9 out of 10 children are out of school worldwide. What now?

Right now students are out of school in 185 countries. According to UNESCO, that's roughly 9 out of 10 schoolchildren worldwide.

The world has never seen a school shutdown on this scale. And not since Great Britain during World War II has such a long-term, widespread emptying of classrooms come to a rich country.

To get a little perspective on what this all might mean, I spoke with several experts in the field known as "education in emergencies." Some have been part of the response to national, longterm school interruptions caused by war, refugee crises, natural disasters and epidemics like Ebola. Others have studied the breakdown and recovery process. Again, there is no situation that is precisely similar to what schools around the world are going through now, but here are some lessons these experts have learned from other education emergencies.

From New Orleans and Rwanda: It can take years for students to recover the learning they've lost

Hurricane Katrina closed most public schools in New Orleans for the entire fall term of 2005. Most of those students enrolled in other schools elsewhere, from Baton Rouge to Houston and beyond. In many cases, the schools they enrolled in were of higher quality than the schools they had left — because the schools in New Orleans were extremely low-performing before the storm.

So, you might think that the learning interruption wouldn't be that bad. You'd be wrong.

Doug Harris at Tulane University was part of a research team tracking students as they returned to New Orleans and reenrolled in newly reorganized schools. He says it took two full school years — from the spring of 2006 to the spring of 2008 — for those returning students to fully recover their lost learning. There's "suggestive evidence," he says, that the negative impact was worse for low-income and African American students.

Harris says that what hurt these kids' learning wasn't just the interruption in class time. The economic impact and emotional trauma were probably just as important. So was the dislocation itself: the experience of enrolling in new and unfamiliar schools where Katrina "refugee" students were not always welcomed.

All of these factors — social dislocation, economic uncertainty — apply in spades to the coronavirus situation, says Harris. So, he says, we should expect something similar in terms of recovery time. "The social and economic situation always bleeds into the school," he says.

One paper that compared various communities that were affected, to different degrees, by the Rwandan genocide in 1994 found that affected children caught up in educational attainment by 2010 — 16 years later.

Afghanistan, Syria, Afghanistan, Somalia, Philippines, Sri Lanka: Continuity efforts won't reach everyone, but they are still necessary

Amid the coronavirus shutdown, many children in the United States can't access distance learning because they lack computers and internet access, and some are struggling to participate because they have a learning disability. Nevertheless, the federal government so far has guided school districts to keep trying to push ahead with interim efforts to keep students learning anyway, while doing their best to reach as many students as they can.

"The choice to do nothing, because it can't reach all immediately, ends up just exacerbating existing inequalities," says Sarah Dryden-Peterson, a researcher at the Harvard Graduate School of Education with experience in sub-Saharan Africa.

She adds that, whether any assistance is offered during school closures or not, families with the means will work hard to help their children access education anyway. She says this was the case recently during Hong Kong's school closures, where families who could afford to sent their children abroad to school.

Dryden-Peterson's view tracks with what the international aid community considers to be best practice, agrees Rebecca Winthrop, co-director of the Center for Universal Education at the Brookings Institution. "Don't stop helping people just because you can't help everyone, but definitely have a pro-equity lens."

Syria, Venezuela, Myanmar, West Africa: Children are at risk for toxic stress — but continuity efforts can help

Even the most fortunate of U.S. children are going through a version of what's called an "adverse childhood experience" right now. That's the term researchers use for a traumatic event in a child's life, such as physical or verbal abuse, a divorce, or the death, incarceration or substance abuse of a parent. The effect of these experiences is cumulative — experiencing four or more of them is considered a major risk factor for long term physical health problems, including conditions like cancer and heart disease.

Sarah Smith is the senior director of education at the International Rescue Committee. She says that when social disruption interrupts education, we should expect effects on brain development, especially for students who already had a risk factor or two in their biology or their family life.

"Their social and emotional well-being is at risk," she says. "And they're more likely to experience, for instance, toxic stress, which is just a disruption in their brain development." This, Smith adds, can have not only short-term consequences for emotional and physical health, "but also long-term consequences for their overall well-being, their ability to hold down a job, their ability to learn in school later if they get back into school, and their fiscal health."

However, Rebecca Winthrop notes that efforts that keep teachers in touch with students can help reduce these effects. "If provided in a way that ... continues learning in some form, they can be a real protective factor against anxiety and depression for kids."

New Orleans, Syria: Expect high school graduation and college-going rates to take a hit

Doug Harris at Tulane says that, based on what he saw in New Orleans after Katrina, he expects the current shutdown to drive down high school graduation rates and college enrollments. Harris notes that college enrollments in New Orleans have yet to return to pre-Katrina levels, particularly at institutions that primarily serve low-income students, such as the University of New Orleans.

There are economic factors for teenagers. "Their parents just lost their jobs and they've got younger siblings to take care of while their parents are out trying to find work and trying to manage things," he explains. "So I think, unfortunately, we're going to see a spike in the high school dropout rate."

Sarah Smith at IRC looks at the developmental reasons teenagers are particularly at risk for leaving school. "Adolescence [is] a period of rapid change and rapid development," she says. "So if they're experiencing adversity while they're going through adolescence and another period of change, it can be very detrimental."

Younger children, Smith adds, can be more resilient to a disruption like this, as long as they are with their immediate family, who are ideally the most important sources of support in their lives. But when it comes to teenagers, the important people are "more likely to be peers and mentors. If those ties to those people are disrupted, that can really affect their overall well-being."

Puerto Rico, New Orleans, Rwanda: School systems are sometimes entirely remade

Sometimes, the major disruption that closes schools becomes an opening for dramatic changes to the structure of the school system. New Orleans became an all-charter district. Puerto Rico, after the devastation of Hurricane Maria in 2017, passed a law reorganizing the school system and creating charters and voucher programs. And education reforms in Rwanda emphasized broader access, student-centered teaching techniques, and a shift in the language of instruction from French to English.

Harris' research, along with others, has showed generally positive effects for reforms in New Orleans, although they were not without tradeoffs. Students who returned to New Orleans in 2006 had caught up academically by 2008, and they continued to make gains for the next five years in test scores and educational attainment. That progress, Harris says, has since leveled off. Rwanda has also been generally recognized for prioritizing educational progress and access in the recovery from the genocide.

In Puerto Rico, by contrast, the picture is far from rosy. The indictment of the education secretary on corruption charges earlier this year was a bad sign for educational progress. Patricia Virella, at Sarah Lawrence College, a scholar who is originally from Puerto Rico, says that, in her opinion, the closure of many public schools created a loss that was cultural, not just educational: "the pride of learning, the culture of Puerto Rico, and being taught by teachers who understand our culture."

In the United States, Education Secretary Betsy DeVos has long been a champion of alternatives to public schools, including homeschooling, vouchers and charter schools. In the wake of coronavirus-related school closures, she's proposed "microgrants" that would go directly to families to supplement children's education. If enacted, this would essentially constitute a federal homeschool voucher program, a big change in federal policy.

Liberia, Sierra Leone, Syria, Jordan, Iraq, Lebanon, Myanmar, Somalia, China: Media can be part of the solution

"During the Ebola crisis in West Africa in 2014, radio was used as a way to be able to reach all children with school-based lessons," says Harvard's Sarah Dryden-Peterson.

She's seen similar efforts in recent months, for example, "where primary school students in China have been learning via television broadcast."

In refugee contexts, currently with the Rohingya in Myanmar and with Syrian refugees in Lebanon and Turkey, Sarah Smith of the IRC says her organization is working with Sesame Workshop to produce media content to help support early education and social and emotional learning.

Dryden-Peterson also says that while mass media is standardized and widely accessible, it should also be balanced with more individualized, lower-bandwidth, efforts.

"We see Somali refugee teachers, for example, using social media to provide feedback on assignments to students, even when they're living at great distances from each other. Simple text messages or short videos that can be accessed without broadband."

None of these efforts can necessarily keep students progressing at the same rate academically as they would if school were in session. The intention, says Dryden-Peterson, is instead "to build a shared sense of stability and belonging." In other words, to keep kids feeling connected to the school community and to their education.

All of these experts told NPR that when students return to their classrooms — in the U.S. and around the world — it will be in a new world. They will need lessons and school structures that help them cope with the new realities, that give them hope and the skills they need to be part of solutions. This might mean assessing student's new starting points, summer school, remediation or acceleration. It might mean studying public health and epidemiology. It will certainly mean social and emotional supports that help children, teachers, and families recover from this unprecedented break.

Copyright 2020 NPR. To see more, visit https://www.npr.org.