Variants of the coronavirus
The World Health Organization lists four SARS-CoV-2 strains as 'variants of concern'
| Variant | Earliest samples | No. of countries |
|---|---|---|
| Alpha | United Kingdom, Sep 2020 | 182 |
| Beta | South Africa, May 2020 | 132 |
| Gamma | Brazil, Nov 2020 | 81 |
| Delta | India, Oct 2020 | 135 |
