Since SARS-CoV-2 first emerged in late 2019 the virus has spawned dozens of lineages, a handful of global "variants of concern" that changed the course of the pandemic.
Covid Variants Over Time: Alpha To Omicron To Stratus, Tracked And Explained

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Since SARS-CoV-2 first emerged in late 2019 the virus has spawned dozens of lineages, a handful of global "variants of concern" that changed the course of the pandemic.