The spike in Covid-19 cases in the United States, driven largely by the Delta variant, is on a collision course with back-to-school season, which will see children—who are more affected by the variant—returning to in-person instruction en masse, often without masks, vaccinations, regular testing, or better ventilation.

Experts are worried that the results will be disastrous. And they fear that the worst of the crisis will hit the communities that have already been devastated by the pandemic, and have the fewest resources to make schools safer for children.

“I’m not optimistic at all,” said Dr. Amy Falk, a pediatrician in rural Wisconsin. “I’m just really worried about the school year.”

Falk cowrote one of the major reports on what schools can do to educate kids safely during the pandemic. Last year, the schools that required masks, as well as other measures like testing, cohorting, and upgrading ventilation, did not see significant spread, as multiple reports have shown. The US Centers for Disease Control and Prevention (CDC) has based its back-to-school advice on this science.

But Falk is worried that what worked a few months ago won’t stop Delta as easily now.

“We’re dealing with essentially a completely different virus than we were last school year,” Falk said. “It is just frightfully more infectious.” Schools that might have gotten by with limited measures last year, she said, could be hit very hard now.

At the same time, many districts are discarding all or most of these precautions entirely. Many children are returning to schools where masks will be optional or even prohibited, and they’re often coming back to buildings with inadequate ventilation or room for physical distancing. Some schools are not even testing or quarantining those who come into contact with the virus. And the children in many of the communities discarding these measures are already at high risk of getting very sick.

“Last year, schools did not seem to drive community spread. I think we will see differences this year,” Falk said. With the more transmissible Delta variant and fewer precautions, schools could become a hot spot for spread among communities, she said. “Delta is an entirely different game. Going at it with less mitigation starting school is going to be a big mistake.”

In the last week of July 2021, kids accounted for nearly one-fifth of all new Covid-19 cases in the country, almost doubling in the course of a single week and representing the biggest surge among children in the entire pandemic. There has been an almost-vertical increase in hospitalizations among children, with children’s hospitals filling up and pediatricians increasingly concerned about the more transmissible Delta variant.

“This may be the most dangerous time during the pandemic so far for our children,” said Dr. Diego Hijano, a pediatric infectious disease doctor at St. Jude Children’s Research Hospital, calling the rise in cases among children an “ominous warning sign that couldn’t come at a worse time as children are heading back to school.”

The CDC and the American Academy of Pediatrics have recommended masks for everyone in schools, including those who have been vaccinated. National and local teachers unions have also put their weight behind masking, testing, and vaccinating all eligible students and staff.

In the face of a markedly more contagious variant, protective measures are crucial for slowing the spread of the virus, experts say. “It’s important to put several measures in place because no one is 100 percent effective,” Hijano said. “And while vaccination is the best tool we have, we understand that it’s not reaching everyone in the same way”—making other preventative measures important.

“It just makes it more urgent that districts mount those strategies now,” said Paul Reville, a professor at the Harvard Graduate School of Education and the founding director of the Education Redesign Lab.

Infectious disease modelers this summer predicted a sharp uptick in cases if masking and other precautions aren’t taken—and the lead researcher has said he may have been “too optimistic” about how high cases could rise. Another model found that 90 percent of students could get sick by the end of the year—but 80 percent of those cases would be prevented by masks and testing.

About 12 million kids between the ages of 12 and 18 have received at least one dose of a Covid vaccine. There are about 25 million kids in that age group in the United States, so less than half of eligible students have started vaccination. For those 11 and younger, vaccines are expected in the next few months, but there’s a lot of transmission that can happen before then.

In June 2020, about half of the school districts in the country needed to update or replace heating, ventilation, and air conditioning or plumbing systems, according to a report from the US Government Accountability Office.

Massive relief programs from the federal government include funding to upgrade crucial systems in order to prevent the spread of the virus within schools. But “this money is just rolling out now,” Reville said, so “they haven’t been able to make the investments yet or the work hasn’t been able to be done.”

For schools in places like California, improving ventilation can be as easy as opening a window, provided the windows aren’t sealed shut.

But in places like Wisconsin, that’s not really an option. “The ventilation systems are antiquated and can be complex,” Falk said. Some schools are using the federal funding to replace air filters, but it can be expensive or impossible to completely overhaul the entire system. “A lot of schools are really stuck with whatever types of building limitations that they end up having,” Falk said. This is particularly true in poorly funded districts where the students also tend to be at greater risk for getting and dying from the virus.

Some schools don’t even have ventilation systems to upgrade. In Philadelphia earlier this year, a school’s strategy involving box fans sparked outrage from the community, which has long been concerned about dangers like lead paint and asbestos. The US school system was already plagued by deep inequalities long before the pandemic threw them into sharp relief.

“Some of the inequities have accumulated over decades,” Reville said. “The deterioration of facilities can’t be totally mended by one, however generous, influx of federal funding right now.” Some families in vulnerable school districts decided to homeschool in the past year and a half, and Reville expects such decisions to continue this year. “A lot of parents aren’t going to feel safe if this trend continues.”

About one-quarter of Black parents and Hispanic parents said they were not sure about sending their children back to school, according to a survey from June—before the Delta variant began circulating. They also strongly supported mask and testing requirements.

“Schools are going to need to put in place significant preventative and protective procedures—and many of those are controversial, sadly,” Reville said. While many educators know what works to help stop the spread of the virus, they are frequently hemmed in by limited resources and even by political decrees.

Vaccination and masking can be relatively simple and effective protection measures when completely overhauling school buildings isn’t feasible, Hijano said. Mask mandates can be “controversial for parents because some parents do not like it. But, as I say, it’s not controversial for scientists.”

One school in Mississippi had to quarantine 40 percent of students in its first week, and the district is now going fully virtual. Another district in South Carolina is also pivoting fully to virtual after a record number of students became ill in the first nine days of school.

While it’s not yet clear if the Delta variant makes us sicker, the more cases there are, the more children will become very sick and die. It’s simple math, Hijano said. “The more cases we see, the more we’re going to have severe disease.” And, he said, hospitalization and death are not the only outcomes to worry about. Kids also experience the lingering symptoms of long Covid, even after mild cases, including brain fog, exhaustion, and cognitive issues.

“Most of them aren’t getting serious cases” of Covid-19, Reville said. “But at the same time, there are long-haul effects.” There’s also the risk of kids bringing the virus home to their families and causing more community spread.

The sharp rise in cases is also putting severe strain on the very people who help kids—including those who work in hospitals and schools.

“Hospitals are full,” Hijano said. “Most of the health care providers are suffering…. It’s nonstop work, day in and day out.”

“School leaders who are already exhausted from the rigors of the past year and a half are going to have to bend over backwards, are going to have to be as nimble as possible, in responding to these situations,” Reville said. “They keep changing almost overnight, and it’s very difficult for people in the field to keep up with those changes.”

But, he added, these changes offer schools long-needed opportunities to improve. Already, schools are receiving more funds to offer mental health support to those who have suffered disproportionately in the past few months—support that could help students moving forward. Programs like the child tax credit, which could cut child poverty in half, could make a massive difference in how well students are able to focus and perform in school.

“What the pandemic has laid bare is the degree and breadth of services, supports, and opportunities that young people need, in addition to whatever happens at school,” Reville said. This kind of support—providing food, health care, a place to stay—are prerequisites for being able to learn.

“We’re seeing, I hope, the beginning of a new era, where we begin to start looking at what it takes to create equity in this country,” he said. “What it takes to ensure children’s success.”