World Health Organisation chief Tedros Adhanom Ghebreyesus said a Covid variant-driven ‘Tsunami’ threatens to overwhelm healthcare systems. WHO chief said the Delta and Omicron variants of concern were ‘twin threats’. "I am highly concerned that Omicron, being more transmissible, circulating at the same time as Delta, is leading to a tsunami of cases," he said at a press briefing. "This is and will continue to put immense pressure on exhausted health workers, and health systems on the brink of collapse," he added. According to WHO's figures, the number of COVID-19 cases recorded worldwide increased by 11 per cent last week compared with the previous week, with nearly 4.99 million newly reported from Dec 20-26. Watch the full video for more.