https://www.siliconvalley.com/2021/11/29/travel-restrictions-by-country-following-the-omicron-variant-outbreak/

Just as many countries around the world were beginning to loosen their border restrictions, reports of a newly detected coronavirus variant in South Africa sent many of those doors slamming shut again.

The new B.1.1.529 variant was named Omicron by the World Health Organization on November 26.