SARS-CoV-2 Variants of Concern and Variants of Interest

The established nomenclature systems for naming and tracking SARS-CoV-2 genetic lineages by GISAID, Nextstrain and Pango are currently and will remain in use by scientists and in scientific research. To assist with public discussions of variants,
WHO convened a group of scientists from the WHO Virus Evolution Working Group, the WHO COVID-19 reference laboratory network, representatives from GISAID, Nextstrain, Pango and additional experts in virological, microbial nomenclature and communication from several countries and agencies to consider easy-to-pronounce and non-stigmatising labels for VOI and VOC. At the present time, this expert group convened by WHO has recommended using labeled using letters of the Greek Alphabet, i.e., Alpha, Beta, Gamma, which will be easier and more practical to discussed by non-scientific audiences.

Variants of Concern 

A SARS-CoV-2 variant that meets the definition of a VOI (see below) and, through a comparative assessment, has been demonstrated to be associated with one or more of the following changes at a degree of global public health significance: 

Increase in transmissibility or detrimental change in COVID-19 epidemiology; or 

Increase in virulence or change in clinical disease presentation; or 

Decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.  

WHO label	Pango lineage	GISAID clade/lineage	Nextstrain clade	Earliest documented samples	Date of designation
Alpha	B.1.1.7	GRY (formerly GR/501Y.V1)	20I/S:501Y.V1	United Kingdom,  Sep-2020	18-Dec-2020
Beta	B.1.351	GH/501Y.V2	20H/S:501Y.V2	South Africa,  May-2020	18-Dec-2020
Gamma	P.1	GR/501Y.V3	0J/S:501Y.V3	Brazil,  Nov-2020	11-Jan-2021
Delta	B.1.617.2	G/452R.V3	21A/S:478K	India,  Oct-2020	VOI: 4-Apr-2021 VOC: 11-May-2021

Variants of Interest 

A SARS-CoV-2 isolate is a Variant of Interest (VOI) if, compared to a reference isolate, its genome has mutations with established or suspected phenotypic implications, and either:  

has been identified to cause community transmission/multiple COVID-19 cases/clusters, or has been detected in multiple countries; OR  

is otherwise assessed to be a VOI by WHO in consultation with the WHO SARS-CoV-2 Virus Evolution Working Group. 

WHO label Earliest documented samples Date of designation 

Epsilon      United States of America, Mar-2020  5-Mar-2021 

Zeta     Brazil, Apr-2020                 17-Mar-2021 

Eta     Multiple countries, Dec-2020         17-Mar-2021

Theta     Philippines, Jan-2021         24-Mar-2021

Iota     United States of America, Nov-2020 24-Mar-2021

Kappa     India, Oct-2020                          4-Apr-2021 

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