You may be familiar with SARS-CoV-2 variants named UK variant, South African variant, Brazilian variant, Indian variant, and so forth. Although these naming are easy to understand the variants closely rather than using virus strain names, it tends to put a stigma on those countries. Recently, it seems to be decided to use Greek letters to identify virus variants.
I have cited a figure showing mutations occurring in those variants from the following paper, and added relationships among several virus variants names as follows.
Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade
https://www.mdpi.com/1999-4915/13/7/1192/htm
Alpha（α）＝ B1.1.7 strain, UK variant
Beta（β）＝ B1.351 strain, South African variant
Gamma（γ）＝ P.1 strain, Brazilian variant
Delta（δ）＝ B.1.617 strain, Indian variant
other is for instance,
Epsilon（ε）＝B.1.427/29 strain, US variant
