The closing of schools around the world is sure to hurt most students in some way, but it is girls from marginalized countries whose education will be affected the most, experts say.

With some 1.5 billion students affected by school closures around the world, according to a U.N. agency, more than 111 million of them are girls who live in the world’s least developed countries, where education is already a struggle for them because of family and societal pressures.

And it is they who are more at risk than boys of never returning to school, according to officials at the United Nations Educational, Scientific and Cultural Organization, or UNESCO.

“We are only beginning to understand the economic impacts of covid-19, but they are expected to be widespread and devastating, particularly for women and girls,” Stefania Giannini, UNESCO’s assistant director general for education, and Anne-Birgitte Albrectsen, chief executive for Plan International, a development and humanitarian organization, wrote in a paper.

“In the Global South, where limited social protection measures are in place, economic hardships caused by the crisis will have spill-over effects as families consider the financial and opportunity costs of educating their daughters,” they wrote. “While many girls will continue with their education once the school gates reopen, others will never return to school.”

A new report by the nonprofit international organization called the Malala Fund analyzed data from the 2014-2015 Ebola epidemic in several African countries and concluded that as many as 10 million secondary school-age girls who were in school before the coronavirus pandemic began this year will not return.

The fund was founded by Malala Yousafzai, the youngest Nobel Peace Prize recipient in history for her advocate of girls’ education, along with her father, Ziauddin Yousafzai.

“We find that marginalised girls are more at risk than boys of dropping out of school altogether following school closures and that women and girls are more vulnerable to the worst effects of the current pandemic,” said the report, titled “Girls’ Education and covid-19″ (which you can see here or below).

As an example, at the height of the Ebola epidemic, more than 10,000 schools, affecting nearly 5 million children, were closed in the African countries of Guinea, Liberia and Sierra Leone. When schools reopened more than six months later, in 2015, students had lost an approximate 1,848 hours of education, ranging from 33 weeks in Guinea to 39 weeks in Sierra Leone, the fund said.

“Prior to the outbreak in Sierra Leone, girls’ education already lagged behind that of boys, with girls acquiring just 1.8 years of schooling on average in comparison to the four-year average for boys,” the report said. "Likewise, girls in Guinea completed only 0.9 years of schooling as compared to the 2.7-year average for boys.

“This gendered difference in educational attainment is a recurring theme in countries where girls face the greatest challenges,” it said."Consequently, the simple loss of even six months of education as a result of COVID-19 will have a proportionally greater impact on girls in low- and lower-middle-income countries; in some countries, they could lose 50% of their total years of education."

Both Giannini and Albrectsen, as well as the Malala Fund report, said that after schools reopened many girls became the chief source of income for their families and could not attend school if they had re-enrolled.

Giannini and Albrectsen wrote that during Africa’s Ebola crisis, girls not only saw their education interrupted but also, some studies found, “that the closure of schools increased girls vulnerability to physical and sexual abuse both by their peers and by older men, as girls were often are at home alone and unsupervised.”

“Transactional sex was also widely reported as vulnerable girls and their families struggled to cover basic needs,” they said. “As family breadwinners perished from Ebola and livelihoods were destroyed, many families chose to marry their daughters off, falsely hoping this would offer them protection.”

Girls living in refugee camps will be hardest hit, with refugee girls at secondary school-age only half as likely to enroll in schools as their peers, they wrote.

Here’s the report from the Malala Fund: