Imagine, for a moment, American children returning to school this fall.

The school week looks vastly different, with most students attending school two or three days a week and doing the rest of their learning at home. At school, desks are spaced apart to discourage touching. Some classrooms extend into unused gymnasiums, libraries or art rooms – left vacant while schools put on hold activities that cram lots of children together.

Arrival, dismissal and recess happen on staggered schedules and through specific doors to promote physical distancing. Students eat lunch at their desks. Those old enough to switch classes move with the same cohort every day – or teachers move around while students stay put – to discourage mingling with new groups.

Teachers and other education staff at higher risk of contracting the virus continue to teach from home, while younger or healthier educators teach in-person.

Everyone washes their hands. A lot.

Frequently touched school surfaces get wiped down. A lot.

That outline of a potential school day was drawn from interviews with more than 20 education leaders determining what reopened schools might look like come fall. In the absence of a vaccine for COVID-19, they know social distancing and hygiene will be important to limit spreading the virus. The question is how to implement those measures in schools usually filled with crowded hallways, class sizes of more than 30 people and lunchrooms of hundreds.

"The whole thing is overwhelming," said Dan Weisberg, a former district official and the head of TNTP, a nonprofit formerly known as The New Teacher Project that helps districts recruit and hire more effective teachers.

Beyond blanket health recommendations, schools will have to figure out the rest by themselves – with little new money to pay for the changes they need to make.

"This is where federal dollars could help," Weisberg said. "This is where state guidance could help. This is where galvanizing people behind the idea on how to plan for next year could help."

Instead, schools are getting conflicting cues. President Donald Trump reportedly said in a call with governors Monday that they should "seriously consider" reopening public schools before the end of the academic term. That's after 43 states and Washington, D.C., have already ordered or recommended schools be closed through the end of the school year, according to Education Week magazine.

When will schools reopen?Not soon, education leaders say, despite Trump's declarations

A draft of new guidance from the Centers for Disease Control and Prevention on reopening the economy recommends that schools place desks six feet apart, serve lunch in classrooms and close playgrounds, according to The Associated Press.

The CDC's guidance for schools so far has been vague. It suggested schools look to their local health officials to make decisions on dismissals, event cancellations and other social distancing measures. The CDC never suggested outright that schools should cancel – governors and school leaders called for that on their own.

'Economics will drive choices' made by school districts

Reopening schools is critical to fully bring back the economy. More parents can work when their children are in school. Just as important: Many kids aren't learning much at home. Those learning the least are students who lack devices and internet access – many of whom were already academically behind before schools closed.

U.S. schools were not prepared for an overnight shift to virtual learning, and the situation has exacerbated the inequities between students who have support and resources at home and those who don't.

'Historic academic regression':Why homeschooling is so hard amid school closures

But bringing kids back to school presents major worries about health, not so much for children – who seem to be less at risk for getting sick – but fortheir teachers and parents. Preliminary research has shown that children can carry and transmit the virus without showing symptoms themselves.

Many school buildings lack the space to keep children a recommended six feet apart. That's why education leaders foresee a need to continue virtual learning, with kids attending school in person on alternating days or weeks.

And that's only the start. Districts also must figure out food service, especially for the 52% of students who qualify for free- or reduced-price lunches and depend on those meals. Schools must provide enough qualified staff to teach students in smaller groups. They must provide emotional support to staff and students. And they need to develop measures to help catch up children who have fallen the farthest behind.

"There is going to be attrition of teachers," said Weisberg. "And whatever challenges exist are going to be way worse if you’re not fully staffed."

Then schools have to figure out how to pay for it all.

"Economics will drive the choices districts make," said Marguerite Roza, a professor and director of the Edunomics Lab at Georgetown University.

On Monday, superintendents from 62 of the country's largest school districts called on Congress to provide about $200 billion more in educational stabilization funds to help prop up budgets, buy more technology for families and better serve low-income students and those with special needs.

In California's Long Beach Unified School District, with 84 schools and 10,000 employees, departments are reducing their budgets in anticipation of receiving less money from the state. Superintendent Chris Steinhauser, who signed the letter to Congress, said his district expects to receive around $10 million to $15 million in federal stimulus dollars from the CARES Act, but that's about one-quarter of the federal aid the district got in the first year of the last economic recession.

"I would argue the economic meltdown of today is going to be far worse," Steinhauser said.

How other countries are reopening schools

U.S. leaders are watching and learning from other countries that are reopening their schools. Denmark reopened schools on April 15 for lower grades. Classrooms held no more than 10 students each, and desks were placed more than six feet apart. In some cases, children move in cohorts that remain the same day to day.

Leaders in Israel this week tentatively approved sending students up to third grade back to school starting Sunday, according to The Times of Israel. Older students will continue learning from home. Classes will be kept small, and kindergartners will be split into groups that meet on different days, according to the plan, which is contingent on infection rates staying low.

Sweden's strategy:Top official says 'herd immunity' might be a few weeks away

Shanghai and Beijing started bringing some students back this week. Germany has brought middle and high school students back to complete advancement exams.

Estonia plans to start bringing back children with disabilities in mid-May, according to Jake Bryant, a former teacher and associate partner at the global consultancy firm McKinsey & Company, which released a new report Wednesday with ideas for schools to consider as they plan to reopen.

U.S. schools could consider bringing back vulnerable students first for more one-on-one help, or scheduling more days of in-person instruction for them, Bryant said. Students with disabilities, or those whose families rely on schools for food or other assistance, could attend in-person three days a week, while more highly resourced students with access to technology at home could attend two days a week.

"I don't believe reopening will be a linear path to normalcy," Bryant said.

He also said schools will have to get better at remote learning, whether because of a virus resurgence, a need to quarantine infected students or because school days need to be split up to create more space in classrooms.

"Students will face a steep hill to return to grade level, as they likely have less learning time until a vaccine is widely available," he added.

Some lessons can be learned from schools in West Africa that reopened in 2015 after months of closures to contain the Ebola virus outbreak.

Deborah Malac, a U.S. ambassador to Liberia at the time, said cities and counties will probably have to adopt a patchwork of solutions, based on their rates of local infections. She said the lack of data about infections and other aspects of COVID-19 is still the greatest challenge facing U.S. health officials.

“We went through all of this (in Liberia) for months," she said. "Once the epidemic is in front of you and you’re trying to catch up, it’s not a pleasant place to be in."

Beyond academics, schools are burdened by meal distribution

Schools have become a key resource for families needing food assistance, which will likely continue no matter what schooling scenario takes shape.

Breakfast and lunch in buildings this fall will largely depend on how districts weather food and money shortages now plaguing emergency feeding programs that have provided meals to students ever since schools closed.

Food service workers have had to rethink traditional breakfast because of shortages of staples like milk, according to Diane Pratt-Heavner, spokeswoman for the nonprofit School Nutrition Association.

“Most of our school nutrition directors have been working through their (non-perishable) inventory to make sure nothing is wasted, but that means that when they get back to school they won’t have any reserves,” she said. “So they’ll have to find a way to replenish in order to give students a proper meal.”

Katie Wilson, CEO of the Urban School Food Alliance, says the 12 large school districts in her association are collectively losing $38.9 million a week by serving food to their students during school closures without the revenue they generate from students who pay for meals.

Without a federal bailout, school food programs will be forced to make cuts, meaning there may be fewer cafeteria workers to prepare meals, Wilson said. Schools will also have to figure out how to prepare and serve foods in buildings while adhering to social distancing measures.

School food workers are already running low on supplies, gloves, masks and cleaning supplies, Pratt-Heavner and Wilson said.

Daphne Duret with the USA TODAY Network contributed to this report.

Education coverage at USA TODAY is made possible in part by a grant from the Bill & Melinda Gates Foundation. The Gates Foundation does not provide editorial input.