Illinois' coronavirus numbers have looked much higher over the last week, which health officials said is because of how the state now reports new cases and deaths.
Illinois Department of Public Health said as of last Friday, officials will "report confirmed cases and probable cases combined" under guidance from the Centers for Disease Control and Prevention.
"A confirmed case is laboratory confirmed via molecular test. A probable case meets clinical criteria AND is epidemiologically linked, or has a positive antigen test," IDPH said in announcing the new cases and change in reporting. "If a probable case is later confirmed, the case will be deduplicated and will only be counted once. Probable deaths and confirmed deaths will continue to be reported separately."
Illinois began distributing rapid antigen tests from the federal government last month, and the state's top doctor expects as more of those tests are conducted "we will get more probable cases."
"Now that we have gotten hundreds of thousands of tests from the federal government, and we've been passing those out to local health departments in different places where we're piloting its use, those are not considered when you get the positive test in that those are not considered confirmed cases, those are called probable cases," Illinois Department of Public Health Director Dr. Ngozi Ezike said. "But we are treating - I mean, that is a positive. You have COVID if you come up with a positive test on that BinaxNOW test. So that is part of our caseload in terms of people who now have been diagnosed with COVID, and that we need to identify their contacts and that they need to isolate, etc. So total will now be the combination of confirmed cases, plus probable cases."
"The antigen test, particularly the ones that the federal government has distributed to us and to many other states, are a little less sensitive than the PCR tests," Illinois Gov. J.B. Pritzker said last week. "So that's why they're, you know, slightly, I don't want to say they're less accurate - I mean, they have a different sensitivity level. And the result is that that's why they've been labeled slightly differently. But if you get an antigen test done, and it tests you positive, it is very, very likely that you are a positive."
In addition, the state has added all probable cases from the pandemic so far to its total number of cases, meaning the statewide total increased by 7,600 in one day.
"If we go back, trying to remember the time where we didn't have 100,000 tests a day, there was a time when we said, if you have the symptoms, you're around somebody who has COVID, you have the fever, you have this, you have that - you have COVID. You don't need to get a test, partly because we didn't have access for everyone," Ezike said. "So those individuals that were made known to the local health department also got listed as probable cases because they were linked to someone who was known to have it, but didn't have a confirmatory test. So those probable cases had been counted, but we've never included them. Now, we're bringing all of that data back for probable cases - the antigen forms, probable cases - and putting it with our confirmed cases from the molecular test."
With the change, Illinois reported more than 10,000 new confirmed and probable coronavirus cases for the third consecutive day in a row on Sunday, along with 42 additional fatalities.
In all, 10,009 new cases were reported over the last 24 hours in the state, bringing the total to 487,987 during the pandemic.
The state also reported 42 additional deaths related to the virus on Sunday, bringing the state’s total number of fatalities to 10,196. Another 342 deaths are classified as “probable” COVID-19 related deaths.
Testing continues to expand in the state, with 90,757 new tests performed over the last 24 hours, according to IDPH data. In all, 8,404,304 tests have been performed during the pandemic.
The state’s seven-day positivity rate has continued to climb in recent days, with 11.9% of total tests coming back positive over the last week, according to IDPH figures.
The state also saw its hospitalization numbers continue to increase on Sunday, as more than 4,300 residents are currently in hospitals due to coronavirus-like illnesses. Of those patients, 833 are currently in intensive care units, and 368 are on ventilators.
All three statistics are the highest metrics the state has seen in their respective categories since the first peak in COVID-19 cases earlier this year.