Table S2. Associations between background characteristics and hesitancy to receive the first and second booster doses of the COVID-19 vaccine among 525 participants who completed the primary vaccination series.

Characteristic	Hesitancy to receive the first COVID-19 vaccine booster dose				Hesitancy to receive the second COVID-19 vaccine booster dose
	Prevalence of vaccine hesitancy n/N (%)	OR (95% CI)	P value		Prevalence of vaccine hesitancy n/N (%)	OR (95% CI)	P value
Abbreviation: COVID-19=coronavirus disease 2019; OR=crude odds ratio; CI=confidence interval.
Age group in years
18–45	29/87 (33.3)	1.0			48/87 (44.2)	1.0
46–60	68/219 (31.1)	0.90 (0.53, 1.53)	0.699		125/219 (57.1)	1.08 (0.66, 1.78)	0.762
61–75	62/194 (32.0)	0.94 (0.55, 1.61)	0.820		106/194 (54.6)	0.98 (0.59, 1.63)	0.934
>75	9/25 (36.0)	1.13 (0.44, 2.85)	0.804		17/25 (68.0)	1.73 (0.67, 4.42)	0.255
Gender
Male	93/293 (31.7)	1.0			151/293 (51.5)	1.0
Female	75/232 (32.3)	1.03 (0.71, 1.49)	0.886		145/232 (62.5)	1.57 (1.10, 2.23)	0.012
Ethnicity
Han majority	146/426 (34.3)	1.0			254/426 (59.6)	1.0
Other ethnic minority groups	22/99 (22.2)	0.55 (0.35, 0.92)	0.022		42/99 (42.4)	0.50 (0.32, 0.78)	0.002
Education level
Junior high school and below	112/338 (33.1)	1.0			198/338 (58.6)	1.0
High school education or equivalent	31/102 (30.4)	0.88 (0.55, 1.42)	0.604		54/102 (52.9)	0.80 (0.51, 1.24)	0.313
College-level and above	25/85 (29.4)	0.84 (0.50, 1.41)	0.512		44/85 (51.8)	0.76 (0.47, 1.22)	0.257
Relationship status
Single/divorced/widowed	10/39 (25.6)	1.0			20/39 (51.3)	1.0
Married	158/486 (32.5)	1.40 (0.66, 2.94)	0.378		276/486 (56.8)	1.25 (0.65, 2.40)	0.505
Employment status
Full-time	46/138 (33.3)	1.0			86/138 (62.3)	1.0
Part-time/self-employed/ Unemployed/retired/students	122/387 (31.5)	0.92 (0.61, 1.39)	0.696		210/387 (54.3)	0.72 (0.48, 1.07)	0.102
Type of cancer
Lung cancer	34/109 (31.2)	1.0			55/109 (50.5)	1.0
Gastric cancer	20/66 (30.3)	0.96 (0.49, 1.86)	0.902		36/66 (54.5)	1.18 (0.64, 2.18)	0.600
Liver cancer	6/15 (40.0)	1.47 (0.49, 4.46)	0.496		12/15 (80.0)	3.93 (1.05, 14.70)	0.042
Breast cancer	12/30 (40.0)	1.47 (0.64, 3.39)	0.366		24/30 (80.0)	3.93 (1.48, 10.36)	0.006
Colorectal cancer	39/97 (40.2)	1.48 (0.84, 2.63)	0.178		64/97 (66.0)	1.90 (1.08, 3.35)	0.025
Esophageal cancer	6/26 (23.1)	0.66 (0.24, 1.60)	0.418		12/26 (46.2)	0.84 (0.36, 1.98)	0.693
Ovarian cancer	13/43 (30.2)	0.96 (0.44, 2.06)	0.908		26/43 (60.5)	0.91 (0.55, 1.51)	0.724
Other types of cancer	39/139 (27.3)	0.83 (0.48, 1.44)	0.507		67/139 (48.2)	1.50 (0.73, 3.08)	0.267
Metastatic cancers
No	161/490 (32.9)	1.0			280/490 (57.1)	1.0
Yes	7/35 (20.0)	0.51 (0.22, 1.20)	0.121		16/35 (45.7)	0.63 (0.32, 1.26)	0.191
Current treatment for cancer
Untreated patients	4/17 (23.5)	1.0			10/17 (58.8)	1.0
Chemotherapy only	127/338 (37.6)	1.96 (0.62, 6.13)	0.250		212/338 (62.7)	1.18 (0.44, 3.17)	0.746
Radiotherapy only	14/89 (15.7)	0.61 (0.17, 2.13)	0.436		34/89 (38.2)	0.43 (0.15, 1.24)	0.120
Immunotherapy only	4/12 (33.3)	1.63 (0.32, 8.40)	0.562		6/12 (50.0)	0.70 (0.16, 3.10)	0.638
Chemotherapy and radiotherapy	7/34 (20.6)	0.84 (0.21, 3.40)	0.810		14/34 (41.2)	0.49 (0.15, 1.60)	0.237
Immunotherapy and chemotherapy/radiotherapy	5/15 (33.3)	1.63 (0.34, 7.67)	0.540		7/15 (46.7)	0.61 (0.15, 2.49)	0.493
Completion of treatment	7/20 (35.0)	1.75 (0.41, 7.45)	0.449		13/20 (65.0)	1.30 (0.34, 4.93)	0.700
Presence of any other chronic diseases
No	136/412 (33.0)	1.0			242/412 (58.7)	1.0
Yes	32/113 (28.3)	0.80 (0.51, 1.27)	0.344		54/113 (47.8)	0.64 (0.42, 0.98)	0.038