Table 1. Characteristics of participants according to primary infection strain of SARS-CoV-2 (n=368).

Characteristic	Wild type infection			Alpha/Delta infection			Omicron infection			Total
	n	%		n	%		n	%		n	%
Abbreviation: SARS-CoV-2=severe acute respiratory syndrome coronavirus 2. * Only 325 respondents had access to detailed vaccination information.
Gender
Male	36	52.9		45	51.1		102	48.1		183	49.7
Female	32	47.1		43	48.9		110	51.9		185	50.3
Age, years
0–17	7	10.3		14	15.9		18	8.5		39	10.6
18–59	49	72.1		51	58.0		183	86.3		283	76.9
≥60	12	17.6		23	26.1		11	5.2		46	12.5
Occupation
Medical worker	4	5.9		3	3.4		20	9.4		27	7.3
Other	64	94.1		85	96.6		192	90.6		341	92.7
Clinical manifestation of primary infection
Asymptomatic	13	19.1		14	15.9		47	22.2		74	20.1
Symptomatic	55	80.9		74	84.1		165	77.8		294	79.9
SARS-CoV-2 vaccination status
Unvaccinated	0	0		4	4.5		4	1.9		8	2.2
Incomplete	7	10.3		9	10.2		9	4.2		25	6.8
Complete	12	17.6		39	44.3		52	24.5		103	28.0
Booster	34	50.0		34	38.6		121	57.1		189	51.4
No detail	15	22.1		2	2.3		26	12.3		43	11.7
Interval since last vaccination*
Unvaccinated	0	0.0		4	4.7		4	2.2		8	2.5
<12 months	26	49.1		74	86.0		50	26.9		150	46.2
≥12 months	27	50.9		8	9.3		132	71.0		167	51.4
Reinfection status
Non-reinfection	34	50.0		57	64.8		173	81.6		264	71.7
Reinfection	34	50.0		31	35.2		39	18.4		104	28.3
Probable case	7	10.3		6	6.8		21	9.9		34	9.2
Confirmed case	27	39.7		25	28.4		18	8.5		70	19.0