WATCH: Gov. JB Pritzker gives virtual COVID-19 update on May 11
The news comes as Illinois health officials announced 1,266 new cases of COVID-19, including 54 additional deaths, on Monday. That brings the statewide total to 79,007 cases, including 3,459 deaths.
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Delivering Monday's COVID-19 update from his Gold Coast mansion, the governor said the unnamed senior staffer was one of about 20 members of his team who'd been working inside the Thompson Center.
"For the time being, and I want to assure everyone that the governor's office is very much still in full operation, and all aspects of the executive branch will function as they have been," Gov. JB Pritzker said.
After the entire staff was tested last week as a precaution, that person was diagnosed on Saturday and is still asymptomatic. The governor said he tested negatively as recently as Sunday.
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"I don't have regular every day contact with that person directly, although that person would sometimes, would every day, sit in a large meeting room where we were all socially-distancing," Pritzker said.
The 15th and 16th floors of the Thomson Center will now undergo a deep cleaning.
WATCH: Illinois COVID-19 peak extended into mid-June
Illinois' two top Republican lawmakers sent a letter to Gov. Pritzker Monday asking him to revise his reopening guidelines to allow for just 14 days between phases as touted by the Illinois Municipal League and the White House.
"Their guidance would have required 14 days of a decline in the numbers," Pritzker said. "And what we require is simply following a flattened number for 28 days."
Pritzker updated some of the metrics that will determine how quickly the economy reopens. He said all four regions are on track for a May 29 move to Phase 3. But he said the northeast region, which covers the Chicago area, continues to see a positivity rate above 22 percent and needs to be below 20. With the curve flattening, it's extending our peak.
"That time frame of plateauing near a peak has been extended from mid-May into mid-June," Pritzker said.
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With protesters and even a Chicago church pushing back on Illinois stay-at-home order over the weekend, Gov. JB Pritzker defended his cautious reopening plan during an interview on CNN Sunday.
"We are being very careful. We have a 28-day period that we're in now during the month of May, in which we're watching all these numbers. Monitoring them, " Pritzker said.
The governor said Illinois officials have "done a lot to make sure that we're keeping these numbers moving in the right direction."
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"We will not reopen unless we meet all of the standards that I've set for doing so," Pritzker said.
The governor also announced that he put together a group with the state health department to track cases of children with an illness possibly linked to COVID-19.
He added that the state plans to launch a massive contact tracing effort in the next few weeks.
WATCH: Chicago area hospitals to receive 90% of Illinois' Remdesivir supply
Illinois received its first shipment of Remdesivir, the anti-viral drug showing promise in lessening COVID-19 symptoms, over the weekend. The relatively small shipment of 140 cases was distributed to 14 hospitals and is enough to treat around 700 patients.
One doctor called it the best thing we have going right now in the fight to contain COVID19. It's by no means a cure, but doctors say Remdesivir is a relief.
"If I had COVID-19, there's no question I'd want to have this for myself because I know the downside is minimal," said Dr. Richard Novak, chief of infectious diseases at University of Illinois-Chicago.
Administered by IV, the anti-viral drug is designed to stop the virus from replicating. And based on studies, doctors say it appears to be working.
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A memo from the state health department shows 90% of the shipment is going to Chicago area hospitals, with Advocate Christ Medical Center in Oak Lawn and RUSH University Medical Center getting the most.
Dr. Shivanjali Shankaran, assistant professor of infectious diseases at RUSH, said the drug aims to "decrease the fever, but mainly to decrease the amount of inflammation in the lungs and therefore the amount of oxygen patients require."
Doctors said the shipment of the experimental drug from the federal government will allow hundreds of Chicago area COVID patients a better shot at a faster recovery.
"It was distributed to hospitals that have seen the most critically-ill COVID-19 patients," Dr. Ezike said. "We also included safety net hospitals and hospitals treating large communities of color to address the equity aspect."
"We can't just give it to everybody because we just don't have very much," Dr. Novak said. "We want to give it to people with the best chance of recovery, and the other advantage to that is that we might be able to get by with a shorter course, people who are not as severely ill.
But some doctors feel deciding who is most deserving of the drug puts medical professionals in an ethical bind.
"I think since the beginning the ethics of how we decide who gets treated has been an issue and everyone is trying to grapple with that, so we came up with criteria that based on evidence we have," Shankaran said. "The patient's going to be involved in the decision-making so they know that there are alternatives."
And doctors hope to be able to offer the drug to more patients soon enough.
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 websiteid