BOSTON (AP) — As the harmful effects of extended pandemic school closures become more apparent, some educators and parents have regrets.

They’re questioning decisions in cities across the U.S. to remain online long after clear evidence emerged that schools weren’t COVID-19 super-spreaders — and months after life-saving adult vaccines became widely available.

In Chicago, Marla Williams initially supported the school system’s decision to instruct students online during the fall of 2020. Williams, a single mother, has asthma, as do her two children. While she was working, she enlisted her father, a retired teacher, to supervise her children’s studies. It didn’t work.

Her son lost motivation and wouldn’t do his assignments. Once he went back on a hybrid schedule in spring 2021, he started doing well again.

“I wish we’d been in person earlier,” Williams said. “Other schools seemed to be doing it successfully.”

There are fears for the futures of students who don’t catch up. They run the risk of never learning to read, long a precursor for dropping out of school. They might never master simple algebra, putting science and tech fields out of reach. The pandemic decline in college attendance could continue to accelerate, crippling the U.S. economy.

In a sign of how inflammatory the debate has become, there’s sharp disagreement even about how to label the problems created by online school. “Learning loss” has become a lightning rod. Some fear it might brand struggling students or cast blame on teachers, and they say it overlooks the need to save lives during a pandemic.

Regardless of what it’s called, the casualties of Zoom school are real.

The scale of the problem and the challenges in addressing it were apparent in Associated Press interviews with nearly 50 school leaders, teachers, parents and health officials, who struggled to agree on a way forward.

Some warned against second-guessing the school closures for a virus that killed over a million people in the U.S. More than 200,000 children lost at least one parent.

“It is very easy with hindsight to say, ‘Oh, learning loss, we should have opened.’ People forget how many people died,” said Austin Beutner, former superintendent in Los Angeles, where students were online from March 2020 until the start of hybrid instruction in April 2021.

The question isn’t merely academic. It’s conceivable another pandemic might emerge — or a different crisis.

But there’s another reason for asking what lessons have been learned: the kids who have fallen behind. Some third graders struggle to sound out words. Some ninth graders have given up on school because they feel so behind they can’t catch up. The future of American children hangs in the balance.

When COVID-19 first reached the U.S., scientists didn’t fully understand how it spread or whether it was harmful to children. American schools, like most around the world, understandably shuttered in March 2020.

That summer, scientists learned kids didn’t face the same risks as adults, but experts couldn’t decide how to operate schools safely.

The risk assessment varied depending on how vulnerable a community felt to the virus. Politics was a factor, too. Districts that reopened in person tended to be in areas that voted for President Donald Trump or had largely white populations.

By winter, studies showed schools weren’t contributing to increased COVID-19 spread in the community. Classes with masked students and distancing could be conducted safely, growing evidence said. Once the vaccine was available, some Democratic-leaning districts started to reopen.

Yet many schools stayed closed well into the spring, including in California, where the state’s powerful teachers’ unions fought returning to classrooms, citing a lack of safety protocols.

Nationally, kids whose schools met mostly online in the 2020-2021 school year performed 13 percentage points lower in math and 8 percentage points lower in reading compared with schools meeting mostly in person, according to a 2022 study by Brown University economist Emily Oster.

The setbacks have some grappling with regret.

“I can’t imagine a situation where we would close schools again, unless there’s a virus attacking kids,” said Eric Conti, superintendent for Burlington, Massachusetts.

Still, many school officials said with hindsight they’d make the same decision to keep schools online well into 2021. Only two superintendents said they’d likely make a different decision if there were another pandemic that was not particularly dangerous to children.

In some communities, demographics and the historic underinvestment in schools loomed largely. In the South, Black Americans’ fear of the virus was sometimes coupled with mistrust of schools rooted in segregation. Cities from Atlanta to Nashville to Jackson, Mississippi, shuttered schools — in some cases, for nearly all of the 2020-2021 school year.

In Clayton County, Georgia, home to the state’s highest percentage of Black residents, schools chief Morcease Beasley said he knew closing schools would have a devastating impact, but the fear in his community was overwhelming.

“I knew teachers couldn’t teach if they were that scared, and students couldn’t learn,” he said.

Among teachers, there’s some dispute about online learning’s impact on children. But many fear some students will be scarred for years.

“Should we have reopened earlier? Absolutely,” said California teacher Sarah Curry. She initially favored school closings in her rural Central Valley district but grew frustrated with the duration of distance learning.

But the nation’s 3 million public school teachers are far from a monolith.

Jessica Cross, who taught ninth-grade math on Chicago’s west side at Phoenix Military Academy, feels her school reopened too soon.

“I didn’t feel entirely safe,” she said. Mask rules were good in theory, but not all students wore them properly. She said safety should come before academics.

A representative from the American Federation of Teachers declined in an interview to address whether the union regrets the positions teachers took against reopening schools.

“If we start to play the blame game,” said Fedrick Ingram, AFT’s secretary-treasurer, “we get into the political fray of trying to determine if teachers did a good job or not. And I don’t think that’s fair.”

Regrets or no, experts agree: America’s kids need more from adults if they’re going to be made whole.

The country needs “ideally, a reinvention of public education as we know it,” Los Angeles Superintendent Alberto Carvalho said. Students need more days in school and smaller classes.

Short of extending the school year, experts say intensive tutoring is the most efficient way to help students catch up. Saturday school or doubling up on math or reading during a regular school day would also help.

Too few school districts have made those investments, Harvard economist Tom Kane said. Summer school is insufficient, Kane says – it’s voluntary, and many parents don’t sign up.