The many thousands of SARS-CoV-2 variants are grouped into either clades or lineages. The WHO has established nomenclature systems for naming and tracking SARS-CoV-2 genetic lineages and the labeling of variants using letters of the Greek Alphabet, for example, Alpha, Beta, Delta, and Gamma, because this "will be easier and more practical to discussed by non-scientific audiences.".

 

Several notable variants of SARS-CoV-2 emerged in late 2020. Cluster 5 emerged among minks and mink farmers in Denmark. After strict quarantines and a mink euthanasia campaign, it is believed to have been eradicated.

 

As of July 2021, there are four dominant variants of SARS-CoV-2 spreading among global populations: the Alpha Variant (formerly called the UK Variant and officially referred to as B.1.1.7), first found in London and Kent, the Beta Variant (formerly called the South Africa Variant and officially referred to as B.1.351), the Gamma Variant (formerly called the Brazil Variant and officially referred to as P.1), and the Delta Variant (formerly called the India Variant and officially referred to as B.1.617.2) that transmits more quickly than some other strains.