City officials said Thursday they feel comfortable moving forward in planning for a phased-in return to Chicago Public Schools classrooms despite a dramatic rise in COVID-19 infections that has pushed the city and state to record-high virus spread.

Mayor Lori Lightfoot and city health commissioner Dr. Allison Arwady painted a grim picture of the city’s pandemic outlook at a news briefing Thursday, saying the situation is worse today than it was in its darkest days in the spring. Even so, Lightfoot and Arwady said they remain confident they can safely send students and teachers back to schools “when the time is appropriate.”

The district announced plans last month to send preschool and some special education students back to classrooms sometime during the second academic quarter that starts Monday, but no return is expected next week. Neither the mayor nor Arwady would set a date for a potential return.

“As I’ve said before, this to me is a balancing two things, but it’s primarily a balancing around equity,” Lightfoot said. “We know that some children learn just fine through remote learning, but we also know that some do not at all. And I worry very much every single day that they are falling behind.

“We’ve got to start thinking about a path to get those kids who are falling behind back into school, and that’s precisely what’s happening.”

Lightfoot repeated her stance that the city would be “guided by the science” and would not “do anything that puts kids in harm’s way,” but it was notable that the mayor’s messaging on schools did not change in the face of otherwise increasingly dire public health circumstances.

Chicago has far surpassed thresholds set by Arwady in July — seven-day rolling averages of 400 new daily cases and 8% test positivity — that she declared would have led to continued school closures. The latest figures reported by the Chicago Department of Public Health put the city at an average of 1,395 daily cases and 10.9% positivity. Illinois on Thursday passed the 10,000-death mark and reported a staggering 9,935 new COVID-19 cases, dwarfing the previous high of 7,899 set last Saturday.

Arwady said new data in the months since she set those thresholds has shown minimal coronavirus spread in schools and bucked her expectations. She also noted Catholic and other private schools in the city have been operating in-person classes this fall “and that has gone remarkably well from a COVID perspective” — though there are splits in the needs of student populations at CPS compared to private schools.

“We’ve learned a lot since June when we were initially laying that out, and I feel much more comfortable with the idea of in-person education if the appropriate precautions and protocols are in place,” Arwady said. “Certainly, we are also watching this increase with concern, and we are in conversations about what would be appropriate in terms of timing.”

CPS said Wednesday that ventilation and air quality inspections done over the past few weeks show 91% of classrooms citywide are safe for students and teachers, and air purifiers would be purchased for all rooms.

The Chicago Teachers Union has strongly opposed a return to schools and last month filed for an injunction against CPS to delay plans to resume in-person learning. The union accused the district of failing to bargain in good faith on safe working conditions and moving ahead with a reopening without coming to an agreement with the CTU.

The Illinois Educational Labor Relations Board ruled at a hearing in that case Thursday that CPS did not violate labor law because a specific date for a return had not been set. The school system would only need to negotiate once a return date is identified, the board ruled.