Her diagnosis came less than 24 hours after she helped seal a deal to send Chicago Public Schools students back to the classroom.
"Earlier today, I tested positive for COVID-19," the mayor tweeted Tuesday afternoon. "I am experiencing cold-like symptoms but otherwise feel fine which I credit to being vaccinated and boosted. I will continue to work from home while following the CDC guidelines for isolation."
Earlier today, I tested positive for COVID-19. I am experiencing cold-like symptoms but otherwise feel fine which I credit to being vaccinated and boosted. I will continue to work from home while following the CDC guidelines for isolation.— Mayor Lori E. Lightfoot (@chicagosmayor) January 11, 2022
Her case is part of the surge that has been taking place across the area, and she will not be working at City Hall for at least the next few days while she recovers.
The mayor's last public appearance was at a press conference Monday night announcing the end of the standoff between Chicago Public Schools and the Chicago Teachers Union over remote learning and COVID safety metrics. She was in close proximity with CPS CEO Pedro Martinez.
Lightfoot, 59, was also in close proximity to Chicago Department of Public Health Commissioner Dr. Allison Arwady during the CTU and CPS standoff. The Chicago Department of Public Health released a statement Tuesday, saying, "Dr. Arwady feels fine and she continues to take precautions such as masking and social distancing. But as she's fully vaccinated and boosted, she does not need to quarantine after a possible close contact exposure. She will continue to monitor for any symptoms and follow the public health guidance. The COVID-19 vaccines provide great protection against severe outcomes, and she's hopeful people will use this news to get vaccinated and boosted."
Before Monday's news conference, Lightfoot also spoke at a South Side memorial service for well-known funeral director Lafayette Gatling.
The mayor's office declined to say exactly when Lightfoot started feeling symptoms, how many people she'd been in contact with or whether other staffers will take further precautions.
Lightfoot's communications director noted the office is following CDC guidance for fully vaccinated and boosted people, who aren't required to stay home after a close contact unless they develop symptoms. They are, however, urged to get tested in five days, watch for symptoms for at least 10 days and wear a well-fitting mask whenever they're around others.
Lightfoot received her booster shot on Nov. 12, during a citywide "vaccination awareness day" before the emergence of the highly contagious omicron variant.
She is among almost a quarter-million Illinois residents who have tested positive for the virus over the past week, including a growing number of elected officials. U.S. Representatives Bobby Rush and Sean Casten have each tested positive, as has Lt. Gov. Juliana Stratton.
On Tuesday afternoon, Gov. JB Pritzker tweeted his "best wishes for a full and speedy recovery" to Lightfoot.
Sending my best wishes for a full and speedy recovery to @chicagosmayor.— Governor JB Pritzker (@GovPritzker) January 11, 2022
I encourage all Illinoisans to follow in the Mayor’s footsteps and get vaccinated, get boosted, and get tested — it’s how we bring this pandemic to an end. https://t.co/ne9b0CObTL
Illinois reported 28,110 new COVID-19 cases Tuesday and 92 related deaths. The statewide positivity rate is 16.9%.
RELATED: Illinois reports 28,110 new cases, 92 deaths
Chicago COVID cases have been surging for two straight weeks.
"I'm less concerned than I was even three or four days ago about where we are but I'm still concerned about the hospitals," said Arwady. "This hopeful flattening that we are seeing right now, I've got to see it for at least a week to really trust it. "This is still a very bad surge, and I don't want people to think otherwise. And I really don't want people to think sort of it's over; it is extremely not over."
Health officials in the city and state have stressed the importance of getting vaccinated and boosted in order to fight COVID and omicron. Health officials have noted that the vast majority of severe cases, hospitalizations and deaths have been in unvaccinated patients.
"We continue to see the COVID-19 vaccine provide great protection against serious outcomes - specifically hospitalization and death," Arwady said. "Especially in the colder months and through the current Omicron surge, it is so important that all eligible members of your family have received their COVID-19 vaccine and booster."
RELATD: Chicago to distribute 1.5M KN95 face masks across city
The Chicago Office of Emergency Management and CDPH worked to distribute 1.5 million KN95 masks across the city Tuesday, available at aldermanic offices for constituents and community groups.
The wave of omicron variant infections in the city, state and country has intensified steadily through the winter.
Sun-Times Media contributed to this report.