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