Table 1 Number of human SARS-CoV-2 strains in GISAID and the sample sizes included in this study for different periods
| Period | Number of strains | |
|---|---|---|
| in GISAID | in this study | |
| Jan 1–31 | 6 | 6 |
| Feb 1–29 | 16 | 16 |
| Mar 1–10 | 72 | 30 |
| Mar 11–20 | 94 | 30 |
| Mar 21–31 | 158 | 30 |
| Apr 1–10 | 100 | 30 |
| Apr 11–20 | 21 | 21 |
| Apr 21–30 | 50 | 30 |
| May 1–10 | 7 | 7 |
| Total | 524 | 199 |