Table 1.

Baseline information of participants.

Characteristics	Herbal medicine group N = 11,092	Control group N = 10,973
Age, years
< 16 (No., %)	35 (0.32)	70 (0.64)
16–59 (No., %)	8,383 (75.58)	6,574 (59.92)
≥ 60 (No., %)	2,659 (23.97)	4,269 (38.91)
Gender
Male (No., %)	5,398 (48.67)	5,186 (47.27)
Female (No., %)	5,694 (51.33)	5,786 (52.73)
Had common cold or related symptoms during the screening period
Common cold symptoms (No., %)	2 (0.02)	8 (0.07)
Other related symptoms (No., %)	1 (0.01)	9 (0.08)
No symptoms (No., %)	11,089 (99.97)	10,956 (99.85)