All schools around the world must remain open despite the continued spread of COVID-19, in particular its "omicron" strain, the United Nations Children's Fund (UNICEF) said.

UNICEF Executive Director Henrietta Faure said in a statement titled "No Excuses. Schools must stay open. Children can't wait," she warned of the irreversible consequences of the education crisis.

"The COVID-19 Omicron option continues to march around the world, and in this situation we call on governments to do everything in their power to prevent further disruptions in children's education," Henrietta Fore said.

She stressed that in order to solve the crisis in education, it is necessary to return children to full-time education. This requires keeping schools open, providing urgent vaccinations for teachers and school staff, and, if possible, vaccinating schoolchildren, but not making vaccination a prerequisite for their return to school.

"In line with recommendations from the World Health Organization, UNICEF calls for keeping schools open and ensuring that countries' strategies to combat COVID-19 promote the participation of all children and adolescents, including unvaccinated children, in education and other areas of public life," the statement said.