state for the past month, with many preventable deaths.”
After Pritzker issued a stay-at-home order in March and a mask mandate in May, the seven-day average for new cases in Illinois fell below 1,000 on June 9 and remained there for more than a month. The statewide positivity rate dropped as low as 2%.
But many restrictions that had been in place, such as a prohibition on indoor dining at restaurants and bars, were lifted June 26 when the state moved into phase four of Pritzker’s reopening plan. By the end of July, the state was averaging nearly 1,500 cases per day, and the positivity rate had nearly doubled, to 3.9%.
By mid-August, Pritzker was using a revised mitigation strategy to clamp down on regions where the coronavirus appeared to be gaining new footholds. The Metro East region near St. Louis has been under stricter rules, including tighter restrictions on restaurants and bars, since Aug. 18. The governor has said those rules may be eased Friday.
The northwest region of the state, including DeKalb, Rockford and Galena, has been under tighter restrictions since last week. Will and Kankakee counties were subject the stricter rules for about three weeks, from late August until mid-September.
jmunks@chicagotribune.com
