Pritzker said a Will County resident in his 50s, a Cook County resident in her 80s and a Florida resident in her 70s died after being diagnosed with COVID-19.
The Florida resident was visiting downstate Sangamon County, near Springfield, according to health officials.
"My heart goes out to the family, the friends of these patients. And I feel like I can speak for all of Illinois when I say we offer them our collective strength at this time," the governor said.
Illinois health officials said none of the deaths are connected to a nursing home.
"This coronavirus is an equal opportunity virus, no respecter of age, person, zip code, gender. It can infect anyone. And even healthy people," said Illinois Department of Public Health Dr. Ngozi Ezike.
Health officials announced Thursday the number of cases statewide has risen to 422, a spike from the 288 total a day before.
There are now cases in 22 counties, with patients' ages ranging from 9 to 99.
The five new counties that are now reporting coronavirus cases include Jackson, Kankakee, LaSalle, Washington and Williamson counties.
Health officials said the increase in cases reported is partly due to more testing by commercial and hospital labs. More than 1,000 people in the state are being tested daily, with hopes of doubling that number in the coming days.
Gov. Pritzker said Thursday that he's not ready to institute a wider shelter in place order.
But with other states, including Indiana, and now Chicago Public Schools extending school closures into April, might Illinois follow suit?
"We're obviously evaluating that every day," Pritzker said. "I would say to parents that they should obviously be planning for the possibility that there would be an extension of that date, but right now we're sticking with the March 31st date."
The governor also announced an economic relief package for small business owners, including a two-month delay in sales tax payments for small and medium-sized bars and restaurants.
In need of more hospital beds, officials are considering reopening shuttered hospitals or perhaps building a field hospital. It requires time, so slowing the virus' spread is critical.
FIRST RESPONDERS REMAIN ON FRONT LINES DURING CORONAVIRUS CRISIS
At the front lines of the COVID-19 pandemic, first responders are worried that the federal guidelines put in place to keep them at work and healthy are doing just the opposite.
"Obviously there's is a lot of concern out there. There's a lot of concern from providers," said Dr. Trevor Lewis, interim chair of emergency medicine at Cook County Health.
Chicago-area doctors and nurses are desperately trying to test and treat those exposed to the virus while staying health at the same time.
"Our providers show up with a mask in place," Dr. Lewis said.
The threat of a medical supply shortage looms over those who need it most.
"CDC guidelines are saying that as we run out of equipment and if it comes to the point where we don't have any masks available that using scarfs or bandanas would be appropriate to protect us which is absolutely ridiculous," said Simia Rodriguez, a Registered Nurse at AMITA St. Joseph Medical Center.
Joliet nurse Simia Rodriguez said it will only be a matter of time before the virus impacts the most valuable players in treating this virus.
"This is exactly what were here for but no one should be made to do any of this without the proper protection in place," Rodriguez said.
LONG-TERM CARE FACILITIES ACROSS ILLINOIS HIT BY COVID-19 OUTBREAK
Earlier this week, Illinois health officials an outbreak at a DuPage County nursing home.
On Wednesday, health officials announced two dozen additional cases at the Chateau Nursing and Rehabilitation Center in Willowbrook.
DuPage County officials said they began testing at the facility after a woman in her 60s tested positive on Saturday.
Eighteen residents and four staff members were confirmed to have the virus on Tuesday.
The total cases linked to the long-term care facility is 42: 30 residents and 12 staff.
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In announcing the sharp increase in the number of Illinois cases, officials made yet another appeal for people to stay at home, saying seniors need to rely on community members to bring them what they need and young people and parents need to act responsibly.
"If you're a kid, and you're home from school, which is all of our kids, don't undermine the school closures by now creating play dates with a bunch of your friends that you would have been with at school. That just negates the benefit of the school closure," IDPH Dr. Ngozi Ezike said.
For weeks, officials have been asking privately owned senior homes, and mandating state-owned facilities, to limit visitors and take extensive action to pre-screen employees.
Officials said that first resident diagnosed Saturday had been symptomatic for a few days.
At a news conference on Tuesday, Pritzker announced the first novel coronavirus-related death in the state, saying it's the news he has dreaded since the earliest days of this outbreak.
Patricia Frieson, 61, of Chicago's Auburn Gresham neighborhood, was being treated at the University of Chicago Medical Center, where she later died.
Frieson's family said she was not a nursing home resident but did have asthma.
Officials said she had underlying health conditions and had contact with another COVID-19 case.
Her brother said he doesn't know how she caught the virus.
"We weren't allowed to be there because of the situation and the possible contagiousness of the disease," he said. "When we could talk to her she said she seemed to be getting better and then it got worse. That's all we really know because we couldn't be there every day for her."
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Pritzker said Wednesday that his office has been in contact with sheriff's departments across the state, asking them to suspend the enforcement of eviction notices.
He's also asking the state's utilities to suspend any shutoffs because of lack of payment.
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About 60 service members from the Illinois National Guard have been activated. Officials said they will help with logistical support and medical staffing.
The Illinois Department of Public Health has created a hotline at 1-800-889-3931. More information can be found at the IDPH website and the Chicago Department of Public Health website.