Table 2. Comparison of the characteristics of seropositive-, seronegative- and undefined subjects.

	SARS-CoC-2 IgG antibody ratio groups
	seronegative (<0.8) n = 371	undefined (0.8–1.0) n = 3	seropositive (>1.0) n = 11
gender
male	72 (19%)	1 (33%)	4 (36%)
female	299 (81%)	2 (67%)	7 (64%)
age class
18–29 years	53 (14%)	1 (33%)	1 (9%)
30–49 years	146 (39%)	1 (33%)	7 (64%)
50–64 years	166 (45%)	1 (33%)	3 (27%)
>65 years	6 (2%)	-	-
professional group
nurse	154 (42%)	-	-
physician	31 (8%)	-	3 (27%)
therapist	75 (20%)	2 (67%)	3 (27%)
others	111 (30%)	1 (33%)	5 (46%)
subjects with infections	187 (50%)	2 (67%)	4 (36%)
time point of infection
January 2020	34 (9%)	-	1 (25%)
February 2020	64 (17%)	2 (67%)	-
March 2020	46 (12%)	-	3 (75%)
April 2020	20 (5%)	-	-
missing data	23 (6%)	-	-
symptoms
fever	41 (11%)	2 (67%)	2 (18%)
coughing	114 (31%)	2 (67%)	4 (36%)
respiratory distress	19 (5%)	1 (33%)	-
muscle/joint pain	73 (20%)	2 (67%)	1 (9%)
sore throat	119 (32%)	2 (67%)	2 (18%)
headaches	99 (26%)	2 (67%)	2 (18%)
nausea/vomiting	25 (7%)	-	2 (18%)
rhinitis	91 (24%)	1 (33%)	1 (9%)
diarrhea	32 (8%)	-	2 (18%)
medical condition
cardiovascular disease	66 (18%)	1 (33%)	2 (18%)
respiratory disease	37 (10%)	-	-
weakened immune system	17 (5%)	1 (33%)	-
diabetes mellitus	10 (3%)	-	1 (9%)
hepatic disease	2 (1%)	-	-
cancerous diseases	5 (1%)	-	-
abroad stay	38 (10%)	1 (33%)	1 (9%)