CHICAGO (CBS) — The target date for Chicago Public Schools high school students to return to class is less than two weeks away.

Talks between CPS and the Chicago Teachers Union about making that happen continued on Tuesday. But as CBS 2 Political Investigator Dana Kozlov reported, there could be a new sticking point.

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While the target return date of Monday, April 19, has not changed, the COVID-19 positivity rate in Chicago has changed since it was announced – and not for better.

It has gone up 2 percent in just the past couple of weeks, especially among young people. That rising rate could have a big impact on the ongoing negotiations.

As of Tuesday, it had been a month since grade schoolers who opted for in-person learning have been back in Chicago Public Schools classrooms. That comes after weeks of contentious negotiations between CPS and the union.

The tone of high school reopening talks is different.

“I feel confident that we’re going to meet that date, given the way that conversations have been going,” CPS Chief Executive Officer Dr. Janice Jackson said on March 17.

“I’m confident that we’re going to be able to get high school back, but like, you know, I’m also confident that it’s not going to look like just like normal school,” CTU President Jesse Sharkey said on March 10. “We’re going to have to keep the safety parts of it in mind.”

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Still, safety is a potential sticking point when it comes to how – or even if – high school students will return on April 19. Sources said besides the rising COVID rates, vaccine access for teachers, students, and their vulnerable family members are still critical to an agreement.

And even though sources said both sides have not agreed on anything, some high school students were getting emails on Tuesday telling them what days they will head into the classroom in two weeks.

CPS is proposing three models depending on school enrollment, the percentage of returning students, and social distancing space per school. Based on that, students could return four days a week at smaller high schools, two days a week in two groups at others, and one day a week at larger schools.

But again, sources said no deal about any specifics has yet been struck.

Another issue that may impact an agreement is allowing all students and staff to remain remote one day a week. That is something CPS has been reluctant to allow at this point.

The hope is that talks will not turn contentious as CPS’ imposed return date approaches, as they did during earlier negotiations about reopening. But there is always a possibility that they will if both sides don’t start agreeing on issues soon.

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However, a mediator is involved this time around, which could help keep the temperature down as the talks remain ongoing throughout the rest of the week and beyond.