World J Oncol

World Journal of Oncology, ISSN 1920-4531 print, 1920-454X online, Open Access

Article copyright, the authors; Journal compilation copyright, World J Oncol and Elmer Press Inc

Journal website https://www.wjon.org

Original Article

Volume 13, Number 4, August 2022, pages 172-184

External Supports Are Associated With the COVID-19 Vaccination in Chinese Breast Cancer Patients: A Cross-Sectional Survey

**Table 1.** Characteristics of Study Population
	Unvaccinated	Vaccinated	P-value
HER2: human epidermal growth factor receptor type 2; COVID-19: coronavirus disease 2019.
No.	730	214
Age (years)	48.78 ± 8.74	50.00 ± 9.12	0.075
Time after surgery (days)	910.92 ± 681.51	1,272.64 ± 883.51	< 0.001
Surgical method			0.497
Mastectomy	452 (61.92%)	127 (59.35%)
Breast conserving surgery	278 (38.08%)	87 (40.65%)
Axillary lymph node dissection			< 0.001
Yes	403 (55.21%)	81 (37.85%)
No	327 (44.79%)	133 (62.15%)
Breast reconstruction surgery			0.305
No	659 (90.27%)	188 (87.85%)
Yes	71 (9.73%)	26 (12.15%)
Anti-HER2 therapy			0.081
No	563 (77.12%)	177 (82.71%)
Yes	167 (22.88%)	37 (17.29%)
Chemotherapy			< 0.001
Yes	503 (68.90%)	120 (56.07%)
No	227 (31.10%)	94 (43.93%)
Endocrinotherapy			0.984
Yes	594 (81.37%)	174 (81.31%)
No	136 (18.63%)	40 (18.69%)
Radiotherapy			0.047
Yes	441 (60.41%)	113 (52.80%)
No	289 (39.59%)	101 (47.20%)
Neoadjuvant therapy			0.062
No	630 (86.30%)	195 (91.12%)
Yes	100 (13.70%)	19 (8.88%)
Undergoing treatment			0.085
Yes	480 (65.75%)	127 (59.35%)
No	250 (34.25%)	87 (40.65%)
Current treatment method			< 0.001
No treatment	250 (34.25%)	87 (40.65%)
Endocrinotherapy	307 (42.05%)	109 (50.93%)
Others	158 (21.64%)	17 (7.94%)
Traditional Chinese medicine	15 (2.05%)	1 (0.47%)
Recurrence of breast cancer before vaccination			0.282
No	706 (96.71%)	210 (98.13%)
Yes	24 (3.29%)	4 (1.87%)
Personal COVID-19 history			0.45
No	718 (98.36%)	212 (99.07%)
Yes	12 (1.64%)	2 (0.93%)
Educational level			0.923
Higher than high school	504 (69.04%)	147 (68.69%)
High school and lower	226 (30.96%)	67 (31.31%)
Employment status			0.153
Yes	386 (52.88%)	125 (58.41%)
No	344 (47.12%)	89 (41.59%)
Influenza vaccination history			< 0.001
Never	617 (84.52%)	162 (75.70%)
At least once in 3 years	61 (8.36%)	39 (18.22%)
At least once in 10 years	52 (7.12%)	13 (6.07%)
Yearly personal income (Chinese Yuan)			0.012
≥ 50,000	397 (54.38%)	137 (64.02%)
< 5,0000	333 (45.62%)	77 (35.98%)
Marital status			0.759
Married	639 (87.53%)	189 (88.32%)
Unmarried	91 (12.47%)	25 (11.68%)
Region of living in China			0.056
North China	445 (60.96%)	136 (63.55%)
East China	118 (16.16%)	32 (14.95%)
Northeast China	66 (9.04%)	19 (8.88%)
Central China	37 (5.07%)	9 (4.21%)
South China	28 (3.84%)	12 (5.61%)
West China	36 (4.93%)	4 (1.87%)
Others	0 (0.00%)	2 (0.93%)
Place of residence			0.611
Urban area	653 (89.45%)	194 (90.65%)
Rural area	77 (10.55%)	20 (9.35%)
Vaccination suggestion from surgeon or oncologist			< 0.001
Indefinite suggestion	319 (43.70%)	81 (37.85%)
No communication with doctors	231 (31.64%)	40 (18.69%)
Recommended	60 (8.22%)	85 (39.72%)
Not recommended	120 (16.44%)	8 (3.74%)
Vaccination suggestion from around people			< 0.001
No suggestion	398 (54.52%)	36 (16.82%)
Recommended	161 (22.05%)	168 (78.50%)
Not recommended	171 (23.42%)	10 (4.67%)
Calls for vaccination by the residents’ committee or employer			< 0.001
Yes	407 (55.75%)	184 (85.98%)
No vaccinal notice	213 (29.18%)	24 (11.21%)
No	110 (15.07%)	6 (2.80%)

Table 1. Characteristics of Study Population

Unvaccinated

Vaccinated

P-value

HER2: human epidermal growth factor receptor type 2; COVID-19: coronavirus disease 2019.

No.

730

214

Age (years)

48.78 ± 8.74

50.00 ± 9.12

0.075

Time after surgery (days)

910.92 ± 681.51

1,272.64 ± 883.51

< 0.001

Surgical method

0.497

Mastectomy

452 (61.92%)

127 (59.35%)

Breast conserving surgery

278 (38.08%)

87 (40.65%)

Axillary lymph node dissection

< 0.001

Yes

403 (55.21%)

81 (37.85%)

327 (44.79%)

133 (62.15%)

Breast reconstruction surgery

0.305

659 (90.27%)

188 (87.85%)

Yes

71 (9.73%)

26 (12.15%)

Anti-HER2 therapy

0.081

563 (77.12%)

177 (82.71%)

Yes

167 (22.88%)

37 (17.29%)

Chemotherapy

< 0.001

Yes

503 (68.90%)

120 (56.07%)

227 (31.10%)

94 (43.93%)

Endocrinotherapy

0.984

Yes

594 (81.37%)

174 (81.31%)

136 (18.63%)

40 (18.69%)

Radiotherapy

0.047

Yes

441 (60.41%)

113 (52.80%)

289 (39.59%)

101 (47.20%)

Neoadjuvant therapy

0.062

630 (86.30%)

195 (91.12%)

Yes

100 (13.70%)

19 (8.88%)

Undergoing treatment

0.085

Yes

480 (65.75%)

127 (59.35%)

250 (34.25%)

87 (40.65%)

Current treatment method

< 0.001

No treatment

250 (34.25%)

87 (40.65%)

Endocrinotherapy

307 (42.05%)

109 (50.93%)

Others

158 (21.64%)

17 (7.94%)

Traditional Chinese medicine

15 (2.05%)

1 (0.47%)

Recurrence of breast cancer before vaccination

0.282

706 (96.71%)

210 (98.13%)

Yes

24 (3.29%)

4 (1.87%)

Personal COVID-19 history

0.45

718 (98.36%)

212 (99.07%)

Yes

12 (1.64%)

2 (0.93%)

Educational level

0.923

Higher than high school

504 (69.04%)

147 (68.69%)

High school and lower

226 (30.96%)

67 (31.31%)

Employment status

0.153

Yes

386 (52.88%)

125 (58.41%)

344 (47.12%)

89 (41.59%)

Influenza vaccination history

< 0.001

Never

617 (84.52%)

162 (75.70%)

At least once in 3 years

61 (8.36%)

39 (18.22%)

At least once in 10 years

52 (7.12%)

13 (6.07%)

Yearly personal income (Chinese Yuan)

0.012

≥ 50,000

397 (54.38%)

137 (64.02%)

< 5,0000

333 (45.62%)

77 (35.98%)

Marital status

0.759

Married

639 (87.53%)

189 (88.32%)

Unmarried

91 (12.47%)

25 (11.68%)

Region of living in China

0.056

North China

445 (60.96%)

136 (63.55%)

East China

118 (16.16%)

32 (14.95%)

Northeast China

66 (9.04%)

19 (8.88%)

Central China

37 (5.07%)

9 (4.21%)

South China

28 (3.84%)

12 (5.61%)

West China

36 (4.93%)

4 (1.87%)

Others

0 (0.00%)

2 (0.93%)

Place of residence

0.611

Urban area

653 (89.45%)

194 (90.65%)

Rural area

77 (10.55%)

20 (9.35%)

Vaccination suggestion from surgeon or oncologist

< 0.001

Indefinite suggestion

319 (43.70%)

81 (37.85%)

No communication with doctors

231 (31.64%)

40 (18.69%)

Recommended

60 (8.22%)

85 (39.72%)

Not recommended

120 (16.44%)

8 (3.74%)

Vaccination suggestion from around people

< 0.001

No suggestion

398 (54.52%)

36 (16.82%)

Recommended

161 (22.05%)

168 (78.50%)

Not recommended

171 (23.42%)

10 (4.67%)

Calls for vaccination by the residents’ committee or employer

< 0.001

Yes

407 (55.75%)

184 (85.98%)

No vaccinal notice

213 (29.18%)

24 (11.21%)

110 (15.07%)

6 (2.80%)

**Table 2.** Univariate Analysis of Factors Associated With COVID-19 Vaccination Among Breast Cancer Patients
	Statistics	OR (95% CI)	P-value
HER2: human epidermal growth factor receptor type 2; COVID-19: coronavirus disease 2019: OR: odds ratio; CI: confidence interval.
Age (years)	49.05 ± 8.84	1.02 (1.00 - 1.03)	0.0751
Time after surgery
Q1	235 (25.00%)	1
Q2	233 (24.79%)	1.35 (0.82 - 2.24)	0.2366
Q3	236 (25.11%)	2.02 (1.25 - 3.26)	0.0039
Q4	236 (25.11%)	3.38 (2.13 - 5.35)	< 0.0001
Surgical method
Mastectomy	579 (61.33%)	1
Breast conserving surgery	365 (38.67%)	1.11 (0.82 - 1.52)	0.497
Axillary lymph node dissection
Yes	484 (51.27%)	1
No	460 (48.73%)	2.02 (1.48 - 2.77)	< 0.0001
Breast reconstruction surgery
No	847 (89.72%)	1
Yes	97 (10.28%)	1.28 (0.80 - 2.07)	0.3055
Anti-HER2 therapy
No	740 (78.39%)	1
Yes	204 (21.61%)	0.70 (0.48 - 1.05)	0.0818
Chemotherapy
Yes	623 (66.00%)	1
No	321 (34.00%)	1.74 (1.27 - 2.37)	0.0005
Endocrinotherapy
Yes	768 (81.36%)	1
No	176 (18.64%)	1.00 (0.68 - 1.48)	0.9838
Radiotherapy
Yes	554 (58.69%)	1
No	390 (41.31%)	1.36 (1.00 - 1.85)	0.0473
Neoadjuvant therapy
No	825 (87.39%)	1
Yes	119 (12.61%)	0.61 (0.37 - 1.03)	0.0639
Current treatment
Yes	607 (64.30%)	1
No	337 (35.70%)	1.32 (0.96 - 1.80)	0.0858
Current treatment method
No treatment	337 (35.70%)	1
Endocrine	416 (44.07%)	1.02 (0.74 - 1.42)	0.9045
Others	175 (18.54%)	0.31 (0.18 - 0.54)	< 0.0001
Traditional Chinese medicine	16 (1.69%)	0.19 (0.02 - 1.47)	0.1122
Recurrence of breast cancer before vaccination
No	916 (97.03%)	1
Yes	28 (2.97%)	0.56 (0.19 - 1.63)	0.2885
Personal COVID-19 history
No	930 (98.52%)	1
Yes	14 (1.48%)	0.56 (0.13 - 2.54)	0.4563
Educational level
Higher than high school	651 (68.96%)	1
High school or lower	293 (31.04%)	1.02 (0.73 - 1.41)	0.9226
Employment status
Yes	511 (54.13%)	1
No	433 (45.87%)	0.80 (0.59 - 1.09)	0.1535
Influenza vaccination history
Never	779 (82.52%)	1
At least once in 3 years	100 (10.59%)	2.44 (1.57 - 3.77)	< 0.0001
At least once in 10 years	65 (6.89%)	0.95 (0.51 - 1.79)	0.8791
Yearly personal income (Chinese Yuan)
≥ 50,000	534 (56.57%)	1
< 5,0000	410 (43.43%)	0.67 (0.49 - 0.92)	0.0127
Marital status
Married	828 (87.71%)	1
Unmarried	116 (12.29%)	0.93 (0.58 - 1.49)	0.7589
Region of living in China
North China	581 (61.55%)	1
East China	150 (15.89%)	0.89 (0.57 - 1.37)	0.5904
Northeast China	85 (9.00%)	0.94 (0.55 - 1.62)	0.8298
Central China	46 (4.87%)	0.80 (0.37 - 1.69)	0.5526
South China	40 (4.24%)	1.40 (0.69 - 2.83)	0.3458
West China	40 (4.24%)	0.36 (0.13 - 1.04)	0.0591
Others	2 (0.21%)	NA	NA
Place of residence
Urban area	847 (89.72%)	1
Rural area	97 (10.28%)	0.87 (0.52 - 1.47)	0.6108
Vaccination suggestion from surgeon or oncologist
Indefinite suggestion	400 (42.37%)	1
No communication with doctors	271 (28.71%)	0.68 (0.45 - 1.03)	0.0706
Recommended	145 (15.36%)	5.58 (3.70 - 8.41)	< 0.0001
Not recommended	128 (13.56%)	0.26 (0.12 - 0.56)	0.0005
Vaccination suggestion from around people
No suggestion	434 (45.97%)	1
Recommended	329 (34.85%)	11.54 (7.70 - 17.28)	< 0.0001
Not recommended	181 (19.17%)	0.65 (0.31 - 1.33)	0.2372
Calls for vaccination by the residents’ committee or employer
Yes	591 (62.61%)	1
No vaccinal notice	237 (25.11%)	0.25 (0.16 - 0.39)	< 0.0001
No	116 (12.29%)	0.12 (0.05 - 0.28)	< 0.0001

Table 2. Univariate Analysis of Factors Associated With COVID-19 Vaccination Among Breast Cancer Patients

Statistics

OR (95% CI)

P-value

HER2: human epidermal growth factor receptor type 2; COVID-19: coronavirus disease 2019: OR: odds ratio; CI: confidence interval.

Age (years)

49.05 ± 8.84

1.02 (1.00 - 1.03)

0.0751

Time after surgery

235 (25.00%)

233 (24.79%)

1.35 (0.82 - 2.24)

0.2366

236 (25.11%)

2.02 (1.25 - 3.26)

0.0039

236 (25.11%)

3.38 (2.13 - 5.35)

< 0.0001

Surgical method

Mastectomy

579 (61.33%)

Breast conserving surgery

365 (38.67%)

1.11 (0.82 - 1.52)

0.497

Axillary lymph node dissection

Yes

484 (51.27%)

460 (48.73%)

2.02 (1.48 - 2.77)

< 0.0001

Breast reconstruction surgery

847 (89.72%)

Yes

97 (10.28%)

1.28 (0.80 - 2.07)

0.3055

Anti-HER2 therapy

740 (78.39%)

Yes

204 (21.61%)

0.70 (0.48 - 1.05)

0.0818

Chemotherapy

Yes

623 (66.00%)

321 (34.00%)

1.74 (1.27 - 2.37)

0.0005

Endocrinotherapy

Yes

768 (81.36%)

176 (18.64%)

1.00 (0.68 - 1.48)

0.9838

Radiotherapy

Yes

554 (58.69%)

390 (41.31%)

1.36 (1.00 - 1.85)

0.0473

Neoadjuvant therapy

825 (87.39%)

Yes

119 (12.61%)

0.61 (0.37 - 1.03)

0.0639

Current treatment

Yes

607 (64.30%)

337 (35.70%)

1.32 (0.96 - 1.80)

0.0858

Current treatment method

No treatment

337 (35.70%)

Endocrine

416 (44.07%)

1.02 (0.74 - 1.42)

0.9045

Others

175 (18.54%)

0.31 (0.18 - 0.54)

< 0.0001

Traditional Chinese medicine

16 (1.69%)

0.19 (0.02 - 1.47)

0.1122

Recurrence of breast cancer before vaccination

916 (97.03%)

Yes

28 (2.97%)

0.56 (0.19 - 1.63)

0.2885

Personal COVID-19 history

930 (98.52%)

Yes

14 (1.48%)

0.56 (0.13 - 2.54)

0.4563

Educational level

Higher than high school

651 (68.96%)

High school or lower

293 (31.04%)

1.02 (0.73 - 1.41)

0.9226

Employment status

Yes

511 (54.13%)

433 (45.87%)

0.80 (0.59 - 1.09)

0.1535

Influenza vaccination history

Never

779 (82.52%)

At least once in 3 years

100 (10.59%)

2.44 (1.57 - 3.77)

< 0.0001

At least once in 10 years

65 (6.89%)

0.95 (0.51 - 1.79)

0.8791

Yearly personal income (Chinese Yuan)

≥ 50,000

534 (56.57%)

< 5,0000

410 (43.43%)

0.67 (0.49 - 0.92)

0.0127

Marital status

Married

828 (87.71%)

Unmarried

116 (12.29%)

0.93 (0.58 - 1.49)

0.7589

Region of living in China

North China

581 (61.55%)

East China

150 (15.89%)

0.89 (0.57 - 1.37)

0.5904

Northeast China

85 (9.00%)

0.94 (0.55 - 1.62)

0.8298

Central China

46 (4.87%)

0.80 (0.37 - 1.69)

0.5526

South China

40 (4.24%)

1.40 (0.69 - 2.83)

0.3458

West China

40 (4.24%)

0.36 (0.13 - 1.04)

0.0591

Others

2 (0.21%)

Place of residence

Urban area

847 (89.72%)

Rural area

97 (10.28%)

0.87 (0.52 - 1.47)

0.6108

Vaccination suggestion from surgeon or oncologist

Indefinite suggestion

400 (42.37%)

No communication with doctors

271 (28.71%)

0.68 (0.45 - 1.03)

0.0706

Recommended

145 (15.36%)

5.58 (3.70 - 8.41)

< 0.0001

Not recommended

128 (13.56%)

0.26 (0.12 - 0.56)

0.0005

Vaccination suggestion from around people

No suggestion

434 (45.97%)

Recommended

329 (34.85%)

11.54 (7.70 - 17.28)

< 0.0001

Not recommended

181 (19.17%)

0.65 (0.31 - 1.33)

0.2372

Calls for vaccination by the residents’ committee or employer

Yes

591 (62.61%)

No vaccinal notice

237 (25.11%)

0.25 (0.16 - 0.39)

< 0.0001

116 (12.29%)

0.12 (0.05 - 0.28)

< 0.0001

**Table 3.** Relationship Between External Supports and COVID-19 Vaccination in Different Models
Exposure	Crude model (OR (95% CI), P-value)	Minimally adjusted model (OR (95% CI), P-value)	Fully adjusted model (OR (95% CI), P-value)
Non-adjusted model adjusted for: none. Minimally adjusted model: we adjusted for age; yearly personal income; educational level; employment status. Fully adjusted model: we adjusted for age; time after surgery; surgical method; axillary lymph node dissection; breast reconstruction surgery; anti-HER2 therapy; chemotherapy; endocrinotherapy; radiotherapy; neoadjuvant therapy; undergoing treatment; recurrence of breast cancer before vaccination; personal COVID-19 history; educational level; employment; influenza vaccination history; yearly personal income; marital status; region of living in China; place of residence. OR: odds ratio; CI: confidence interval; Ref: reference.
Vaccination suggestion from surgeon or oncologist
Indefinite suggestion	Ref	Ref	Ref
No communication with doctors	0.68 (0.45 - 1.03), 0.0706	0.68 (0.45 - 1.04), 0.0757	0.80 (0.52 - 1.24), 0.3149
Recommended	5.58 (3.70 - 8.41), < 0.0001	5.44 (3.57 - 8.27), < 0.0001	5.52 (3.50 - 8.71), < 0.0001
Not recommended	0.26 (0.12 - 0.56), 0.0005	0.27 (0.12 - 0.57), 0.0007	0.36 (0.16 - 0.79), 0.0107
Vaccination suggestion from around people
No suggestion	Ref	Ref	Ref
Recommended	11.54 (7.70 - 17.28), < 0.0001	11.37 (7.58 - 17.06), < 0.0001	11.65 (7.57 - 17.91), < 0.0001
Not recommended	0.65 (0.31 - 1.33), 0.2372	0.64 (0.31 - 1.32), 0.2262	0.66 (0.31 - 1.42), 0.2885
Calls for vaccination by the residents’ committee or employer
Yes	Ref	Ref	Ref
No vaccinal notice	0.25 (0.16 - 0.39), < 0.0001	0.25 (0.16 - 0.40), < 0.0001	0.26 (0.16 - 0.42), < 0.0001
No	0.12 (0.05 - 0.28), < 0.0001	0.12 (0.05 - 0.28), < 0.0001	0.15 (0.06 - 0.35), < 0.0001

Table 3. Relationship Between External Supports and COVID-19 Vaccination in Different Models

Exposure

Crude model (OR (95% CI), P-value)

Minimally adjusted model (OR (95% CI), P-value)

Fully adjusted model (OR (95% CI), P-value)

Non-adjusted model adjusted for: none. Minimally adjusted model: we adjusted for age; yearly personal income; educational level; employment status. Fully adjusted model: we adjusted for age; time after surgery; surgical method; axillary lymph node dissection; breast reconstruction surgery; anti-HER2 therapy; chemotherapy; endocrinotherapy; radiotherapy; neoadjuvant therapy; undergoing treatment; recurrence of breast cancer before vaccination; personal COVID-19 history; educational level; employment; influenza vaccination history; yearly personal income; marital status; region of living in China; place of residence. OR: odds ratio; CI: confidence interval; Ref: reference.

Vaccination suggestion from surgeon or oncologist

Indefinite suggestion

Ref

No communication with doctors

0.68 (0.45 - 1.03), 0.0706

0.68 (0.45 - 1.04), 0.0757

0.80 (0.52 - 1.24), 0.3149

Recommended

5.58 (3.70 - 8.41), < 0.0001

5.44 (3.57 - 8.27), < 0.0001

5.52 (3.50 - 8.71), < 0.0001

Not recommended

0.26 (0.12 - 0.56), 0.0005

0.27 (0.12 - 0.57), 0.0007

0.36 (0.16 - 0.79), 0.0107

Vaccination suggestion from around people

No suggestion

Ref

Recommended

11.54 (7.70 - 17.28), < 0.0001

11.37 (7.58 - 17.06), < 0.0001

11.65 (7.57 - 17.91), < 0.0001

Not recommended

0.65 (0.31 - 1.33), 0.2372

0.64 (0.31 - 1.32), 0.2262

0.66 (0.31 - 1.42), 0.2885

Calls for vaccination by the residents’ committee or employer

Yes

Ref

No vaccinal notice

0.25 (0.16 - 0.39), < 0.0001

0.25 (0.16 - 0.40), < 0.0001

0.26 (0.16 - 0.42), < 0.0001

0.12 (0.05 - 0.28), < 0.0001

0.15 (0.06 - 0.35), < 0.0001

**Table 4.** Effect Size of External Supports on COVID-19 Vaccination in Prespecified and Exploratory Subgroups
Variables	No.	OR (95% CI), P-value	No.	OR (95% CI), P-value	P for interaction
Above model adjusted for age; time after surgery; surgical method; axillary lymph node dissection; breast reconstruction surgery; anti-HER2 therapy; chemotherapy; endocrinotherapy; radiotherapy; neoadjuvant therapy; undergoing treatment; recurrence of breast cancer before vaccination; personal COVID-19 history; educational level; employment; influenza vaccination history; yearly personal income; marital status; region of living in China; place of residence. In each case, the model is not adjusted for the stratification variable. OR: odds ratio; CI: confidence interval; HER2: human epidermal growth factor receptor type 2.
Vaccination suggestion from surgeon or oncologist
Age dichotomous	Age = low		Age = high		0.922
Indefinite suggestion	157	1	243	1
No communication with doctors	142	0.76 (0.38 - 1.51), 0.4299	129	0.86 (0.48 - 1.57), 0.6324
Recommended	68	5.35 (2.58 - 11.10), < 0.0001	77	6.20 (3.31 - 11.62), < 0.0001
Not recommended	68	0.39 (0.13 - 1.14), 0.0859	60	0.26 (0.07 - 0.91), 0.0350
	Time after surgery = short		Time after surgery = long		0.201
Indefinite suggestion	179	1	218	1
No communication with doctors	146	1.29 (0.61 - 2.73), 0.5077	124	0.63 (0.35 - 1.14), 0.1289
Recommended	58	12.36 (5.35 - 28.57), < 0.0001	87	4.56 (2.46 - 8.46), < 0.0001
Not recommended	85	0.67 (0.22 - 2.04), 0.4749	43	0.21 (0.06 - 0.76), 0.0178
	Axillary lymph node dissection = yes		Axillary lymph node dissection = no		0.762
Indefinite suggestion	209	1	191	1
No communication with doctors	146	0.89 (0.45 - 1.78), 0.7412	125	0.74 (0.41 - 1.33), 0.3151
Recommended	63	5.84 (2.81 - 12.14), < 0.0001	82	5.89 (3.17 - 10.95), < 0.0001
Not recommended	66	0.54 (0.17 - 1.68), 0.2867	62	0.23 (0.07 - 0.71), 0.0104
	Chemotherapy = yes		Chemotherapy = no		0.331
Indefinite suggestion	246	1	154	1
No communication with doctors	188	0.69 (0.37 - 1.27), 0.2288	83	0.81 (0.41 - 1.60), 0.5405
Recommended	94	6.79 (3.62 - 12.74), < 0.0001	51	3.19 (1.51 - 6.73), 0.0024
Not recommended	95	0.41 (0.15 - 1.16), 0.0927	33	0.23 (0.06 - 0.88), 0.0320
	Yearly personal income ≥ 50,000		Yearly personal income < 50,000		0.927
Indefinite suggestion	216	1	184	1
No communication with doctors	152	0.72 (0.41 - 1.29), 0.2750	119	0.88 (0.43 - 1.80), 0.7174
Recommended	100	5.68 (3.21 - 10.05), < 0.0001	45	5.66 (2.44 - 13.14), < 0.0001
Not recommended	66	0.28 (0.09 - 0.84), 0.0234	62	0.45 (0.13 - 1.48), 0.1868
Vaccination suggestion from around people
Age dichotomous	Age = low		Age = high		0.600
No suggestion	205	1	229	1
Recommended	141	12.58 (6.36 - 24.88), < 0.0001	188	12.85 (7.01 - 23.56), < 0.0001
Not recommended	89	0.90 (0.32 - 2.55), 0.8409	92	0.41 (0.12 - 1.46), 0.1687
	Time after surgery = short		Time after surgery = long		0.853
No suggestion	217	1	216	1
Recommended	149	13.90 (6.30 - 30.67), <0.0001	179	11.78 (6.72 - 20.65), < 0.0001
Not recommended	102	0.56 (0.14 - 2.21), 0.4052	77	0.68 (0.26 - 1.79), 0.4343
	Axillary lymph node dissection = yes		Axillary lymph node dissection = no		0.241
No suggestion	235	1	199	1
Recommended	142	8.27 (4.38 - 15.64), < 0.0001	187	17.19 (9.15 - 32.30), < 0.0001
Not recommended	107	0.40 (0.11 - 1.44), 0.1607	74	0.97 (0.36 - 2.63), 0.9491
	Chemotherapy = yes		Chemotherapy = no		0.907
No suggestion	302	1	132	1
Recommended	191	12.16 (6.72 - 22.02), < 0.0001	138	12.77 (6.09 - 26.80), < 0.0001
Not recommended	130	0.59 (0.21 - 1.66), 0.3166	51	0.84 (0.25 - 2.84), 0.7794
	Yearly personal income ≥ 50,000		Yearly personal income < 50,000		0.736
No suggestion	235	1	199	1
Recommended	202	13.78 (7.73 - 24.57), < 0.0001	127	10.47 (5.20 - 21.08), < 0.0001
Not recommended	97	0.79 (0.30 - 2.10), 0.6396	84	0.45 (0.12 - 1.70), 0.2375
Calls for vaccination by the residents’ committee or employer
Age dichotomous	Age = low		Age = high		0.421
Yes	293	1	298	1
No vaccinal notice	87	0.37 (0.18 - 0.79), 0.0104	150	0.19 (0.10 - 0.38), < 0.0001
No	55	0.12 (0.03 - 0.53), 0.0050	61	0.16 (0.05 - 0.46), 0.0008
	Time after surgery = short		Time after surgery = long		0.283
Yes	282	1	308	1
No vaccinal notice	115	0.18 (0.07 - 0.44), 0.0002	120	0.26 (0.14 - 0.48), < 0.0001
No	71	0.05 (0.01 - 0.36), 0.0034	44	0.22 (0.08 - 0.61), 0.0036
	Axillary lymph node dissection = yes		Axillary lymph node dissection = no		0.331
Yes	274	1	317	1
No vaccinal notice	140	0.28 (0.13 - 0.58), 0.0006	97	0.18 (0.08 - 0.37), < 0.0001
No	70	0.23 (0.08 - 0.69), 0.0090	46	0.07 (0.01 - 0.29), 0.0004
	Chemotherapy = yes		Chemotherapy = no		0.801
Yes	370	1	221	1
No vaccinal notice	165	0.30 (0.16 - 0.58), 0.0004	72	0.21 (0.09 - 0.49), 0.0003
No	88	0.15 (0.05 - 0.45), 0.0007	28	0.15 (0.03 - 0.69), 0.0150
	Yearly personal income ≥ 50,000		Yearly personal income < 50,000		0.932
Yes	367	1	224	1
No vaccinal notice	107	0.23 (0.12 - 0.46), < 0.0001	130	0.25 (0.12 - 0.54), 0.0004
No	60	0.12 (0.04 - 0.40), 0.0006	56	0.17 (0.05 - 0.60), 0.0059

Table 4. Effect Size of External Supports on COVID-19 Vaccination in Prespecified and Exploratory Subgroups

Variables

No.

OR (95% CI), P-value

No.

OR (95% CI), P-value

P for interaction

Above model adjusted for age; time after surgery; surgical method; axillary lymph node dissection; breast reconstruction surgery; anti-HER2 therapy; chemotherapy; endocrinotherapy; radiotherapy; neoadjuvant therapy; undergoing treatment; recurrence of breast cancer before vaccination; personal COVID-19 history; educational level; employment; influenza vaccination history; yearly personal income; marital status; region of living in China; place of residence. In each case, the model is not adjusted for the stratification variable. OR: odds ratio; CI: confidence interval; HER2: human epidermal growth factor receptor type 2.

Vaccination suggestion from surgeon or oncologist

Age dichotomous

Age = low

Age = high

0.922

Indefinite suggestion

157

243

No communication with doctors

142

0.76 (0.38 - 1.51), 0.4299

129

0.86 (0.48 - 1.57), 0.6324

Recommended

5.35 (2.58 - 11.10), < 0.0001

6.20 (3.31 - 11.62), < 0.0001

Not recommended

0.39 (0.13 - 1.14), 0.0859

0.26 (0.07 - 0.91), 0.0350

Time after surgery = short

Time after surgery = long

0.201

Indefinite suggestion

179

218

No communication with doctors

146

1.29 (0.61 - 2.73), 0.5077

124

0.63 (0.35 - 1.14), 0.1289

Recommended

12.36 (5.35 - 28.57), < 0.0001

4.56 (2.46 - 8.46), < 0.0001

Not recommended

0.67 (0.22 - 2.04), 0.4749

0.21 (0.06 - 0.76), 0.0178

Axillary lymph node dissection = yes

Axillary lymph node dissection = no

0.762

Indefinite suggestion

209

191

No communication with doctors

146

0.89 (0.45 - 1.78), 0.7412

125

0.74 (0.41 - 1.33), 0.3151

Recommended

5.84 (2.81 - 12.14), < 0.0001

5.89 (3.17 - 10.95), < 0.0001

Not recommended

0.54 (0.17 - 1.68), 0.2867

0.23 (0.07 - 0.71), 0.0104

Chemotherapy = yes

Chemotherapy = no

0.331

Indefinite suggestion

246

154

No communication with doctors

188

0.69 (0.37 - 1.27), 0.2288

0.81 (0.41 - 1.60), 0.5405

Recommended

6.79 (3.62 - 12.74), < 0.0001

3.19 (1.51 - 6.73), 0.0024

Not recommended

0.41 (0.15 - 1.16), 0.0927

0.23 (0.06 - 0.88), 0.0320

Yearly personal income ≥ 50,000

Yearly personal income < 50,000

0.927

Indefinite suggestion

216

184

No communication with doctors

152

0.72 (0.41 - 1.29), 0.2750

119

0.88 (0.43 - 1.80), 0.7174

Recommended

100

5.68 (3.21 - 10.05), < 0.0001

5.66 (2.44 - 13.14), < 0.0001

Not recommended

0.28 (0.09 - 0.84), 0.0234

0.45 (0.13 - 1.48), 0.1868

Vaccination suggestion from around people

Age dichotomous

Age = low

Age = high

0.600

No suggestion

205

229

Recommended

141

12.58 (6.36 - 24.88), < 0.0001

188

12.85 (7.01 - 23.56), < 0.0001

Not recommended

0.90 (0.32 - 2.55), 0.8409

0.41 (0.12 - 1.46), 0.1687

Time after surgery = short

Time after surgery = long

0.853

No suggestion

217

216

Recommended

149

13.90 (6.30 - 30.67), <0.0001

179

11.78 (6.72 - 20.65), < 0.0001

Not recommended

102

0.56 (0.14 - 2.21), 0.4052

0.68 (0.26 - 1.79), 0.4343

Axillary lymph node dissection = yes

Axillary lymph node dissection = no

0.241

No suggestion

235

199

Recommended

142

8.27 (4.38 - 15.64), < 0.0001

187

17.19 (9.15 - 32.30), < 0.0001

Not recommended

107

0.40 (0.11 - 1.44), 0.1607

0.97 (0.36 - 2.63), 0.9491

Chemotherapy = yes

Chemotherapy = no

0.907

No suggestion

302

132

Recommended

191

12.16 (6.72 - 22.02), < 0.0001

138

12.77 (6.09 - 26.80), < 0.0001

Not recommended

130

0.59 (0.21 - 1.66), 0.3166

0.84 (0.25 - 2.84), 0.7794

Yearly personal income ≥ 50,000

Yearly personal income < 50,000

0.736

No suggestion

235

199

Recommended

202

13.78 (7.73 - 24.57), < 0.0001

127

10.47 (5.20 - 21.08), < 0.0001

Not recommended

0.79 (0.30 - 2.10), 0.6396

0.45 (0.12 - 1.70), 0.2375

Calls for vaccination by the residents’ committee or employer

Age dichotomous

Age = low

Age = high

0.421

Yes

293

298

No vaccinal notice

0.37 (0.18 - 0.79), 0.0104

150

0.19 (0.10 - 0.38), < 0.0001

0.12 (0.03 - 0.53), 0.0050

0.16 (0.05 - 0.46), 0.0008

Time after surgery = short

Time after surgery = long

0.283

Yes

282

308

No vaccinal notice

115

0.18 (0.07 - 0.44), 0.0002

120

0.26 (0.14 - 0.48), < 0.0001

0.05 (0.01 - 0.36), 0.0034

0.22 (0.08 - 0.61), 0.0036

Axillary lymph node dissection = yes

Axillary lymph node dissection = no

0.331

Yes

274

317

No vaccinal notice

140

0.28 (0.13 - 0.58), 0.0006

0.18 (0.08 - 0.37), < 0.0001

0.23 (0.08 - 0.69), 0.0090

0.07 (0.01 - 0.29), 0.0004

Chemotherapy = yes

Chemotherapy = no

0.801

Yes

370

221

No vaccinal notice

165

0.30 (0.16 - 0.58), 0.0004

0.21 (0.09 - 0.49), 0.0003

0.15 (0.05 - 0.45), 0.0007

0.15 (0.03 - 0.69), 0.0150

Yearly personal income ≥ 50,000

Yearly personal income < 50,000

0.932

Yes

367

224

No vaccinal notice

107

0.23 (0.12 - 0.46), < 0.0001

130

0.25 (0.12 - 0.54), 0.0004

0.12 (0.04 - 0.40), 0.0006

0.17 (0.05 - 0.60), 0.0059

**Table 5.** Recognitions of Breast Cancer Patients Regarding COVID-19 Vaccination
	Unvaccinated	Vaccinated	OR (95% CI)	P-value
COVID-19: coronavirus disease 2019: OR: odds ratio; CI: confidence interval.
No.	730	214
Do you believe COVID-19 vaccination may cause special side effect to breast cancer patients?			1.17 (1.01 - 1.33)	< 0.001
I don’t know	592 (81.10%)	98 (45.79%)
No	53 (7.26%)	112 (52.34%)
Yes	85 (11.64%)	4 (1.87%)
Do you believe breast cancer patients can be inoculated with COVID-19 vaccine?			0.73 (0.57 - 0.89)	< 0.001
No	284 (38.90%)	53 (24.77%)
Depend on current treatment	189 (25.89%)	108 (50.47%)
I don’t know	246 (33.70%)	33 (15.42%)
Yes	11 (1.51%)	20 (9.35%)
Do you believe the necessity of COVID-19 vaccination in China is strong or weak?			0.40 (0.25 - 0.55)	< 0.001
Strong	580 (79.45%)	199 (92.99%)
Weak	150 (20.55%)	15 (7.01%)
Do you believe vaccination may lead to recurrence of breast cancer?			1.02 (0.86 - 1.18)	< 0.001
I don’t know	572 (78.36%)	74 (34.58%)
No	147 (20.14%)	139 (64.95%)
Yes	11 (1.51%)	1 (0.47%)
Do you believe the COVID-19 vaccine is safe?			0.74 (0.59 - 0.90)	< 0.001
Yes	355 (48.63%)	175 (81.78%)
No or I don’t know	375 (51.37%)	39 (18.22%)

Table 5. Recognitions of Breast Cancer Patients Regarding COVID-19 Vaccination

Unvaccinated

Vaccinated

OR (95% CI)

P-value

COVID-19: coronavirus disease 2019: OR: odds ratio; CI: confidence interval.

No.

730

214

Do you believe COVID-19 vaccination may cause special side effect to breast cancer patients?

1.17 (1.01 - 1.33)

< 0.001

I don’t know

592 (81.10%)

98 (45.79%)

53 (7.26%)

112 (52.34%)

Yes

85 (11.64%)

4 (1.87%)

Do you believe breast cancer patients can be inoculated with COVID-19 vaccine?

0.73 (0.57 - 0.89)

< 0.001

284 (38.90%)

53 (24.77%)

Depend on current treatment

189 (25.89%)

108 (50.47%)

I don’t know

246 (33.70%)

33 (15.42%)

Yes

11 (1.51%)

20 (9.35%)

Do you believe the necessity of COVID-19 vaccination in China is strong or weak?

0.40 (0.25 - 0.55)

< 0.001

Strong

580 (79.45%)

199 (92.99%)

Weak

150 (20.55%)

15 (7.01%)

Do you believe vaccination may lead to recurrence of breast cancer?

1.02 (0.86 - 1.18)

< 0.001

I don’t know

572 (78.36%)

74 (34.58%)

147 (20.14%)

139 (64.95%)

Yes

11 (1.51%)

1 (0.47%)

Do you believe the COVID-19 vaccine is safe?

0.74 (0.59 - 0.90)

< 0.001

Yes

355 (48.63%)

175 (81.78%)

No or I don’t know

375 (51.37%)

39 (18.22%)