The World Health Organisation called for countries to keep calm and take “rational” measures in response to the new, fast-spreading Covid variant Omicron, which has sparked global panic, AFP reports.

“We call on all member states to take rational, proportional risk-reduction measures,” WHO chief Tedros Adhanom Ghebreyesus said in a briefing to countries.

“We still have more questions than answers about the effect of Omicron on transmission, severity of disease, and the effectiveness of tests, therapeutics and vaccines,” he added.