Gov. J.B. Pritzker clarified the difference in meanings between a COVID-19 outbreak and exposure Friday, as the two words have "very specific, distinct meanings in public health."
Pritzker defined an outbreak of the coronavirus as five or more cases that are linked to a particular setting during a 14-day period.
"The location of an outbreak is more difficult to identify than the location of an exposure," he added.
Linked cases must be from different households, according to Pritzker, and not also connected to other sources of the virus.
With frequently visited places, such as restaurants and grocery stores, outbreaks are not as easy to determine as an exposure to the coronavirus, Pritzker said.
He explained that factors such as the disease being respiratory and later onset of symptoms add to the difficulty of declaring official outbreaks of COVID-19.
"Much more useful is exposure data – particularly for the average person who wants to design their day to day in a way that reduces the most risk," Pritzker said. "Exposure data comes from contact tracers talking to confirmed positive COVID patients about the places they went in the time before they were symptomatic or tested positive."
Pritzker explained that exposure data is more useful because it gives a sense of where people are at greatest risk for contracting coronavirus and where transmissions is highest in the state.
Since the pandemic began, 10 Illinois schools have reported confirmed coronaviurs outbreaks and 478 have reported exposure, according to data from the Illinois Department of Public Health.
Of the over 5,000 schools in Illinois, 478 have reported potential COVID-19 exposures, meaning the schools are locations where the coronavirus may have occurred, but are not definitive exposure or outbreak locations.
"Anyone who goes into a school building regularly would have likely reported school as a place they went before they were confirmed positive – that doesn’t at all mean that school is where they contracted the disease originally," Pritzker said.
The outbreaks do not include secondary cases where a member of a household contracts the coronavirus but has not been on school grounds, according to Pritzker. However, he said the data does include cases associated with before and after school programs, such a sports.