Coronavirus has upended lives and workplaces around the world, with more than a third of the globe under lockdown. At the United Nations headquarters in New York, where about 10,000 people usually work, a skeleton staff of a few hundred is on site, ensuring the world body's vital operations continue - such as peacekeeping and humanitarian operations. As the COVID-19 pandemic spreads fast, the UN is critically concerned about those most vulnerable - especially refugees and people trapped in conflict situations. The UN has launched a $2bn global humanitarian appeal to assist fragile states and those most vulnerable. It says prevention and suppression of the virus must be a priority for leaders of all countries. Leading UN officials have also called for all conflicts to cease and warring parties to focus their efforts on tackling the coronavirus. To discuss the global efforts against COVID-19 and the risks facing the world's most vulnerable populations, Talk to Al Jazeera speaks to Antonio Guterres, the UN secretary-general; Mark Lowcock, the under-secretary-general for Humanitarian Affairs; and Filippo Grandi, the UN High Commissioner for Refugees. - Subscribe to our channel: http://aje.io/AJSubscribe - Follow us on Twitter: https://twitter.com/AJEnglish - Find us on Facebook: https://www.facebook.com/aljazeera - Check our website: https://www.aljazeera.com/