As coronavirus rates rise to unprecedented levels in the United States, school officials are once again struggling with whether to allow schoolchildren into classrooms or to keep them home, trying to balance the needs of their most vulnerable charges with the risks a surging pandemic could pose to students and staff — all with little guidance from the federal government.

This week, New York City, once the epicenter of the pandemic and home to the nation’s largest school system, announced it would close its school buildings as positivity rates rose to 3 percent. Several districts in Iowa, where schools cannot shutter unless positivity rates reach 15 percent, have gone remote. Kentucky Gov. Andy Beshear (D) this week ordered all schools to close, and Michigan Gov. Gretchen Whitmer (D), has closed all high schools.

Dozens of districts, including those in Chicago, Sacramento and Minneapolis, remain closed and expressed dwindling hope of reopening anytime soon given the conditions. Seattle last week decided to keep schools closed until the end of January. Miami Superintendent Alberto Carvalho said earlier this week he was convening a task force to determine if the schools should shutter, as the number of new cases begins to rise. On Friday, Miami-Dade County reported more than 2,000 new cases.

The U.S. recorded more than 196,000 new coronavirus infections Friday, once again breaking the record for the most new infections on a single day. The death toll surpassed 250,000 on Thursday, marking another grim milestone. The pandemic shows little sign of slowing.

The spread in infection has meant that some districts that want to keep their doors open have so many staff out sick or in quarantine that they can no longer operate schools.

The wave of closures is running up against pressure from parents, governors and the Trump administration to keep schools open. A coalition of seven governors from northeastern states, including New York, put out a statement Thursday urging schools to keep their doors open.

“Medical research as well as data from Northeastern states, from across the country, and from around the world make it clear that in-person learning is safe when the appropriate protections are in place, even in communities with high transmission rates,” the statement read.

Schools that have held in-person classes have reported that even when they have cases of infection, they don’t believe there was spread in classrooms.

A day after New York City announced it was closing its schools, Vice President Pence held a coronavirus task force briefing — the first since July — to voice his support for keeping schools open, even as the pandemic worsens in many places.

“President Trump wanted me to make it clear that our task force, this administration and our president does not support another national lockdown and we do not support closing schools,” Pence said.

Robert Redfield, director of the Centers for Disease Control and Prevention, echoed Pence’s comments, saying he believed that schools could operate “safely and responsibly.”

“One of the safest place they can be, from our perspective, is to remain in school,” Redfield.

Trump began his campaign to reopen schools in midsummer, blasting those who chose to keep them closed as trying to undermine him politically, threatening to withhold funding from districts that did not reopen, and openly disagreeing with recommendations laid out by his own public health department. His tack, frequently delivering his messages in all caps over Twitter, backfired, leading some school officials to grow suspect of the administration’s recommendations.

But now, other voices have joined the call to reopen schools. They include critics who have begun questioning why some places have shut down schools but left open bars and restaurants. And the widespread school outbreaks that many feared have largely not materialized, according to existing data, leading some to say that students and teachers are unlikely to catch the virus in school — particularly if they are masked.

School officials who want to keep their schools open — and believe that they are safe — are running into another barrier. In some cases, so many teachers are out sick or quarantined that there are not enough to supervise students. It’s a conundrum that has forced schools in rural North Dakota and Illinois to shut down.

PJ Caposey, who leads a small school district about 90 miles west of Chicago, said he believes his schools are safe, and sends his own children in to school buildings. Under the current model, elementary school children can attend classes every day, whereas middle and high school students attend only part of the week and learn virtually the rest of the time.

But his staff is stretched so thin that secretaries are sometimes playing substitute teachers. He had to shut down one school because they could not find enough adults to run it. As of Friday, he had 27 staff members in quarantine.

Ogle County, where his district is based, has been averaging more than 50 new cases a day over the last week — an astonishing figure for a county of about 50,000 people. Friday, after pleas from the health department and local hospitals, he agreed to close school buildings from Thanksgiving until mid-January. Parents in the conservative county were furious, he said.

“Now we’re just at a point that regionally that it’s so out of control here we don’t really have a choice,” Caposey said.

Robin Lake, director of the Center on Reinventing Public Education, anticipated more school districts would follow New York City’s footsteps. The center has been closely monitoring how schools respond to coronavirus, and in an analysis released earlier this month, found that schools were trending toward reopening. She expects a reversal of that.

“When a big district like New York City reverses course, other districts look at that and think, ‘Well, if they can’t do it, maybe we can’t either,’ ” Lake said.

So much of the dialogue has been about whether schools should reopen — and Lake said that some school districts may have to accept that it is not in the cards, and plan for more robust virtual learning.

Erika Kendall, a Brooklyn mother and school activist who heads her local school advisory council, said conversation and resources need to shift to how the New York City school system can improve virtual learning. Families that opted for remote learning are disproportionately Black, Asian and Latino — a reflection, to some extent, of the trauma the pandemic wrought on their communities.

She said there are plenty of benefits for children to be in school buildings, but “it’s not going to be easy to translate that by remote.”

“But how can you get as close as possible if we’re constantly obsessing over getting every child back in the building,” Kendall said. “We can’t ever really have that conversation.”