CHICAGO (CBS) — Negotiations continued Saturday between the Chicago Public Schools and the Chicago Teachers Union over concerns about a return to in-person learning and COVID-19 transmission – but there had been no resolution as of the evening.

In a joint statement Saturday evening, Mayor Lori Lightfoot and CPS Chief Executive Officer Dr. Janice Jackson said: “The parties have been in discussions throughout the course of the day to determine if there is a pathway toward a final, comprehensive deal. Those discussions continue.”

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This comes a day after Mayor Lightfoot and CPS told some teachers and staff to be back in school buildings on Monday, or get locked out. If the district follows through on that threat, it likely would trigger another teachers’ strike, the second since Lightfoot took office.

On Friday, Lightfoot and Jackson told the CTU they had made their “last, best, and final offer” in the stalemate over reopening schools. But it was soon clear that final offer well short of what the union wanted, to get teachers back in classrooms next week.

In a letter sent to CPS parents and staff Friday evening, school district leaders explained out that there still is no agreement, and said they have called on pre-k and special education cluster teachers to show up to school buildings on Monday unless they’ve been approved to work remote. Those who fail to report will be considered absent without leave, and locked out from CPS systems at the end of the day.

The union has said such a move could trigger a district-wide strike, if a majority of the CTU House of Delegates approved one.

As the two sides released details and objections, we learned a lot about the fine print on what’s keeping them apart.

CPS is offering 1,500 vaccinations for CPS staff per week, but the union feels that’s insufficient.

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Another sticking point is what would trigger future school closings if there’s a COVID outbreak in schools. The city’s offer would close schools again only if a 2.5% rate is detected from select schools, rejecting a more stringent CDC closing plan.

The two sides also have yet to agree on how to accommodate teachers who wish to continue working remotely. The union has said the CPS has rejected 75% of requests by members to work from home because of heightened COVID risks personally or in their household.

The mayor tried to reframe their requests in a video released Friday afternoon on social media.

“In order to implement CTU’s plan, we would have to stop vaccine distribution across the entire city for everyone else. Literally,” the mayor said.

Until Friday, neither side had gone into great depth in public about where they fell on the remaining sticking points.

Meantime, CPS has offered a new schedule for returning students to classrooms. Their proposal would have pre-kindergarten and special education students back on Tuesday, with their teachers back Monday. Kindergarten through 5th grade students would go back on Feb. 22, with their teachers back on Feb. 16. Grades 6 through 8 would return March 1, with their teachers back on Feb. 22.

“We’re deeply disappointed that the mayor has chosen to stop negotiating and instead move to lock out educators and shut down schools rather than work out our differences,” CTU President Jesse Sharkey said in a statement Friday afternoon.

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