The Philadelphia School District is likely to require COVID-19 vaccinations for all of its 20,000-plus employees, but that mandate won’t be in place by the start of the school year.

With six separate unions, emergency FDA approval of the vaccines, and no clear way to know who has already received shots, Superintendent William R. Hite Jr. said it will take more time to work out the mechanics of a mandate.

“I do think at some point during the school year, there will be a mandate for all employees to be vaccinated,” he said.

Hite has urged employees and eligible students to get vaccinated for months. Nationally, about 90% of American Federation of Teachers members are vaccinated, and Philadelphia’s numbers are believed to be about the same.

“I believe everyone in the district who can be vaccinated should be,” the superintendent said in a meeting with The Inquirer Editorial Board.

Philadelphia would not be the first local school system to mandate vaccination — Upper Merion has moved to require all staff to either be vaccinated or have multiple weekly COVID-19 tests — but it would be the largest system in the region to do so.

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Philadelphia students are set to return to classrooms Aug. 31. For many, it will be the first in-person education since March 2020. The district offered some classroom instruction last spring, but most families chose to keep their children fully virtual.

The Philadelphia Federation of Teachers, the school system’s largest union, has expressed support for a vaccine mandate, but PFT president Jerry Jordan said there’s been no outreach or negotiation beyond a phone call after Hite discussed the possibility at a news conference.

“The fact that we have very clearly shared our support for a negotiated mandate and yet the district has yet to formally ask for one is simply absurd,” Jordan said in a statement. “The clock is ticking.”

When school begins, the vast majority of Philadelphia students will attend classes in person, despite the delta variant and rise in COVID-19 cases. Just 2,600 new students have signed up for the district’s fully virtual option, now open to children in kindergarten through 12th grade.

Overall, the Philadelphia Virtual Academy is projecting an enrollment of 4,000, including new students. The online school had been open to sixth through 12th graders since 2013, but was expanded to include all district students for this year.

PVA students will receive no real-time instruction, but will have asynchronous lessons and teacher support. That’s very different from last year’s remote option, where students remained enrolled in their home school, taught by their classroom teachers in real time. To sign up for PVA, children had to give up their seats in their regular schools.

Many families “are not enamored with that model,” Hite said.

And while virtual enrollment is 4,000 now, less than 5% of the district’s 120,000 students, “we are pretty confident that number is going to decrease as families learn more about what that option means,” Hite said.

The superintendent also affirmed that the district’s controversial new schedules are fixed for this school year.

The district is moving to three standard start times, from the prior 30 different times. The shift, which communities have said was abruptly announced, moves some middle and high school start times earlier, counter to scientific research that shows adolescents should start school later. It also puts some parents in a bind for child care.

A growing, nationwide bus-driver shortage factored into the schedule changes, Hite said. Of the district’s 200-plus schools, 190 had schedule shifts of less than 30 minutes, Hite said, and 27 and no schedule changes at all.

Of those K-8 schools whose start times moved earlier, the district is offering support to families, either in the form of outside organizations providing on-site child care or school staff watching children. Both options will be free, Hite said.

Though the schedules are set for the 2021-22 school year, more are likely going forward, the superintendent said.