With Philadelphia in the grip of a dangerous COVID-19 surge, the city’s public school system on Tuesday reversed its plan to start bringing students and staff back to classrooms later this month.

Superintendent William R. Hite Jr. said he made the call to indefinitely continue virtual instruction “to help safeguard the health and well-being of our staff, students, and school communities.”

Pre-kindergarten through second-grade students were supposed to return to school Nov. 30, with teachers in those grades scheduled to report Monday to begin readying classrooms for them.

Philadelphia Health Commissioner Thomas Farley said he did not order the closure but had kept close contact with district officials and fully supported the decision.

“There’s no question we are in a dangerous period,” Farley said at a news conference. Case counts in the city are at an all-time high, with an average of 515 new coronavirus infections per day in the last week. Nearly 50,000 Philadelphians have been diagnosed with COVID-19 since the pandemic began, and 1,901 have died from the virus.

Hite has long said that he wants children, particularly the city’s youngest learners, to have the option to return to school as soon as possible. But as the days wore on, it became clear that the Nov. 30 date was no longer realistic.

“There is a concern that those numbers will only rise in the coming weeks as people gather for the holidays, the weather gets colder, and the air gets drier,” the superintendent said.

Still, Hite said he realized the decision “is disappointing for many families and many students” and disproportionately affects children living in poverty and children of color.

“We wanted to make sure that children had the appropriate conditions for learning to read, learning to do math,” Hite said. “Unfortunately, in many of our communities, those conditions do not exist, and that’s why we were doing our best to get kids back as soon as possible.”

Abandoning the Nov. 30 reopening affects about 10,000 students. In all, 32,000 children had been eligible to return to school at the end of the month, but of those, two-thirds had opted to stay home full-time.

Now, all 120,000 district students will remain home indefinitely, though Hite said the school system hopes children can return to buildings eventually. That call will be made "only when guidance and data from the Philadelphia Department of Public Health, [the Pennsylvania Department of Education] and the Pennsylvania Department of Health indicates that we can do so.”

For now, school employees who have been working from buildings, including principals and some support staff, are permitted to continue doing so.

Tuesday’s announcement could also push back the return to school of students with complex needs, such as some special-education students and English-language learners, who were scheduled to return in January, and ninth graders and vocational students, who were supposed to come back in February.

The district still has no timetable for when the majority of its pupils, those in third through 12th grades, will return to school. Hite has said it’s possible they might not be able to return in the 2020-21 school year.

The Philadelphia Federation of Teachers had opposed any return to schools amid the current COVID spike. PFT president Jerry Jordan hailed the district’s decision as a “big victory.”

“The decision to remain fully virtual for the foreseeable future will save lives,” Jordan said in a statement. “The science of COVID-19, paired with the massive ventilation and other facilities issues throughout the District, makes it clear: Returning to school buildings, in any capacity, is unsafe right now.”

Many rooms in the district’s stock of aging buildings have inadequate ventilation to safely support even 15 people in a classroom. Officials said that they would continue working on ventilation issues while schools remained closed to in-person instruction, and that rooms that couldn’t be fixed would not be used.

Philadelphia’s decision to remain fully virtual indefinitely comes as schools around the region grapple with the virus spike.

Less than 24 hours before its students were set to return to school two days a week, Cherry Hill public schools on Monday night made the decision to remain virtual through Nov. 30 because of a high number of new COVID-19 cases among school-aged children in the township.

The LEAP Academy University Charter School in Camden also announced Tuesday that it has closed its campus for in-person instruction after someone there tested positive for COVID-19.

The sprawling campus, which enrolls more than 1,500 students in pre-K through 12th grade, will shift to remote learning until Nov. 24, said spokesperson Adam Dvorin. The school’s six buildings on Cooper Street in downtown Camden were closed as a precaution after a discussion with health officials, he said.

“The care and safety of LEAP students and staff remains a priority,” Dvorin said in a statement.

Staff writer Melanie Burney contributed to this article.