Analysis of past vaccination campaigns
Following the season 2017/18, a significant increase (p<0.001) in overall VC was observed in the season of 2018/19, yielding a VC of 16% (2,289/14,224) in comparison to a VC of 11% (1,514/14,272) in the prior season, which corresponds to a 1.5-fold increase. Concerning professional fields, a significant increase in VC occurred in all categories except for subsidiary company employees. Highest relative increase was observed in administration staff (22% (182/819) to 52% (420/809), 2.4-fold increase, p<0.001), followed by functional staff (8% (260/3,257) to 15% (472/3,187), 1.9-fold increase, p<0.001) and nurses (13% (225/1,696) to 21% (354/1,668), 1.6-fold increase, p<0.001). Among the different professional fields, VC was highest in physicians in the season of 2017/18, further increasing from 38% (538/1,422) to 52% (714/1,383) in 2018/19 (1.4-fold increase, p<0.001). In the season 2018/19 both physicians and administration staff yielded highest VC reaching 52% (Fig. 2, Tab. 1).
Between the seasons of 2018/19 and 2019/20 a significant increase (p=0.040), albeit only corresponding to a 1.1-fold increase, in VC occurred as well. The overall VC of 16% (2,289/14,224) in 2018/19 increased to 17% (2,465/14,505) in the season of 2019/20. Keeping in mind that documentation of professional field of vaccinees was not available for 4% in 2018/19 and for 11% in 2019/20, a decrease in VC per professional field was observed across all fields. Notably, in 2019/20, VC per professional field was highest in administration staff, closely followed by physicians. VC did not exceed 18% in nurses, 15% in functional staff and was lowest in subsidiary company employees (Fig. 2, Tab. 1).
Demographics of HCW vaccinated over the course of the three seasons between 2017/18 and 2019/20 are shown in Table 2.
Table 1. Vaccination coverage per professional field between 2017/18 and 2020/21
|
2017/18
|
2018/19
|
2019/20
|
2020/21
|
|
VC in % (Vacc. / employees)
|
VC in % (Vacc. / employees)
|
p-value (2017/18 vs 2018/19)
|
Relative change (2017/18 vs. 2018/19)
|
VC in % (Vacc. / employees)
|
p-value (2017/18 vs 2018/19)
|
Relative change (2018/19 vs. 2019/20)
|
VC in % (Vacc. / employees)
|
p-value (2017/18 vs 2018/19)
|
Relative change (2019/20 vs. 2020/21)
|
Administration staff
|
22 (182/819)
|
52 (420/809)
|
<0.001
|
+134%
|
46 (387/836)
|
0.023
|
-11%
|
62 (542/872)
|
<0.001
|
+34%
|
Functional service
|
8 (260/3257)
|
15 (472/3187)
|
<0.001
|
+86%
|
15 (463/3152)
|
0.892
|
-1%
|
35 (1080/3072)
|
<0.001
|
+139%
|
Nursing staff
|
13 (225/1696)
|
21 (354/1668)
|
<0.001
|
+60%
|
18 (340/1920)
|
0.008
|
-17%
|
48 (1060/2215)
|
<0.001
|
+170%
|
Physicians
|
38 (538/1422)
|
52 (714/1383)
|
<0.001
|
+36%
|
41 (599/1457)
|
<0.001
|
-20%
|
81 (1215/1505)
|
<0.001
|
+96%
|
Research personnel
|
8 (76/914)
|
11 (101/911)
|
0.045
|
+33%
|
9 (82/915)
|
0.131
|
-19%
|
69 (675/981)
|
<0.001
|
+668%
|
Students/Trainees/Interns
|
2 (76 /4468)
|
n.a.
|
-
|
n.a.
|
5 (235/4421)
|
-
|
n.a.
|
22 (1023/4717)
|
<0.001
|
+308%
|
Subsidiary company emp.
|
8 (139/1696)
|
8 (133/1759)
|
0.489
|
-8%
|
5 (94/1804)
|
0.004
|
-31%
|
16 (295/1897)
|
<0.001
|
+198%
|
Other
|
15
|
n.a.
|
-
|
-
|
n.a.
|
-
|
-
|
158
|
-
|
-
|
n. a.
|
3
|
95
|
-
|
-
|
265
|
-
|
-
|
-
|
-
|
-
|
VC, vaccination coverage; Vacc., vaccinations; n.a., not available
Table showing the VC per professional field of the seasons 2017/18 to 2020/21 including p-value of change in VC per professional field between prior and the respective following season calculated using chi-squared test
Table 2. Demographic data of vaccinees during the seasons 2017/18 – 2020/21
|
Category
|
2017/18
|
%
|
2018/19
|
%
|
p-value (2017/18 vs 2018/19)
|
2019/20
|
%
|
p-value (2018/19 vs 2019/20)
|
2020/21
|
%
|
p-value (2019/20 vs. 2020/21)
|
Vaccinated / Employees
|
-
|
1514/14272
|
11%
|
2289/14224
|
16%
|
<0.001
|
2465/
14505
|
17%
|
0.040
|
6048/15290
|
40%
|
<0.001
|
Age (years) distribution among vaccinated
|
< 20
|
14
|
1%
|
38
|
2%
|
0.056
|
41
|
2%
|
0.993
|
55
|
1%
|
0.003
|
20 - 29
|
376
|
25%
|
656
|
29%
|
0.009
|
777
|
32%
|
0.032
|
1236
|
20%
|
<0.001
|
30 - 39
|
436
|
29%
|
580
|
25%
|
0.018
|
643
|
26%
|
0.556
|
1129
|
19%
|
<0.001
|
40 - 49
|
293
|
19%
|
429
|
19%
|
0.638
|
421
|
17%
|
0.135
|
687
|
11%
|
<0.001
|
50 - 59
|
295
|
19%
|
420
|
18%
|
0.380
|
390
|
16%
|
0.021
|
701
|
12%
|
<0.001
|
≥ 60
|
100
|
7%
|
165
|
7%
|
0.474
|
193
|
8%
|
0.417
|
263
|
4%
|
<0.001
|
n. a.
|
0
|
-
|
1
|
0%
|
-
|
0
|
-
|
|
1977
|
33%
|
<0.001
|
Sex distribution among vaccinated
|
Female
|
904
|
60%
|
1380
|
60%
|
0.721
|
1501
|
61%
|
0.670
|
2598
|
43%
|
<0.001
|
Male
|
605
|
40%
|
906
|
40%
|
0.815
|
963
|
39%
|
0.717
|
1473
|
24%
|
<0.001
|
n. a.
|
5
|
0%
|
3
|
0%
|
-
|
1
|
0%
|
-
|
1977
|
33%
|
<0.001
|
Professional field distribution among vaccinated
|
Administration staff
|
182
|
12%
|
420
|
18%
|
<0.001
|
387
|
16%
|
0.015
|
542
|
9%
|
<0.001
|
Functional service
|
260
|
17%
|
472
|
21%
|
0.008
|
463
|
19%
|
0.111
|
1080
|
18%
|
0.315
|
Nursing staff
|
225
|
15%
|
354
|
15%
|
0.612
|
340
|
14%
|
0.103
|
1060
|
18%
|
<0.001
|
Physicians
|
538
|
36%
|
714
|
31%
|
0.005
|
599
|
24%
|
<0.001
|
1215
|
20%
|
<0.001
|
Research personnel
|
76
|
5%
|
101
|
4%
|
0.384
|
82
|
3%
|
0.052
|
675
|
11%
|
<0.001
|
Students/Trainees/Interns
|
76
|
5%
|
n. a.
|
n. a.
|
-
|
235
|
10%
|
-
|
1023
|
17%
|
<0.001
|
Subsidiary company employees
|
139
|
9%
|
133
|
6%
|
<0.001
|
94
|
4%
|
0.001
|
295
|
5%
|
0.033
|
Other
|
15
|
1%
|
n. a.
|
n. a.
|
-
|
n. a.
|
n. a.
|
-
|
158
|
3%
|
-
|
n. a.
|
3
|
0%
|
95
|
4%
|
-
|
265
|
11%
|
-
|
-
|
-
|
-
|
n.a., not available
Table showing the demographic data of vaccinees during the seasons of 2017/18 to 2019/20. The p-value for the change in distribution among vaccinees in different categories (age, sex, and professional field) between the previous and the following season was evaluated using the chi-squared test. The category “other” applied whenever the professional field was known but did not fit into the given categories.
Analysis of the 2020/21 campaign
The intensified influenza vaccination campaign 2020/21 led to a significant increase in overall VC from 17% (2,465/14,505) in the previous season to 40% (6,048/15,290) (2.4-fold increase; p<0.001) in 2020/21 (Fig. 2). Excluding medical students, the overall VC increased (p<0.001) from 22% (2,230/10,084) in 2019/20 to 48% (5,025/10,573) in 2020/21 (2.2-fold increase).
The increase in VC within each professional field was significant across all professional fields (Table 1). Yielded VC was highest in physicians with 81% (1,215/1,505, 2-fold increase), followed by research personnel with 69% (675/981, 7.7-fold increase), administration staff with 62% (542/872, 1.3-fold increase), nurses with 48% (1,060/2,215, 2.7-fold increase), functional staff with 35% (1,080/3,072, 2.3-fold increase), medical students/trainees/interns with 22% (1,023/4,717, 4.4-fold increase) and subsidiary company employees with 16% (295/1,897, 3.2-fold increase) (Fig. 2, Tab. 1).
Out of all vaccinees, 4,071 (67%) were vaccinated by the appointed MVT (OSV, CVS and MVE) while 1,977 (33%) HCW received the flu vaccine by the OH. Concerning vaccination sites, 33% received vaccination at the OH, 31% were vaccinated on-site, 30% were vaccinated at the CVS and 6% during MVE (Fig. 3). Out of the 4,071 HCW vaccinated by the MVT, 2,598 (64%) were female and 1,473 (36%) were male, in comparison to the overall sex distribution of 69% female and 31% male employees at UHC. Further demographic information on HCW vaccinated can be found are presented in Table 2.
The demographic data of MVT vaccinees was further analysed regarding the three vaccination sites provided by the MVT. Among those vaccinated by the MVT, the age distribution between OSV and CVS was similar with a median age of 38 (IQR: 29 – 51) at the CVS in comparison to the median age of 37 (IQR: 29 – 49) of OSV vaccinees. Those vaccinated during MVE (almost exclusively medical students) were generally younger (median: 22, IQR: 21 – 24). Regarding sex, 46% of female vaccinees were vaccinated at the CVS, 45% on-site and 9% at the MVE, whereas male vaccinees mainly received vaccination on-site (48%), followed by vaccination at the CVS (42%) and MVE (10%). Physicians and nursing staff both predominantly received vaccination at the CVS (59% and 57%, respectively) in comparison to OSV (41% and 43%, respectively), while research personnel and administration staff predominantly chose OSV (89% and 57%, respectively) compared to vaccination at the CVS (12% and 43%, respectively) (Tab. 3).
The campaign of 2020/21 kicked-off on September 7th, as soon as the vaccine shipment arrived. During the first few days the MVT was at the CVS daily during lunchtime and HCW could drop in spontaneously. The campaign was officially announced via e-mail to all HCW by the hospital board on September 10th, simultaneously promotional material (posters, pamphlets) was spread across the hospital campus. Almost 3,000 HCW were vaccinated by the MVT by the time a vaccine shortage hit on October 13th which lasted for almost a month. During this time the opening hours at the CVS were shortened. To inform on the arrival of new vaccine supplies, a second e-mail to all HCW was sent out on November 11th. In the same week a promotional flash mob of distributing saddle bike covers depicting the campaign logo on bicycles across campus took place. During end of November and beginning of December four MVE for medical students were conducted by the MVT. Two weeks before the end of the intensified campaign a third “last call” reminder e-mail was sent out to all HCW. Of note, when comparing Tuesdays (main weekly CVS day) before and after, all three e-mails to HCW by the hospital board led to an increase of vaccinations per day. The milestone of 4,000 vaccinations by the MVT was reached on December 10th. Following the end of the intensified campaign on December 18th, HCW could still receive influenza vaccination at the OH during opening hours in the following weeks (Fig. 4).
Table 3. Demographic data of MVT vaccinees outlined per vaccination site
VS
|
Age
|
Sex
|
Professional fields
|
Median (IQR)
|
Female (% per site)
|
Male (% per site)
|
Administration staff (% per site)
|
Functional service (% per site)
|
Nursing staff
(% per site)
|
Physicians (% per site)
|
Research personnel (% per site)
|
Students / Trainees / Interns (% per site)
|
Subsidiary company emp. (% per site)
|
Other (% per site)
|
CVS
|
38 (29 – 51)
|
1203 (46%)
|
625 (42%)
|
115 (43%)
|
473 (52%)
|
367 (57%)
|
511 (59%)
|
53 (12%)
|
207 (30%)
|
81 (40%)
|
19 (95%)
|
OSV
|
37 (29 – 49)
|
1166 (45%)
|
706 (48%)
|
154 (57%)
|
434 (48%)
|
272 (43%)
|
362 (41%)
|
408 (89%)
|
119 (17%)
|
122 (60%)
|
1 (5%)
|
MVE
|
22 (21 – 24)
|
229 (9%)
|
142 (10%)
|
0 (0%)
|
0 (0%)
|
0 (0%)
|
0 (0%)
|
0 (0%)
|
371 (53%)
|
0 (0%)
|
0 (0%)
|
VS, vaccination site; CVS, central vaccination site; OSV, on-site vaccination; MVE, mass vaccination event
Table showing the demographic data of MVT vaccinees including age, sex, and professional field per vaccination site.
Analysis of the survey following the campaign 2020/21
A response rate of 22% (3,327/15,290) was observed in the 2020/21 influenza vaccination campaign survey, which was conducted from February 17th to March 3rd, 2021. Out of all participants, 73% (2,413/3,327) reported having received influenza vaccination during the 2020/21 season. Out of the reportedly vaccinated employees, 13% (318/2,413) stated having received the vaccination externally (e.g., at their primary care physician). Out of all vaccinated respondents, the COVID-19 pandemic contributed to a positive vaccination decision for 30% (720/2,413) of those vaccinated. For 40% (968/2,413) of those reportedly vaccinated, the intensified 2020/2021 vaccination campaign increased vaccination readiness. For 29% (706/2,413) the 2020/21 season’s vaccination was their first influenza vaccination ever or their first influenza vaccination in over 10 years. Out of these first timers, 60% (421/706) stated the intensified campaign had a positive impact on their decision to receive vaccination. Additionally, 72% (510/706) of first timers stated the COVID-19 pandemic positively influenced their decision to receive vaccination. Concerning the response per professional field, for 31% (116/379) of vaccinated nursing staff, the 2020/21 influenza vaccination was reportedly their first flu vaccination ever (or in over 10 years). Out of these first timers among nursing staff, 78% (90/116) stated the COVID-19 pandemic and 53% (61/116) stated the intensified campaign positively influenced their decision to receive flu vaccination. For 43% (50/116), both the COVID-19 pandemic and the intensified campaign contributed positively to their vaccination decision (Tab. 4).
The optionally written feedback in the survey repeatedly highlighted the options to receive vaccination spontaneously at the CVS on the way to or from lunch as well as the option to receive OSV. A few comments pointed towards misconceptions, such as not wanting to receive vaccination due to pregnancy and not wanting to receive a live vaccine. Furthermore, reasons for declining vaccination were expressed, such as wanting to be ready for the COVID-19 vaccination at any given moment or believing flu vaccination to be unnecessary due to COVID-19 policies.
Table 4. Survey results on the 2020/21 campaign outlined by professional fields
|
Overall
N = 3327 (100%)
|
Admin. staff
N = 581 (17%)
|
Functional Services
N = 300 (9%)
|
Physicians
N 412 = (12%)
|
Research personnel
N = 449 (14%)
|
Students/
Trainees/
Interns
N = 588 (18%)
|
Subsidiary Company Employees
N = 190 (6%)
|
Other
N = 211 (6%)
|
N
|
[%]
|
N
|
[%]
|
N
|
[%]
|
N
|
[%]
|
N
|
[%]
|
N
|
[%]
|
N
|
[%]
|
N
|
[%]
|
Vaccinated
|
2413
|
73
|
395
|
68
|
214
|
71
|
382
|
93
|
336
|
75
|
430
|
73
|
134
|
71
|
143
|
68
|
Vaccination site
|
OSV
|
729
|
30
|
138
|
35
|
84
|
39
|
107
|
28
|
175
|
52
|
36
|
8
|
53
|
40
|
47
|
33
|
CVS
|
682
|
28
|
136
|
34
|
60
|
28
|
144
|
38
|
75
|
22
|
57
|
13
|
42
|
31
|
38
|
27
|
OH
|
558
|
23
|
77
|
19
|
49
|
23
|
96
|
26
|
60
|
18
|
92
|
21
|
26
|
19
|
39
|
27
|
Ex
|
318
|
13
|
44
|
11
|
21
|
10
|
34
|
9
|
26
|
8
|
122
|
28
|
13
|
10
|
19
|
13
|
MVE
|
126
|
5
|
0
|
0
|
0
|
0
|
1
|
0
|
0
|
0
|
123
|
29
|
0
|
0
|
0
|
0
|
First timers1 overall
|
706
|
29
|
124
|
31
|
68
|
32
|
41
|
11
|
126
|
38
|
134
|
31
|
49
|
37
|
48
|
34
|
COVID-192 overall
|
720
|
30
|
139
|
35
|
82
|
38
|
61
|
16
|
121
|
36
|
104
|
24
|
46
|
34
|
42
|
29
|
COVID-192 among first timers1
|
510
|
72
|
98
|
79
|
60
|
88
|
25
|
61
|
91
|
72
|
75
|
56
|
35
|
71
|
36
|
75
|
Campaign3 overall
|
968
|
40
|
166
|
42
|
71
|
33
|
126
|
33
|
147
|
44
|
202
|
47
|
62
|
46
|
60
|
42
|
Campaign3 among first timers1
|
421
|
60
|
76
|
61
|
36
|
53
|
24
|
59
|
83
|
66
|
82
|
61
|
30
|
61
|
29
|
60
|
N, number; MVT, mobile vaccination team; OSV, on-site vaccination; CVS, central vaccination site; OH, occupational health; Ex, externally (e.g., primary physician’s office); MVE, mass vaccination event; 1first time influenza vaccination ever or in over 10 years; 2COVID-19 positively influenced vaccination decision; 3intensified vaccination campaign positively influenced vaccination decision
Table showing the results of the conducted survey on the intensified influenza vaccination campaign 2020/21. The number and percentage of vaccinations as reported are shown for each professional field. Furthermore, the vaccination site per professional field, whether this year’s vaccination was their reportedly first (or first time in over 10 years) vaccination, whether the COVID-19 pandemic positively influenced their decision to receive the vaccine and whether the intensified campaign increased their vaccination readiness in the season of 2020/21 per professional field is outlined