In 2023, WHO updated working definitions for SARS-CoV-2 Variants Under Monitoring (VUM), Variants of Interest (VOI), and Variants of Concern (VOC); a new variant meeting the VOC definition would receive a Greek letter designation, which has not happened since the emergence of Omicron.
Throughout the pandemic, Pango lineage nomenclature has been used to designate new viral lineages, which is a more granular categorization than a WHO variant; lineages continue to be proposed and designated routinely on the Pango-designation Github repository, following specific criteria for designation outlined by the Pango Network.