What we know and don't know about Omicron variant

The World Health Organization says it could still take some time to get a full picture of the threat posed by Omicron, a new variant of the coronavirus as scientists worldwide scramble to assess its multiple mutations. Here's a look at we we know about the variant and why scientists are worried.

Stock markets swooned, some public gatherings got canceled, and countries across the globe suspended incoming flights after scientists in South Africa last week identified the new version that appears to have been behind a recent spike in COVID-19 infections in the country's most populous province.

Over the weekend, the list of countries that have spotted the new variant in travelers grew. Portugal detected 13 cases linked to the new variant among members of a single soccer club -- only one of whom had recently traveled to South Africa.

On Friday, WHO designated it as a "variant of concern," its most serious designation of a COVID-19 variant, and called it "Omicron" as the latest entry into its Greek alphabet classification system designed to avoid stigmatizing countries of origin and simplify understanding.

By Sunday, UN health agency issued a statement on Omicron that boiled down to: We don't know much yet.