Education of over 154 crore students has been disrupted after their schools were shut down due to the cornovirus epidemic, according to the UN education agency Unesco.
UNESCO said girls will be the worst hit as it will lead to increased drop-out rates and further entrench gender gaps in education.
The global scale and speed of the current educational disruption is unparalleled and disadvantaged children are the worst-hit by the emergency measures, said Unesco Director-General Audrey Azoulay.
"While temporary school closures as a result of health and other crises are not new, unfortunately, the global scale and speed of the current educational disruption is unparalleled and, if prolonged, could threaten the right to education, she said.
According to Giannini, for girls living in refugee camps or who are internally displaced, shutting down of schools will be the most devastating as they are already at a disadvantage and education responses must prioritise the needs of adolescent girls' at the risk of reversing 20 years of gains made for girls' education.
"Refugee girls at secondary level are only half as likely to enrol as their male peers. 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 in countries 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. While many girls will continue with their education once the school gates reopen, others will never return to school," she said.
The United Nations Educational, Scientific and Cultural Organization (Unesco) has called for policy-makers and practitioners to look into lessons from the past crises to address the challenges faced by girls as the governments of various counties prepare for "indefinite" school closures.
"As governments prepare for indefinite school closures, policy-makers and practitioners can look to lessons from the past crises to address the specific challenges faced by girls. We, therefore, call on governments to protect progress made in favour of girls' education through six gender-responsive, evidence-based and context-specific actions," Giannini said.
The six-point strategy suggested by UNESCO for the purpose includes leveraging teachers and communities, adopting appropriate distance learning practices, considering the digital divide, safeguarding vital services and engaging young people.