Closing of schools across the world should be the last resort in the fight against the fast-spreading Omicron Covid-19 variant, outgoing Unicef Executive Director Henrietta Fore said.
"Nationwide school closures should be avoided whenever possible," Xinhua news agency quoted Fore as saying in a statement on Friday.
"When Covid-19 community transmission increases and stringent public health measures become a necessity, schools must be the last places to close and the first to re-open.
"Another wave of widespread school closures would be disastrous for children... The evidence is clear: Prolonged, nationwide school closures; limited resources for students, teachers and parents; and lack of access to remote learning have wiped out decades of progress in education and rendered childhood unrecognizable," the Unicef head added.
She said that beyond lost learning, children also lost school safety, daily in-person interactions with friends, access to healthcare and often their only nutritious meal of the day, adding that this generation of schoolchildren could collectively lose $17 trillion in potential lifetime earnings.
"We know that mitigation measures in schools are effective," she said.
"We must use this knowledge to do everything we can to keep schools open. We must also increase investments in digital connectivity to make sure that no child is left behind."
Fore, who will be relieved of the post as Unicef chief, said that next year could not be another year of disrupted learning.
"It needs to be the year that education, and the best interests of children, take precedence."
Fore announced in July her intention to resign as Unicef Executive Director because of family health issues.
Catherine Russell, a senior White House official, has been appointed to succeed Fore by UN Secretary-General Antonio Guterres.
Fore said she would remain in her post until a successor could take over.
Russell said she would start as Executive Director early next year.