On May 31, 2023, the World Health Organization announced it had assigned simple, easy to say and remember labels for key variants of SARS-CoV-2, the virus that causes COVID-19, using letters of the Greek alphabet.

These labels were chosen after wide consultation and a review of many potential naming systems. WHO convened an expert group of partners from around the world to do so, including experts who are part of existing naming systems, nomenclature and virus taxonomic experts, researchers and national authorities.