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Int. J. Environ. Res. Public Health 2021, 18, 5272. https://doi.org/10.3390/ijerph18105272 www.mdpi.com/journal/ijerph
Article
Willingness to Be Vaccinated against COVID-19 in Spain
before the Start of Vaccination: A Cross-Sectional Study
Noelia Rodríguez-Blanco
1,2,
*, Sergio Montero-Navarro
3
, José M. Botella-Rico
3
, Antonio J. Felipe-Gómez
2
,
Jesús Sánchez-Más
2
and José Tuells
4
1
Department of Obstetrics and Gynaecology, Marina Baixa University Hospital,
Av. Alcalde En Jaume Botella Mayor, 7, 03570 Villajoyosa, Spain
2
Biomedical Sciences Department, Health Sciences Faculty, CEU-Cardenal Herrera University,
CEU Universities, Plaza Reyes Católicos, 19, 03204 Elche, Spain;
antonio.felipe@alumnos.uchceu.es (A.J.F.-G.); jesus.sanchez@uchceu.es (J.S.-M.)
3
Physical Therapy Department, Health Sciences Faculty, CEU-Cardenal Herrera University,
CEU Universities, Plaza Reyes Católicos, 19, 03204 Elche, Spain;
sergio.montero@uchceu.es (S.M.-N.); jmbotella@uchceu.es (J.M.B.-R.)
4
Department of Community Nursing, Preventive Medicine and Public Health and History of Science,
University of Alicante, San Vicente del Raspeig, 03690 Alicante, Spain; tuells@ua.es
* Correspondence: noelia.rodriguez@uchceu.es; Tel.: +34-965426486
Abstract: Vaccine hesitancy has increased in the past few years, influenced by the socio-cultural
differences, political populism, or concerns related to the effectiveness and safety of some vaccines,
resulting a feeling of distrust. This feeling can become a barrier against the achievement of the im-
munity necessary to stop the expansion of COVID-19. The aim of this study was to evaluate the
acceptance of the vaccine against COVID-19 in Spain, as well as to identify the factors that have an
influence on the concerns and attitudes of people against accepting the vaccine in the months prior
to the start of vaccination on December 2020. An online questionnaire was created to obtain infor-
mation about (1) sociodemographic characteristics; (2) concerns and sources of information about
vaccines; and (3) attitudes about vaccination and state of health. A multivariate logistic regression
was performed to identify the influencing factors. Of the 2501 participants, 1207 (48.3%) would ac-
cept the COVID-19 vaccine, 623 (24.9%) were hesitant, and 671 (26.8%) would reject it. The logistic
regression showed that being male, older than 60, married, retired, with a high level of education,
or with a leftist political inclination, could increase the probability of accepting the COVID-19 vac-
cine. Disinformation and the lack of political consensus were the main sources of distrust. The pa-
tients with hypertension, immunodepression, hypercholesterolemia, or respiratory disease, or were
overweight, showed a greater acceptance to the vaccine, while those with cancer took the longest to
accept it. A low acceptance of the vaccine against COVID-19 was observed among the Spanish pop-
ulation in the phase prior to its availability, and the main fears of the population were identified. It
is necessary to offer correct and transparent information about these vaccines to reduce the concerns
and increase the trust of the population, to thereby guarantee the success of the vaccination cam-
paigns.
Keywords: vaccines; COVID-19; SARS-CoV-2; vaccine acceptance; vaccine hesitancy; vaccination
campaign; immunization program
1. Introduction
Spain is one of the countries which has been greatly affected by the SARS-CoV-2 vi-
rus, with more than 74,064 deaths and more than 3,241,345 confirmed cases until now [1].
Vaccination against COVID-19 is the best strategy for mitigating the expansion of the dis-
ease; thus, achieving a reasonable herd immunity is necessary. In Spain, the vaccination
campaign began on 27th December 2020, in unison with the 27 EU countries. Although
Citation: Rodríguez-Blanco, N.;
Montero-Navarro, S.; Botella-Rico,
J
.M.; Felipe-Gómez, A.J.;
Sánchez-Más, J.; Tuells, J.
Willingness to Be Vaccinated against
COVID-19 in Spain before the Start
of Vaccination: A Cross-Sectional
Study. Int. J. Environ. Res. Public
Health 2021, 18, 5272. https://doi.org/
10.3390/ijerph18105272
Academic Editor: Paul B.
Tchounwou
Received: 1 April 2021
Accepted: 5 May 2021
Published: 15 May 2021
Publisher’s Note: MDPI stays neu-
tral with regard to jurisdictional
claims in published maps and institu-
tional affiliations.
Copyright: © 2021 by the authors. Li-
censee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and con-
ditions of the Creative Commons At-
tribution (CC BY) license (http://crea-
tivecommons.org/licenses/by/4.0/).
Int. J. Environ. Res. Public Health 2021, 18, 5272 2 of 12
these date were symbolic, vaccination begun immediately with a scheme which priori-
tized certain population groups: individuals living in elderly homes, the workers in these
centers, frontline health workers, and dependents [2]. However, there is a latent risk that
feelings of rejection could emerge that are associated with the secondary effects from the
vaccine, a low literacy related to health, or a low perception of risk of becoming infected
[3,4]. Vaccine hesitancy has steadily increased since 2014 [5], which could become a severe
problem in the fight against COVID-19, as was already observed during the 2009 H1N1
Influenza A Pandemic [6–8]. At present, socio-cultural differences, the increase in political
populism, and concerns about the effectiveness or safety of these new vaccines have been
observed, as well as an excess of false news in the media and social networks that have
created mistrust in the population [3,9–11].
As recommended by the WHO, it is very important to periodically evaluate the atti-
tude and pre-disposition of the population associated to the vaccine against COVID-19, to
implement measures that could guide the vaccination campaign and increase the ac-
ceptance and demand for vaccination [12]. It has been said that the end of the pandemic
could be glimpsed when 70% of the world’s population, approximately 5.6 billion people,
is immunized, and to achieve this objective, solid rates of vaccination in every country are
needed [13,14]; however, this has been questioned recently [15].
The studies published prior to the start of the vaccination campaign have shown dif-
ferent vaccine hesitancy results depending on the date consulted, from 9–12% in China,
14–28% in the UK, 22.4% in Spain, 25–33% in the USA, to 41% and 45% in France and
Russia, respectively [16–20]. It is known that the acceptance of a vaccine by the same pop-
ulation group could vary as the start of vaccination nears, and that it greatly depends on
the communication strategy utilized by the institutions. In this sense, the Spanish Govern-
ment insisted on the importance of a good communication strategy and equal access to it
before the arrival of the vaccine to Spain [21].
The aim of the study was to find out the percentage of acceptance of the vaccines for
the prevention of the COVID-19 disease in the Spanish population just before the start of
the vaccination campaign, as well as to identify the factors that have an influence on the
concerns and attitudes of the people for accepting them.
2. Materials and Methods
2.1. Design, Population, and Sample
A cross-sectional descriptive study was conducted, starting on 26th November 2020,
and ending on 26th December, coinciding with the day prior to the start of vaccination in
Spain. The study used an electronic questionnaire and included all those older than 18
who resided in Spain, and who utilized social networks such as WhatsApp, Facebook, and
Instagram, and smartphones. The Spanish population aged 18 or older, numbering
40,631,764 individuals, as estimated by the National Statistics Institute (INE) as of 1 July
2020, was used as the reference population [22]. The calculation of the sample size was
385, with a level of confidence of 95%, and a margin of error of 5% [23].
2.2. Data-Collection Tool
A questionnaire designed ad hoc, based on previous studies [24,25], was utilized as
the data-collection instrument, and a pilot study was conducted with a group of 50 health
sciences university students (25 men and 25 women), who were not taken into account for
this analysis. This pilot study allowed us to collect the impressions of those polled, which
were afterwards evaluated by a group of experts to redesign the questionnaire and guar-
antee the validity of the different items. The final questionnaire was composed of 23 ques-
tions, which included the following: (1) sociodemographic characteristics (age, sex, mari-
tal status, education, employment, economic status, political inclination, and religion); (2)
concerns and sources of information about vaccines; and (3) attitudes towards vaccination
and the current state of health. All the questions were close-ended. The voluntary consent,
Int. J. Environ. Res. Public Health 2021, 18, 5272 3 of 12
objectives of the study, the code of acceptance from the ethics committee, and the esti-
mated length of time needed for completing the questionnaire were included on the ques-
tionnaire heading.
2.3. The Dependent Variable
The dependent variable was the acceptance of the COVID-19 vaccine. The individu-
als who answered “yes” to the question “When the Covid-19 vaccine is available, are you
willing to receive it as soon as possible?” were classified into the acceptance group, and
those who answered “no” were assigned to the rejection group, while those who an-
swered “I don’t know” were assigned to the hesitant group. A total of 2621 questionnaires
were obtained, with a final sample of 2501 due to the exclusion of 120 questionnaires in
which the first question had not been answered.
2.4. Methods of Analysis
The mean ± standard deviation was utilized for the quantitative variables, and fre-
quency tables for the qualitative data. The Chi-square test was utilized to investigate the
relationships between the categorical variables. The factors associated to the willingness
to receive the vaccine were identified through the use a logistic regression analysis. A
multivariate logistic regression was performed between the three groups (acceptance
group vs. rejection group or hesitant group) to identify the factors which had an influence
of vaccine acceptance, with the odds ratio (OR) probability and a confidence interval (CI)
of 95% calculated. The likelihood was calculated with Wald Chi-square test, and the good-
ness-of-fit was tested by Pearson’s test. The statistical analysis was performed with the
IBM SPSS Statistics para Windows, version 24.0.
2.5. Ethical Considerations
The study was conducted in accordance to the principles from the Declaration of Hel-
sinki on human clinical trials, and the research proposal was approved in November 2020,
by the Ethics Committee from the CEU Cardenal-Herrera University (CEI20/094).
3. Results
3.1. Population Description
The detailed characteristics of the participants, and the statistical analysis of the ex-
planatory variables of the decision to accept the vaccine are found in Table 1. Of the 2501
participants who answered the main study question “When the Covid-19 vaccine is avail-
able, are you willing to receive it as soon as possible?” 48.3% (1207) answered affirma-
tively. Moreover, 51.7% of the participants rejected (671) or were hesitant (623) about ac-
cepting the COVID-19 vaccine. The mean age of the participants was 40.2 ± 13.6 (18–97),
and 71.8% were women (Table 1).
Table 1. Sociodemographic characteristics of the participants and multivariate logistic regression analyses showing factors
associated with acceptance of a COVID-19 vaccine in Spain.
Variable (n) Accept Rejection Hesitation
n (%) n (%) OR (95% CI) p-Value n (%) OR (95% CI) p-Value
Gender (2494)
Male (R) 396 (55.9) 164 (23.2) 1 <0.001 148 (23.9) 1 0.001
Female 809 (45.3) 506 (28.3) 1.51 (1.22–1.87) 471 (26.4) 1.55 (1.25–1.94)
Civil status (2494)
Couple (R) 802 (51.5) 388 (24.9) 1 0.001 366 (23.5) 1 0.02
Single 316 (43.9) 217 (30.1) 1.42 (1.15–1.75) 0.043 187 (26.0) 1.30 (1.04–1.61) 0.011
Divorced 88 (41.5) 61 (28.8) 1.43 (1.01–2.03) 63 (29.7) 1.57 (1.11–2.22)
Age group (2412)
18–29 (R) 289 (45.5) 182 (28.7) 1 1 164 (25.8) 1 1
Int. J. Environ. Res. Public Health 2021, 18, 5272 4 of 12
30–39 206 (44.9) 134 (29.2) 1.03 (0.78–1.38) 0.824 119 (25.9) 1.02(0.76–1.37) 0.906
40–49 368 (49.5) 200 (30.7) 0.86 (0.67–1.11) 0.254 176 (23.7) 0.84 (0.65–1.10) 0.202
50–59 178 (47.7) 99 (15.2) 0.88 (0.65–1.20) 0.429 96 (25.7) 0.95 (0.67–1.30) 0.750
>60 119 (59.2) 36 (17.9) 0.48 (0.32–0.73) 0.001 46 (7.7) 0.68 (0.46–1.00) 0.054
Employment (2461)
Worker (R) 909 (50.2) 486 (26.8) 1 1 416 (23.0) 1 1
Unemployed 30 (39.5) 20 (26.3) 1.25 (0.70–2.22) 0.453 26 (34.2) 1.89 (1.11–3.24) 0.020
Retired 71 (55.5) 20 (15.6) 0.53 (0.32–0.88) 0.013 37 (28.9) 1.14 (0.75–1.72) 0.539
Student 186 (41.7) 131 (29.4) 1.32 (1.03–1.69) 0.03 129 (28.9) 1.51 (1.18–1.95) 0.001
Type of work (1811)
Health (R) 363 (52.0) 179 (25.6) 1 1 156 (22.3) 1 1
Humanities 130 (508) 71 (27.7) 1.11 (0.79–1.56) 0.556 55 (51.5) 0.98 (0.68–1.42) 0.933
Social 161 (45.9) 106 (30.2) 1.34 (0.99–1.81) 0.062 84 (23.9) 1.20 (0.88–1.68) 0.240
Services 197 (49.0) 104 (25.9) 1.07 (0.80–1.44) 0.653 101 (25.1) 1.19 (0.88–1.62) 0.256
Others 58 (55.8) 26 (25.0) 0.91 (0.55–1.49) 0.706 20 (19.2) 0.80 (0.47–1.38) 0.426
Level of study (2483)
University (R) 761 (51.7) 374 (25.4) 1 1 336 (22.8) 1 1
Vocational training 135 (38.2) 130 (36.8) 1.96 (1.50–2.57) <0.001 88 (24.9) 1.48 (1.10–2.00) 0.010
A-level degree 156 (43.6) 94 (26.3) 1.23 (0.92–0.162) 0.160 108 (30.2) 1.57 (1.19–2.01) 0.001
High school 147 (48.8) 65 (21.6) 0.90 (0.66–1.23) 0.514 89 (29.6) 1.37 (1.02–1.84) 0.035
Economic status (2487)
Medium (R) 802 (50.9) 383 (24.3) 1 1 392 (24.9) 1 1
Low 28 (38.9) 29 (40.3) 2.17 (1.27–3.70) 0.004 15 (20.8) 1.10 (0.58–2.01) 0.78
Low/Medium 211 (44.4) 137 (28.8) 1.36 (1.06–1.74) 0.015 127 (26.7) 1.23 (0.96–1.58) 0.10
Medium/High 159 (44.9) 112 (31.6) 1.47 (1.12–1.93) 0.005 83 (23.4) 1.07 (0.80–1.43) 0.66
High 5 (55.6) 4 (44.4) 1.68 (0.45–6.27) 0.444 0 (0) -
Religion (2456)
Christian (R) 651 (46.8) 371 (26.7) 1 1 369 (26.5) 1 1
None 533 (51.0) 276 (26.4) 0.91 (0.75–1.10) 0.331 237 (22.7) 0.78 (0.64–0.96) 0.017
Others 6 (31.6) 6 (31.6) 1.76 (0.56–5.48) 0.333 7 (36.8) 2.058 (0.69–6.17) 0.198
Political inclination (2303)
Right (R) 232 (39.4) 202 (34.3) 1 1 155 (26.3) 1 1
Center 389 (47.3) 210 (25.5) 0.62 (0.48–0.80) <0.001 224 (27.2) 0.86 (0.66–1.12) 0.265
Left 534 (59.9) 171 (19.2) 0.37 (0.29–0.48) <0.001 186 (20.9) 0.52 (0.40–0.68) 0.001
OR = is calculated for each answer as compared to all the others; p-value = calculated for the Chi-square test group.
3.2. Variables with Influence on the Decision
As for the factors that had an influence on the decision to accept the vaccine, the
women had the most negative opinions (not being vaccinated/indecisive) as compared to
the men (p < 0.001). The participants with partners were more willing to be vaccinated
than those who were single, divorced, or widowed.
As for their age, it was observed that, as aged increased, so did the acceptance to
become vaccinated, so that the group with the greatest acceptance rate was those older
than 60 years old (59.2%, p = 0.001 vs. 18–29-years-old group). These data are in agreement
with the employment, with those who were retired being the ones who showed the great-
est acceptance of the vaccine (p = 0.013), while the students showed the greatest rejection
towards it (p = 0.039). Within the employed group, an influence was not observed of the
professional field when accepting the vaccine.
As for education, the university students had the greatest vaccine-acceptance rate,
while the other groups with less education showed the greatest hesitancy against accept-
ing the vaccine. Economic status was also an influencing factor when making the decision
to accept the vaccine, with the middle class showing the greatest acceptance, and the lower
class showing the greatest rejection (p = 0.004).
Religion was not a conditioning factor for the decision to accept or reject the vaccine;
however, the non-religious were less hesitant than those who were Christian (p = 0.017).
On the contrary, the political inclination was a determining factor, with the left-leaning
Int. J. Environ. Res. Public Health 2021, 18, 5272 5 of 12
participants being the ones who showed the greatest acceptance towards the vaccine, and
those who were right-leaning showing the greatest rejection and hesitancy (p < 0.001).
3.3. Acceptance, Rejection, or Hesitancy of the Vaccination through Time
Figure 1 shows the percentages of acceptance, rejection, or hesitancy of the vaccine
in the different periods prior to the start of the vaccination campaign. Aside from asking
the participants if they would be vaccinated in December, when the vaccination campaign
began in Spain, they were also asked if they would have been vaccinated if the vaccine
had been available in the months of August or October. A progressive increase was ob-
served in the percentage of individuals who would accept the COVID-19 vaccine as the
vaccination acquisition time neared, and the resulting decrease of rejection or hesitancy.
Figure 1. Evolution of vaccine acceptance through time.
3.4. Concerns and Sources of Information about the Vaccine
The “lack of information about secondary effects” and the “speed with which it was
created” were the most common reasons for hesitancy or rejection of the vaccine. The va-
riety of information related to the vaccine and the diversity of social agents responsible
for communicating the information were also some of the factors that were more associ-
ated with the high percentage of rejection or hesitancy among the population (Table 2).
The press, the communication media, and the social networks were the main sources
of information consulted by the population prior to the start of vaccination. To a lesser
degree, the population consulted other sources that were more specialized, such as the
webpages of organizations and associations related to health, or scientific bibliographic
databases. The social agents trusted by the population were the health workers (91.8%),
and it is through their recommendation that the percentage of vaccine acceptance (62.5%)
could be increased.
Table 2. Concerns associated with the Covid-19 vaccine and sources of information consulted by participants.
What Do You Think May be the Main Problem(s) that Leads to Doubts against Becoming Vaccinated with Covid-19 when the Vac-
cine Becomes Available?
Misinformation about the side effects that the vaccine may have 1757 (70.9)
How quickly its creation has taken place 1293 (52.2)
The variety of information from different media 693 (28.0)
That there are social agents of recognized prestige who doubt the vaccine 627 (25.3)
Int. J. Environ. Res. Public Health 2021, 18, 5272 6 of 12
Lack of consensus among political leaders in developing vaccination policies 377 (15.2)
There is no factor that raises doubts 35 (1.4)
From what sources do you collect information regarding the Covid-19 vaccine?
Written or digital press 1226 (49.5)
Television or radio 949 (38.3)
Social media 638 (25.8)
Official pages of health-related organizations and associations and medical bibliographic bases 499 (20.1)
Google-type search engines 458 (18.5)
No 9 (0.4)
Which of the following social agents do you trust the most?
Health 2295 (91.8)
Spiritual leaders 35 (1.4)
J
ournalists 11 (0.4)
Political 10 (0.4)
Other 15 (0.6)
None at all 99 (4.0)
Not clear 14 (0.6)
No answer provided 22 (0.9)
If the social agent you have selected recommends that you get the COVID-19 vaccine when it is ready, will you do it?
Yes 1555 (62.5)
No 329 (13.2)
Not clear 606 (24.3)
3.5. Multivariate Logistic Regression Analyses Showing Attitudes of the Participants as Factors
Associated with Acceptance of a COVID-19 Vaccine in Spain
The beliefs of the population associated to vaccines is a conditioning factor for the
acceptance or rejection of COVID-19. The individuals whose children have completed the
vaccination schedule, or those who habitually vaccinate against the flu every year, were
the ones who had the greatest willingness to accept the vaccine against COVID-19 (p <
0.001) (Table 3). Likewise, the participants who believed that the vaccines could cause the
disease it tries to prevent showed the greatest rejection and hesitation about the vaccine
(p < 0.001), while those with the opinion that without the vaccines there would be a greater
incidence of infectious diseases showed the greatest acceptance of the COVID-19 vaccine
(p < 0.001)
Table 3. Multivariate logistic regression analyses showing attitudes of the participants as factors associated with ac-
ceptance of a COVID-19 vaccine in Spain.
Variable (n) Accept Rejection Hesitation
n (%) n (%) OR (95% CI) p-Value n (%) OR (95% CI) p-Value
In the case that you have children, will you receive the COVID-19 vaccine when it becomes available? (2324)
No (R) 44 (6.1) 580 (79.8) 1 103 (14.2) 1
Yes 846 (96.1) 11 (1.2) 0.001 (0.001–0.02) <0.001 24 (2.7) 0.01 (0.01–0.02) <0.001
Not clear 220 (30.7) 49 (6.8) 0.02 (0.01–0.03) <0.001 447 (62.4) 0.87 (0.49–1.23) 0.475
Do you usually receive the vaccine against the flu? (2495)
No (R) 529 (38.1) 501 (36.1) 1 359 (25.8) 1
Yes 501 (63.2) 115 (14.5) 0.24 (0.19–0.31) <0.001 177 (22.3) 0.52 (0.42–0.65) <0.001
Occasionally 172 (55.0) 60 (19.2) 0.37 (0.27–0.51) <0.001 81 (25.9) 0.70 (0.52–0.93) 0.016
Do you believe that, without vaccines, the population would suffer more diseases, such as measles, chickenpox, etc.? (2499)
No (R) 26 (22.6) 77 (67.0) 1 12 (10.4) 1
Yes 1158 (51.5) 530 (23.6) 0.16 (0.10–0.24) <0.001 562 (25.0) 1.05 (0.53–2.10) 0.887
Not clear 19 (14.2) 70 (52.2) 1.24 (0.63–2.44) 0.526 45 (33.6) 5.13 (2.15–12.2) <0.001
Do you believe that vaccines can cause more diseases that they intend to prevent? (2500)
No (R) 906 (58.9) 307 (20.0) 1 325 (21.1) 1
Yes 113 (26.3) 202 (47.1) 5.28 (4.05–6.87) <0.001 114 (26.6) 2.81 (2.11–3.76) <0.001
Int. J. Environ. Res. Public Health 2021, 18, 5272 7 of 12
Not clear 186 (34.9) 168 (31.5) 2.67 (2.09–3.41) <0.001 179 (33.6) 2.68 (2.11–3.42) <0.001
In the case that you have children, do they have the vaccination calendar up to date? (2389)
No (R) 6 (20.0) 20 (66.7) 1 4 (13.3) 1
Yes 702 (49.9) 361 (25.5) 0.15 (0.06–0.39) <0.001 354 (25.0) 0.76 (0.21–2.70) 0.667
Not clear 2 (18.2) 3 (27.3) 0.45 (0.06–3.35) 0.436 6 (54.5) 4.5 (0.59–34.6) 0.148
Not children 442 (47.5) 264 (28.4) 0.18 (0.71–0.45) <0.001 225 (24.2) 0.76 (0.21–2.73) 0.678
OR = is calculated for each answer as compared to all the others; p-value = calculated for the Chi-square test group.
Table 4 shows the results from the question of if the state of health had an influence
on the decision of accepting the COVID-19 vaccine. The results showed a higher ac-
ceptance from the participants who suffered from immunodepression (p = 0.014), over-
weightness (p = 0.002), hypertension (p = 0.006), respiratory disease (p = 0.001), or hyper-
cholesterolemia (p = 0.032). However, cancer patients showed a significant hesitancy (p =
0.003).
Table 4. Multivariate logistic regression analyses showing health status as factor associated with acceptance of a COVID-
19 vaccine in Spain (n = 2457).
Variable Accept Rejection Hesitation
n (%) n (%) OR (95% CI) p-Value n (%) OR (95% CI) p-Value
Cancer
No 1189 (48.8) 651 (26.7) 0.46 (0.14–1.50) 0.196 594 (24.4) 0.21 (0.07–0.59) 0.003
Yes (R) 5 (21.7) 6 (26.1) 1 12 (52.2) 1
Respiratory disease
No 1121 (47.8) 627 (26.7) 0.46 (0.14–1.5) 0.456 597 (25.5) 4.35 (2.15–8.80) 0.001
Yes (R) 73 (65.2) 30 (26.8) 1 9 (8.0) 1
Diabetes
No 1156 (48.3) 643 (26.9) 1.51 (0.81–2.80) 0.193 591 (24.8) 1.62 (0.84–3.14) 0.146
Yes (R) 38 (59.4) 14 (21.9) 1 12 (18.8) 1
Cardiac disease
No 1170 (48.5) 647 (26.8) 1.33 (0.63–2.79) 0.456 593 (24.6) 0.94 (0.47–1.85) 0.936
Yes (R) 24 (51.1) 10 (21.3) 1 13 (27.7) 1
Liver disease
No 1187 (48.5) 655 (26.8) 1.93 (0.40–9.32) 0.413 606 (24.8) - -
Yes (R) 7 (77.8) 2 (22.2) 1 0 (0.0) 1
Renal disease
No 1190 (48.7) 654 26.8) 0.73 (0.16–3.28) 0.685 600 (24.5) 0.34 (0.09–1.20) 0.092
Yes (R) 4 (30.8) 3 (23.1) 1 6 (46.2) 1
Hypercholesterolemia
No 1122 (48.1) 629 (26.9) 1.44 (0.92–2.26) 0.109 584 (25.0) 1.70 (1.05–2.78) 0.032
Yes (R) 72 (59.0) 28 (23.0) 1 22 (18.0) 1
Immunodepression
No 1162 (48.3) 651 (27.0) 2.99 (1.24–7.18) 0.014 595 (24.7) 1.49 (0.75–2.98) 0.259
Yes (R) 32 (65.3) 6 (12.2) 1 11 (22.4) 1
Overweightness
No 995 (47.3) 583 (27.7) 1.58 (1.18–2.10) 0.002 524 (24.9) 1.28 (0.97–1.69) 0.084
Yes (R) 199 (56.1) 74 (20.8) 1 82 (23.1) 1
Hypertension
No 1081 (48.0) 619 (27.5) 1.70 (1.16–2.49) 0.006 553 (24.5) 1.09 (0.78–1.54) 0.619
Yes (R) 113 (55.4) 38 (18.6) 1 53 (26.0) 1
OR = is calculated for each answer as compared to all the others; p-value = calculated for the Chi-square test group.
Int. J. Environ. Res. Public Health 2021, 18, 5272 8 of 12
4. Discussion
4.1. Population: Vaccine Acceptance
At the end of 2020, the massive vaccination campaigns begun in Spain, prioritizing
the most vulnerable individuals after the approval of two vaccines (Comirnaty by Pfizer-
BionTech, and COVID-19 Vaccine by Moderna) by the European Medicines Agency [26].
The common objective of every vaccination campaign is to create a high degree of confi-
dence among the population, which will be key for achieving the high rates of vaccination
coverage needed for reaching herd immunity [21,27,28].
The present study demonstrated the low acceptance of the vaccine against COVID-
19 among the Spanish population (48.3%) at the end of 2020, just before the start of the
vaccination campaign. There are only two previous studies that had analyzed the percent
of acceptance of the new COVID-19 vaccine in the Spanish population in the period prior
to the start of the vaccination campaign [16,20].
In the study by Lazarus et al., the population was asked about acceptance in June
2020, with 74.33% stating that they would accept it when it became available [16], while
the study by Eguia et al. asked individuals the same question between September and
November 2020, with a 77.5% rate of acceptance observed [20]. These data are higher than
the results from our study, where the acceptance in August was only 33.7%, but then pro-
gressively increased to 48.3% in December. The study by Lazarus et al. did not show the
sociodemographic characteristics of the population, while the study by Eguia et al. only
showed data referring to age, sex, or profession, which did not allow us to determine if
the differences found were due to possible population biases.
In any case, in both studies, the participation was lower than 800 individuals, which
is inferior to the sample utilized in our study (n = 2501).
Our results showed a higher rejection than other studies conducted in March in
France, and in May in the USA, where only 26% and 20%, respectively, would reject the
vaccine [29,30], which makes us think about an increase in acceptance at the start of the
vaccination campaign. However, the hesitancy could even increase after the introduction
of the vaccine, as observed in France with the H1N1 pandemic, when only 10% received
the vaccine as compared to the 27% who had the intention of being vaccinated [6–8]. To
avoid this situation, the suggestion was made to periodically analyze, during the vaccina-
tion campaign, the profile of individuals who have doubts about the effectiveness of vac-
cines in Spain, where vaccination coverage is the highest in Europe in the children popu-
lation but decreases in the adult stages, to implement measures that guarantee a high per-
centage of acceptance of the vaccine [3].
4.2. Acceptance, Rejection or Vaccine Hesitancy through Time
The main statistically significant independent variables associated with vaccine ac-
ceptance were being male, older, living with a partner, and being retired. These data were
in agreement with those from a European poll, where the men older than 55 years old
were more willing to vaccinate [31]. However, not all the studies coincided with the age
of greatest acceptance; thus, as opposed to our study, the groups which showed the great-
est rejection were those older than 75 years old, despite being a very vulnerable age group
[30]. The type of employment did not have an influence on vaccine rejection; however, a
lower level of education was associated with the rejection of vaccines, as previously de-
scribed in other studies conducted in Syria and Australia [32–34]. There was evidence that
political leanings played an important role on the attitude associated to vaccines. Thus, in
France, those who had voted for an extreme left or extreme right candidate had a higher
probability of rejecting the COVID-19 vaccine [19]. Our study confirmed the influence of
the political leaning when accepting the vaccine; however, in Spain, the left-leaning voters
were the ones who showed the greatest acceptance, and the right-leaning ones who
showed the greatest rejection.
Int. J. Environ. Res. Public Health 2021, 18, 5272 9 of 12
The growing anti-vaccine sentiment in the last few years is known [5]. The conse-
quences of vaccine hesitancy are also reflected in that some parents ask for the delay of
the vaccine dose, so that they shift away from the recommended vaccination calendar [35].
In this work, 24.9% hesitated being vaccinated, waiting for more data on the safety of the
vaccine [17]. In this sense, our study showed that those who had children and complied
with the vaccination calendar were more willing to be vaccinated. At present, vaccines for
those younger than 16 are not available, so that the feeling of protection after immuniza-
tion could be the reason behind the acceptance in this population group [36]. Being vac-
cinated against the flu in other seasons [37,38] and a completed children’s vaccination cal-
endar of individuals with children were also variables that exerted a very favorable trend
in vaccine acceptance.
4.3. Concerns and Sources of Vaccine-Related Information
The manifestation of “fear of the secondary effects” was repeated in this and other
studies as the main cause for vaccine hesitation [4,20,39]. The high percentage of hesitation
in the Spanish population could be partly explained by the rejection of the government’s
management in 2020, as indicated by the low confidence in the politicians, the concern
when facing a lack of political consensus, and the influence of the political inclination
when accepting the vaccine, as shown in our study [30,40]. It is known that mistrust in
political populism can promote the feeling against vaccination, creating confusion and
provoking mistrust [10,33]. Thus, familiarity and trust on the messenger, the coherence of
the messages, and the political management, are fundamental for succeeding against vac-
cine hesitancy [12,41]. In crisis situations, the interpersonal trust tends to increase, while
the institutional trust tends to decrease, mainly because of the mistrust of the govern-
ment’s recommendations [3,42]. Politicians, more than health professionals, are the public
face of crisis management, a mistake that was demonstrated in France with the manage-
ment of the H1N1 flu in 2009 [6–8]. The rupture of political unity and the doubts associ-
ated with the speed with which the vaccine was developed resulted in a low acceptance
of the vaccine (only 10% of the population was vaccinated) [7,43].
4.4. A multivariate Logistic Regression Analysis Shows the Attitudes of the Participants as Fac-
tors Associated to COVID Vaccine Acceptance in Spain
Our results show that vaccine acceptance increases over time, as the period of vac-
cination nears in Spain, surely influenced by the increased information related to it, but
the lack of political unity and consensus, together with the doubts of social agents with
recognized prestige, could increase the doubts of the population. The recommendation
and advice from a health professional are therefore key for achieving a high vaccination
coverage in the vaccination calendar [13,17,34] and a high herd immunity [44]. In this
work, the health experts were pointed out as the main agents in which the population
would place its trust. As for the sources of information, the press and the radio were cited
as the most utilized, along with the social networks, which represented a high percentage
(25%). These last, more social sources of information could be linked to false news or non-
contrasted statements that could derive into an increased hesitancy [39]. Due to this, sci-
entists from the area of health could be ones who must play the information dissemination
role for the population, to transmit the latest findings [45].
Another of the main concerns of the Spanish population was the speed with which
the COVID-19 vaccine was created. Although the unprecedented situation we are cur-
rently living in demanded the acceleration in the development of the vaccine, conflicts of
interests were put forward [46]. The lack of knowledge about the secondary effects of a
new vaccine increases the level of mistrust, also thanks to contradictory information and
“fake news” that reach the population through different means. In this sense, the commu-
nication media, the traditional ones, and the social networks, must significantly contribute
to address these fears [9,43,47]. The WHO points out that transparency and personalized
Int. J. Environ. Res. Public Health 2021, 18, 5272 10 of 12
information on the evolution of the epidemiological risk in the community are key aspects
for obtaining the trust of the population [27,28].
4.5. Study Limitations
The limitations of the study were that the results are strongly marked by a social
context of constant changes in confinement policies in Spain and a great variability in the
information offered to the population about the vaccines that were not yet available. Re-
garding the questionnaire, a non-validated new survey was applied, and the methodology
used for its dissemination meant that all the data were self-reported by the participants,
with a high level of education and a high participation of health professionals, which
could result in response bias. However, the large sample obtained and its anonymity were
some of its strengths.
4.6. Practical Implications
In the present work, as practical implications and future research, we evaluated the
intention to become vaccinated. We obtained a gradual increase in the acceptability of the
vaccines as their availability came closer, but this percentage could decrease with the final
administration if adequate communication strategies with the population are not imple-
mented, during a world distribution scenario in 2021 [48,49].
The vaccination strategies for 2021 should be adapted to a reality in which a society
is concerned about the pandemic, where the determinants of vaccine hesitancy are com-
plex and varying across time, place, and type of vaccine, by identifying the barriers in the
current context [24,50].
5. Conclusions
In the Spanish population analyzed prior to the start of the vaccination campaign at
the end of 2020, the percentage of acceptance of the new vaccines aimed at preventing the
COVID-19 disease was low. Disinformation and the lack of political consensus are the
main doubts of the Spanish population associated to the new vaccines against SARS-CoV-
2 in an extraordinary scientific-health context.
In this study, the participating population had a low rate of acceptance of the vaccines
destined to fight against COVID-19, caused by concerns about side effects, the speed with
which it was created, and the thought that it may not be reliable. Communication with the
population must be as personalized as possible, as we found the existence of age groups,
levels of education, political ideology, beliefs about vaccines in general, and the state of
health itself, which have an influence on vaccine acceptance or rejection.
There is, thus, a need for monitoring and planning of the vaccination campaign,
which, in many countries, will be accelerated [47,51]. Trust in the institutions is funda-
mental to guarantee the levels of vaccination that lead to herd immunity.
Author Contributions: Conceptualization, N.R.-B. and J.T.; investigation and data curation, N.R.-
B., S.M.-N., J.M.B.-R., and A.J.F.-G.; statistical analysis, J.S.-M.; writing–original draft, N.R.-B., S.M.-
N., J.M.B.-R., and J.S.-M.; writing—review and editing, N.R.-B., J.S.-M., and J.T. All the authors con-
tributed substantially to the study design data analysis and interpretation of the findings. All au-
thors have read and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: The study was conducted according to the guidelines of the
Declaration of Helsinki and followed the Ethics Committee of CEU University standards.
Informed Consent Statement: Informed consent was obtained from all subjects involved in the
study.
Data Availability Statement: The data presented in this study are available on reasonable request
from the corresponding author. The data are not publicly available, due to ethical requirements.
Int. J. Environ. Res. Public Health 2021, 18, 5272 11 of 12
Acknowledgments: We would like to thank all the students who kindly agreed to participate in this
study. The researchers also want to thank university (CEU) for their willingness to participate.
Thanks to Mario Fon for his help with the translation of this article.
Conflicts of Interest: The authors declare no conflict of interest.
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