SARS-CoV-2 variants are grouped according to their lineage and component mutations. Many organisations, including governments and news outlets, referred colloquially to concerning variants by the country in which they were first identified. After months of discussions, the World Health Organisation announced Greek Letter names for important strains on 31 May 2021, so they could be easily referred to in a simple, easy to say, and non-stigmatising fashion. This decision may have partially been taken because of criticism from governments on using country names to refer to variants of the virus; the WHO mentioned the potential for mentioning country names to cause stigma.
After using all the letters from Alpha to Mu, in November 2021 the WHO skipped the next two letters of the Greek alphabet, Nu and Xi, and used Omicron, prompting speculation that Xi was skipped to avoid offending Chinese leaderXi Jinping.The WHO gave as the explanation that Nu is too easily confounded with “new” and Xi is a common name. In the event that the WHO uses the entirety of the Greek alphabet, the agency considered naming future variants after constellations
Variants that appear to meet one or more specific criteria considered during the COVID-19 pandemic may be labeled “variants of interest” or “variants under investigation” (‘VUI’) pending verification and validation of these properties. Once validated, variants of interest /VUI may be renamed “variants of concern” by monitoring organizations, such as the CDC in the US.A related category is “variant of high consequence”, used by the CDC if there is clear evidence that the effectiveness of prevention or intervention measures for a particular variant is substantially reduced.
The SIG Variant classification scheme defines four classes of SARS-CoV-2 variants:
- Variant Being Monitored(VBM)
- Alpha (B.1.1.7 and Q lineages)
- Beta (B.1.351 and descendent lineages)
- Gamma (P.1 and descendent lineages)
- Delta (B.1.617.2 and AY lineages)
- Epsilon (B.1.427 and B.1.429)
- Eta (B.1.525)
- Iota (B.1.526)
- Kappa (B.1.617.1)
- 1.617.3
- Mu (B.1.621, B.1.621.1)
- Zeta (P.2)
These variants continue to be closely monitored to identify changes in their proportions and new data are continually being analyzed.
Source: Wikepedia