President Biden campaigned on a promise to reopen schools and said guidelines from the Centers for Disease Control and Prevention would help make it happen. That guidance is out, but in many communities, it is doing more to keep schools at least partially closed.

That’s because in areas with high infection rates — most of the country — the CDC recommends that school buildings open with a fraction of students in the building, or remain closed altogether.

The guidelines offer a detailed road map for precautions needed to open safely, but they also have led to confusion over whether the federal government is encouraging schools to open or not.

“We expected this to be a little bit more of a spark toward reopening,” said Sasha Pudelski, advocacy director for AASA, the School Superintendents Association. “In some places it is making the conversations more difficult.”

Some districts are ignoring the CDC altogether. In Los Angeles, for instance, the superintendent says he will wait to reopen until teachers are vaccinated, something the CDC says is not necessary. In others, they are proceeding with full-time school without the precautions the agency recommends.

And some districts are ratcheting back plans to reopen, citing the CDC.

“Our earlier plans did not reflect the new CDC guidelines,” said Ray Weikal, a spokesman for Kansas City, Mo., schools, which had planned to return to full-time, in-person classes. Then the CDC guidelines came out recommending that communities in areas with high infection rates maintain a strict six feet of distance between people. Kansas City was in the “red zone,” the worst of four zones.

Kansas City now plans to use a hybrid model, where students are in school part time and learning from home the rest of the time. And the district decided to slow down its schedule. Grades 10 through 12 are now not scheduled to return until April.

“We’re just adapting,” Weikal said.

Reopening schools is a key factor for Americans longing for a return to normalcy, nearly a year after students were sent home for what they thought would be a few weeks of virtual learning. As a candidate and repeatedly as president, Biden has said this is one of his top goals and vowed to reopen most schools within 100 days of taking office.

The CDC guidelines were seen as a critical step. Teachers, parents and politicians have debated, sometimes fiercely, the right path. The hope was that the CDC, the world’s premier public health agency, would lay out a compelling road map forward for how to open safely that could rise above the battles.

Too cautious, not cautious enough

Many welcomed the document as a huge step forward from the Trump administration, but it has been criticized as both too cautious and not cautious enough.

Some say the agency’s focus on ensuring six feet of distance between people in buildings is too tough, and that three feet is sufficient. Others say the agency was wrong not to emphasize the need for better ventilation or more screening in schools. And many say the guidelines are simply too confusing to follow.

Taken together, these concerns are serving to slow the reopening process in some communities, keeping students home or in “hybrid” programs in which they are in school buildings some of the time and at home sometimes. That could be a problem for Biden, who has said he wants students back five days a week.

Overall, the CDC has said there is scant transmission of the virus inside schools when mitigation measures are followed, particularly mandatory masks and distancing inside buildings. But agency officials say the risk in schools is higher when community infection rates are higher. So the guidelines urge districts to employ hybrid learning for elementary schools when rates are high, and either hybrid with strict rules or fully remote for middle and high schools.

“There are opportunities for in-person learning at all stages, all states of community spread,” CDC Director Rochelle Walensky said last week when asked how Biden can meet his goal of reopening. She added that with infection rates coming down, schools are leaving the red zone, which has the most restrictive recommendations. “Our numbers are coming down, and I would actually invite schools to lean in and to look at what is needed . . . to try and get more and more children back to school.”

As of Sunday, about 72 percent of K-12 students attend a school district in a red zone, with “high” transmission, according to Burbio, a data service that tracks reopenings. Another 22 percent are in an area of “substantial” transmission, labeled orange. Only about 5 percent are in either of the lowest two levels.

A Pew Research Center survey released this week found that Americans’ concerns about education have shifted and people are now more worried about lost learning than the risks of return.

In July, about 6 in 10 people said schools should give a lot of consideration to the risks to students and to teachers as they decide whether to reopen. At the time, less than half said schools should give a lot of consideration to the possibility that students will fall behind academically without in-person instruction.

But asked the same question this month, the ratios were reversed, with 61 percent concerned about students falling behind and less than half worried about risks.

To be sure, the number of students being offered at least some in-person learning is on the rise. Burbio tracking, which is based on a sample of districts, shows 31 percent of K-12 students are in districts that are 100 percent virtual, down from 34 percent last week and 55 percent at the beginning of 2021.

And some officials are pushing for full-time school even now, including Massachusetts Gov. Charlie Baker (R), who this week proposed forcing elementary and middle schools to reopen five days a week starting in April. Officials cited the academic and emotional impacts on students of being out of schools and the drop in coronavirus cases.

But many school districts are moving slowly to reopen, driven by concerns of teachers and some families, as well as the guidelines. Some teachers have argued they should not return until all educators are vaccinated, although the CDC said this should not be a prerequisite.

Most plan hybrid model

At least a half-dozen large school systems plan to reopen classrooms next week, with more scheduled for the weeks to come. Almost all of them plan a hybrid model.

In Loudoun County, Va., the school district is phasing students back into schools for, at most, two days a week. Interim superintendent Scott Ziegler this week told the school board that the district cannot expand that to full time while adhering to the CDC guidelines. He expressed frustration that the guidelines call for six feet between students rather than three feet, as recommended by the state.

“I am very frustrated by the guidance that comes out that is not clear, that seems to contradict guidance that has been out previously and doesn’t incorporate the latest things known about covid,” he said.

“It’s interesting,” said Jeff Morse, a member of the Loudoun school board. “CDC, the more that they provide guidance, the worse the guidance gets and the more unclear it becomes.”

After seeing the CDC guidelines, the private University of Chicago Laboratory Schools ratcheted back plans for a full reopening to a hybrid plan for its lower school. The school said it was prepared to maintain five feet of distance between students, but not six feet. Angry parents planned a march on campus in protest, and a petition garnered more than 500 signatures.

The frustration was driven by the fact that the school had consulted with experts at the university and concluded five feet of distancing was safe, only to backtrack after the CDC guidelines were published, said Scott Gehlbach, a political scientist at the university whose third-grade son is enrolled at the Lab School.

“People are really frustrated and in some cases quite angry and determined to do what they can to get kids back to school,” he said.

On Wednesday, after the outcry, the school reversed its decision.

In other cases, the guidelines have reinforced cautious instincts already in place.

Jeanné Collins, superintendent of the Rutland Northeast Supervisory Union school district in Vermont, said the CDC regulations validated the district’s decision to keep middle and high school students at home three days a week and in school for two.

“We’re not ready to bring in our middle school and high school kids full time until staff is vaccinated and/or the six-foot distance is no longer needed,” she said.

She said the district’s middle and high school simply doesn’t have space to accommodate that distance requirement if all students return. “I don’t see how I can have more than half the population in at a time keeping the six-foot distance.”

And in Portland, Ore., the teachers union sees the guidelines as helping their case for caution in returning to buildings.

“The new CDC guidelines are very much in line with what we’ve been asking for since August, and it’s helpful, with so many varying sources of information and recommendations, to have something from the federal government that is clear,” said Elizabeth Thiel, president of the Portland Association of Teachers.

It’s frustrating for Joseph G. Allen of the Harvard T.H. Chan School of Public Health. He thinks the CDC should not have tied reopening to community spread but should have put more emphasis on ventilation. Overall, he sees a missed opportunity to help schools to reopen safely.

“It was a chance to clear up a lot of confusion and I think it had the opposite effect,” he said. “If you follow the letter of the law for this document, it’s essentially saying schools will not be open full time this year.”