Not counting schools which are closed due to holidays, more than 600 million children are currently missing classes, UNICEF spokesman James Elder said on Tuesday.

About 40 per cent of school-age children in eastern and southern Africa are not in school, he said.

While 37 million had already not been attending classes before the pandemic, an additional 32 million children were now also missing out because schools are closed or because they did not return to class after schools reopened.

Few schools in the region were able to offer remote learning, Elder said.

"Education, safety, friends and food have been replaced by anxiety, violence and teenage pregnancy," Elder said, adding that the number of pregnancies among 10- to 24-year-olds increased by more than 20 per cent in the past year in Uganda alone.

UNICEF predicts that the consequences of this situation will be felt for decades, citing a World Bank report that estimates this generation of students will earn a total of $US10 trillion ($A14 trillion) less during their lifetime than they would with a complete education.

Each year of schooling raises the earning potential by 10 per cent, according to UNICEF.

In light of the lack of coronavirus vaccine supplies in poorer countries, reopening schools should not be tied to the vaccination of all teachers and students, Elder said.

He called on governments and donor countries to invest more to get children and teenagers back into school and for pregnant women and young mothers to be allowed to continue to attend classes.

Australian Associated Press