CHICAGO (CBS) — A senior staffer for Gov. JB Pritzker has tested positive for the novel coronavirus, prompting the governor and approximately 20 employees to start working from home.

According to the governor’s office, an asymptomatic staff member tested positive for COVID-19 late last week and the governor’s office found out on Saturday.

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“I was in contact with that person today. That person is still asymptomatic, and so feeling fine, although obviously, it’s an anxious-ridden moment for that person just to know that they’ve tested positive,” Pritzker said.

Pritzker himself and other staff members who have been around the infected staffer have all tested negative for the virus. Pritzker was tested again on Sunday, and again tested negative. Illinois Department of Public Health Director Dr. Ngozi Ezike, who speaks at the governor’s daily briefings, also tested negative last week.

The staffer who tested positive, Pritzker told reporters, worked in a careful environment.

“They work on same floor, down the hall – I don’t know how many feet, but a number of feet down the hall from me. I don’t have regular, everyday contact with that person directly, although that person would sometimes, would every day sit in large meeting room where we were all socially distancing,” Pritzker said.

The governor said privacy concerns prevented him from revealing the staff member’s identity, but he or she is not showing symptoms of COVID-19.

About 20 staffers who had been working from the Thompson Center during the outbreak are now working from home, along with the rest of the governor’s office staff, who had been doing so already.

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Staffers who had been working at the Thompson Center during the COVID-19 crisis had been undergoing daily temperature checks, wearing masks, and following strict social distancing guidelines, according to the governor’s office.

The governor’s offices at the Thompson Center will be deep cleaned, and staff will monitor their symptoms from home until the Illinois Department of Public Health determines it’s safe for them to return to the office.

Pritzker also will continue to hold daily press briefings via video conference.

Gov. Pritzker and his aides will have to monitor their health over the next two weeks, said Northwestern Medicine’s Dr. Irfan Hafiz.

“It’s s really that 14 days of incubation and that quarantine that’s important there, and if you get through the 14 days without symptoms or any positive tests, then you’re out of the woods,” Hafiz told CBS 2’s Jim Williams.

The governor, who was last tested on Sunday, said he’s not out of town – he’s at his home in Chicago.

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The governor’s office said the staffer who tested positive for the virus has not worked in the room where the governor has been holding daily briefings, so would not have had contact with the reporters and photographers covering those events.