COVID-19 vaccination and potential predictors for vaccination among students in Bulgarian medical universities

Figures & data

Table 1. Demographic characteristics of the respondents (n = 3050).

Variable	All respondents (n = 3050)	COVID-19 vaccinated (n = 2241)	COVID-19 non-vaccinated (n = 809)	p-value
Age, median (25th percentile; 75th percentile)	22 (20;24)	22 (21;23)	21 (21;23)	0.180*
Gender, n (%)
Male	994 (32.6)	822 (82.7)	172 (17.3)	<0.001**
Female	2056 (67.4)	1419 (69.0)	637 (31.0)
Distribution of students by language-based degree programs enrollment, n (%)
Bulgarian	2236 (73.3)	1473 (65.8)	763 (34.2)	<0.001**
English	814 (26.7)	768 (94.3)	46 (5.7)
Medical university, n (%)
Medical University of Plovdiv	1669 (54.7)	1236 (74.1)	433 (25.9)
Medical University of Sofia	477 (15.6)	402 (84.3)	75 (15.7)
Medical University of Pleven	421 (13.8)	189 (44.9)	232 (55.1)	<0.001**
Medical University of Varna	416 (13.6)	377 (90.6)	39 (9.4)
Other	67 (2.2)	30 (44.8)	37 (55.2)
Degree programs, n (%)
Medicine	1748 (57.3)	1534 (87.7)	214 (12.3)
Dental medicine	343 (11.2)	259 (75.5)	84 (24.5)
Pharmacy	248 (8.1)	155 (62.5)	93 (37.5)	<0.001**
Nursing	198 (6.5)	112 (56.6)	86 (43.4)
Midwifery	84 (2.8)	43 (51.2)	41 (48.8)
Physical therapist (FPH) ‡	83 (2.8)	18 (26.9)	49 (73.1)
Other^a	346 (11.3)	120 (32.8)	242 (67.2)
Year of study, n (%)
1st year	684 (22.4)	439 (64.2)	245 (35.8)
2nd year	610 (20.0)	398 (65.2)	212 (34.8)	<0.001**
3rd year	578 (19.0)	406 (70.2)	172 (29.8)
4th year	478 (15.7)	381 (79.7)	97 (20.3)
5th year	375 (12.3)	328 (87.5)	47 (12.5)
6th year	325 (10.7)	289 (88.9)	36 (11.1)

* Mann-Whitney test comparing vaccinated and unvaccinated students.

** z-test comparing vaccinated and unvaccinated students.

^a Other—dental technician; dietician; medical cosmetics; medical laboratory assistant; assistant pharmacist, physician assistant; X-ray laboratory technician; physical therapy, wellness and SPA (medical college); healthcare management.

Table 2. Personal vaccination behavior and general attitudes of the respondents toward vaccines.

Question	All respondents (n = 3050)	COVID-19 vaccinated (n = 2241)	COVID-19 unvaccinated (n = 809)	p-value
	Participants that responded affirmatively (yes)
Flu vaccination in the previous season (2020/2021), n (%)	487 (16.0)	431 (19.2)	56 (6.9)	<0.001
Plan to receive the flu vaccine in the current season (2021/2022), n (%)	743 (24.4)	671 (29.9)	72 (8.9)	<0.001
People receive more vaccines than needed, n (%)	561 (18.4)	262 (11.7)	299 (36.9)	<0.001
Has the responsibility to be aware of the types of vaccines and the recommendations for their administration, n (%)	2762 (90.5)	2125 (94.8)	637 (78.7)	<0.001

Table 3. Personal experience with COVID-19 and COVID-19 vaccines attitudes.

Variables	All respondents (n = 3050)	COVID-19 vaccinated (n = 2241)	COVID-19 non-vaccinated (n = 809)	p-value
COVID-19 infection history
	Participants that responded affirmatively (yes)
Recovered from a COVID-19 infection, n (%)	1340 (43.9)	856 (38.2)	484 (59.8)	<0.001
Cases of COVID-19 infection in the family, n (%)	2064 (67.7)	1489 (66.4)	575 (71.1)	0.016
Personally know someone who has had COVID-19 infection, n (%)	2949 (96.7)	2175 (97.0)	774 (95.7)	0.060
Personally know someone who has died from COVID-19, n (%)	1503 (49.3)	1160 (51.8)	343 (42.4)	<0.001
Attitudes to COVID-19 vaccines
	Participants that responded affirmatively (agree/strongly agree)
COVID-19 vaccines are important for me as a health care provider, n (%)	1918 (62.9)	1846 (82.4)	72 (8.9)	<0.001
COVID-19 vaccines should be mandatory for the general public, n (%)	1170 (38.4)	1147 (51.8)	23 (2.8)	<0.001
COVID-19 vaccines should be mandatory for the healthcare providers, n (%)	1765 (57.9)	1707 (76.2)	58 (7.2)	<0.001
I am more likely to be exposed to COVID-19 as a future healthcare provider, n (%)	2326 (76.3)	1949 (87.0)	377 (46.6)	<0.001
COVID-19 vaccination is important to decrease spread of the disease, n (%)	1988 (65.2)	1855 (82.8)	133 (16.4)	<0.001
I am worried that the COVID-19 vaccine won't be effective in preventing an illness, n (%)	1308 (42.9)	717 (32.0)	591 (73.0)	<0.001
I am worried about possible adverse events following COVID-19 vaccination, n (%)	1429 (46.8)	718 (32.0)	711 (88.1)	<0.001
I have confidence in the information that I received on the COVID-19 vaccine from public health experts, n (%)	1580 (51.8)	1496(66.7)	84 (10.4)	<0.001
COVID-19 vaccines were developed too quickly and this makes them dangerous, n (%)	879 (28.8)	324 (14.4)	555 (68.6)	<0.001
COVID-19 vaccines are part of a conspiracy plan to reduce the human population, n (%)	457 (15.0)	163 (7.2)	294 (36.3)	<0.001
Main reasons for vaccine hesitancy, n (%)
Fear of adverse events	1019 (33.4)	282 (12.6)	737 (91.1)	<0.001
Doubts about vaccine safety	1001 (32.8)	366 (16.3)	653 (80.7)
Main source of information about the COVID-19 vaccines, n (%)
Official sources (WHO, CDC, MH)	2530 (82.9)	2008 (89.6)	522 (64.6)
University teachers	1223 (41.0)	942 (42.0)	281 (34.8)	<0.001
Friends and relatives	268 (8.8)	145 (6.5)	123 (15.2)
Internet/social media	217 (7.1)	133 (5.9)	84 (10.4)

Table 4. Binominal logistic regression model for COVID-19 vaccination.

Model	Unstandardized coefficients		Wald	df	Sig.	Exp (B)	95% confidence interval for B
	B	Std. error					Lower bound	Upper bound
(Constant)
Language of education
English (baseline)
Bulgarian	−0.850	0.238	12.736	1	0.000	0.428	0.268	0.682
University programs
Medicine (baseline)
Dental medicine	−0.134	0.227	0.347	1	0.556	0.875	0.561	1.364
Pharmacy	−0.353	0.231	2.333	1	0.127	0.702	0.446	1.105
Nursing	−0.453	0.247	3.369	1	0.066	0.636	0.392	1.031
Midwifery	−0.606	0.332	3.329	1	0.068	0.545	0.284	1.046
Health care management	−1.187	0.569	4.354	1	0.037	0.305	0.100	0.930
Rehabilitation, wellness and SPA	−2.095	1.061	3.900	1	0.048	0.123	0.015	0.984
Public health inspector	−1.145	0.596	3.695	1	0.055	0.318	0.099	1.023
X-ray laboratory technician	0.472	0.566	0.694	1	0.405	1.603	0.528	4.862
Assistant pharmacist	−1.793	0.418	18.432	1	0.000	0.166	0.073	0.377
Dental technician	−1.728	0.621	7.737	1	0.005	0.178	0.053	0.600
Physical therapist	−1.240	0.418	8.776	1	0.003	0.289	0.127	0.657
Medical cosmetics	−1.078	0.458	5.527	1	0.019	0.340	0.139	0.836
Medical laboratory assistant	−1.203	0.517	5.410	1	0.020	0.300	0.109	0.827
Physician assistant	0.381	0.637	0.358	1	0.550	1.464	0.420	5.108
Responsibility as a future HCW to be familiar with the types of vaccines
Strongly agree (baseline)
Strongly disagree	0.729	0.379	3.701	1	0.054	2.074	0.986	4.359
Disagree	0.743	0.420	3.129	1	0.077	2.103	0.923	4.792
Neither agree nor disagree	0.542	0.242	5.017	1	0.025	1.719	1.070	2.763
Agree	0.365	0.182	4.033	1	0.045	1.440	1.009	2.056
Vaccination against COVID-19 is important
Strongly agree (baseline)
Strongly disagree	−3.431	0.352	95.218	1	0.000	0.032	0.016	0.064
Disagree	−2.734	0.342	63.920	1	0.000	0.065	0.033	0.127
Neither agree nor disagree	−2.090	0.299	48.833	1	0.000	0.124	0.069	0.222
Agree	−1.263	0.298	17.983	1	0.000	0.283	0.158	0.507
Vaccines against COVID-19 should be mandatory for medical personnel
Strongly agree (baseline)
Strongly disagree	−1.479	0.290	25.958	1	0.000	0.228	0.129	0.403
Disagree	−1.206	0.300	16.136	1	0.000	0.299	0.166	0.539
Neither agree nor disagree	−0.540	0.281	3.691	1	0.055	0.582	0.336	1.011
Agree	0.011	0.303	.001	1	0.971	1.011	0.559	1.829
Concerns about possible side effects from the administration of the COVID-19 vaccine
Strongly agree (baseline)
Strongly disagree	0.957	0.361	7.011	1	0.008	2.603	1.282	5.283
Disagree	0.672	0.315	4.538	1	0.033	1.958	1.055	3.634
Neither agree nor disagree	0.487	0.232	4.422	1	0.035	1.628	1.034	2.563
Agree	0.094	0.187	0.255	1	0.613	1.099	0.762	1.585
Vaccines are part of a conspiracy plan to reduce the population, and the virus was artificially created for this purpose
Strongly disagree (baseline)
Disagree	−0.149	0.220	0.458	1	0.499	0.862	0.560	1.326
Neither agree nor disagree	−0.141	0.194	0.533	1	0.466	0.868	0.594	1.269
Agree	−0.206	0.278	0.550	1	0.458	0.813	0.471	1.404
Strongly agree	0.601	0.240	6.286	1	0.012	1.823	1.140	2.916
Access to sufficient information to inform COVID-19 vaccination
Yes (baseline)
No	−0.552	0.181	9.277	1	0.002	0.576	0.404	0.821
Availability of public awareness and education campaigns about effectiveness and safety of COVID-19 vaccines
Yes (baseline)
No	−0.454	0.213	4.543	1	0.033	0.635	0.419	0.964
Access to sufficient information about COVID-19 vaccines during university education
Yes (baseline)
No	0.430	0.180	5.740	1	0.017	1.537	1.081	2.186
COVID-19 diagnosis
Yes (baseline)
No	0.884	0.141	39.574	1	0.000	2.421	1.838	3.188
Has received all vaccines according to the mandatory immunization schedule
I do not know (baseline)
No	−2.383	0.438	29.629	1	0.000	0.092	0.039	0.218
Yes	0.137	0.294	0.218	1	0.641	1.147	0.645	2.040

Data availability

The data that support the findings of this study are available from the corresponding author, V.R., upon reasonable request.