Vaccination and immunization are often used interchangeably; however, vaccination involves introducing a vaccine to protect against a specific disease, while immunization is the process of becoming protected against a specific disease through vaccination1.

Vaccination is a major achievement in global health and is considered one of the greatest public health accomplishments of the 20th century2. It is highly cost-effective for preventing infectious diseases3,4. Over 20 life-threatening diseases have become preventable through vaccination, significantly improving quality of life5-7. Scientists worldwide tacitly agree with the consensus that vaccines are generally safe and effective2. However, vaccine hesitancy, defined as reluctance or refusal to receive vaccinations, remains a concern8-10.

Available COVID-19 vaccines are effective against variants of the virus3,4; however, vaccine hesitancy towards COVID-19 vaccination persists9,10. In Croatia (RH), vaccination against COVID-19 is carried out with vaccines that are approved by the European Medicines Agency (EMA) (Pfizer, Moderna, AstraZeneca—all manufacturers, and Johnson & Johnson), while in Bosnia and Herzegovina (BH), it is possible to be vaccinated with the previously named vaccines and some WHO-approved vaccines that are not approved by the EMA, such as Sinopharm and Sinovac.

According to the Croatian Institute of Public Health and the Central Bureau of Statistics, over 95% of the total number of infected people were successfully cured in the RH. The total number of vaccination doses administered per 100 people is 104.53 in RH and 62.15 in BH11. In Croatia (RH), approved vaccines by the European Medicines Agency (EMA) are used, while in Bosnia and Herzegovina (BH), WHO-approved vaccines not approved by the EMA are also administered. Specific entry requirements apply in each country11.

Our study examines the impact of educational interventions on COVID-19 vaccination and vaccine hesitancy. Despite mandatory childhood vaccination policies against tuberculosis, diphtheria, tetanus, pertussis, poliomyelitis, Haemophilus influenzae type B, hepatitis B, measles, rubella, and parotitis in both countries (BH and RH) and a vaccine against pneumococci only in Croatia, there is limited systematic education on vaccine-preventable diseases12,13. We aim to assess knowledge, attitudes, and behaviors related to vaccine immunization among students14-17. The study focuses on COVID-19 vaccination awareness and explores correlations between knowledge, attitudes, and practices among medical and non-medical students at the University of Sarajevo (UNSA) in BH and the University of Rijeka (UNIRI) in RH. We compare medical and non-medical students, drawing comparisons with relevant studies18.


Study population and design

A cross-sectional, descriptive study was conducted in Sarajevo Canton and in Rijeka, from 18 February to 1 May 2021, among students of different affiliations from the UNSA and the UNIRI and through a created web-based survey – Google Forms. Among the latter, there were also students, mostly (85.3%) from Germany, who studied medicine in English (UNIRI-E). Eligibility criteria to participate in the survey were that they should be students of the two mentioned universities, social media users, understand the study purpose, and be willing to participate voluntarily.

The questionnaire

Data collection involved a structured self-administered questionnaire based on existing foreign instruments, designed using Google Forms after conducting a literature review12-16. The questionnaire, consisting of 31 questions, assessed students’ knowledge, attitudes, and practices regarding vaccine immunization and the COVID-19 pandemic. The first part collected sociodemographic information such as age, sex, academic year, university attended, municipality of residence, vaccine immunization profile, and source of education. The second part assessed knowledge, attitudes, and practices related to vaccine immunization, including COVID-19.

Further, the questionnaire included 10 items on a five-point agreement scale (from 1=‘strongly disagree’ to 5=‘strongly agree’) designed as a Likert scale assessing misconceptions about potential vaccination risk. The questionnaire, previously validated and assessed for reliability by using Cronbach’s alpha test, was shared by link through student affairs offices and social media groups (Facebook, WhatsApp). It included an introduction to the study, eligibility criteria, a confidentiality declaration, and anonymity. It took approximately 5–7 minutes to complete. A reminder was given to complete the questionnaire within four weeks. The responding student population was 377 from UNSA and 789 from UNIRI, which is approximately 1.4% and 4.64% of the total estimated student population of this university, respectively. Student knowledge was quantified by questions that had one correct response and were scored with one point. The mean of students’ total scores was calculated along with the standard deviation, which was compared between medical and non-medical students using the Student’s t-test. The distribution of the scores was tested by the Kolmogorov-Smirnov test, with p=0.05.

Statistical analysis

Completed questionnaires were extracted from Google Forms and exported to Microsoft Excel 2010 for cleaning and coding. The cleaned data were exported to Statistical Package for Social Science (SPSS) version 25 software (IBM Corporation, Armonk, New York). Basic standard methods of descriptive statistics, or summarizing features of data collection, were applied. A chi-squared test was performed to assess differences in proportions of qualitative variables between groups, and a t-test was used to detect differences between quantitative variables. The level of significance was set to p<0.05.


A total of 1166 students from the UNSA in BH, and UNIRI in RH responded to the survey. The majority of the responders were female (n=774), with a mean age of 22.58 ± 2.62 years (UNSA) and 23.33 ± 1.71 years (UNIRI). In the study were 392 male participants, with a mean age of 23.08 ± 3.34 years (UNSA) and 24.27 ± 2.98 years (UNIRI). There was a significant difference in sex distribution (χ2=25.01, p<0.001). Regarding the distribution of participants according to the academic year of study, the most prevalent group of students belonged to the second academic year (34.7%) (UNSA) and the first academic year (27.1%) (UNIRI), respectively. The demographic characteristics of the participants were analyzed depending on the place of residency, with the largest number of participants coming from the urban area (70% UNSA vs 54.9% UNIRI), and significant demographic differences were found (χ2=40.26, p<0.001).

More than two-thirds of students have shown a positive attitude about mandatory vaccination (χ2=105.76, p<0.001). A total of 89.3% of medical students from the UNSA were fully vaccinated, and 91.3% of medical students from the UNRI. When students were asked whether they were considered sufficiently informed regarding vaccination, a significant difference was observed (χ2=106.06, p<0.0001). Additionally, there was a significant difference in the participant attitude towards vaccination (χ2=125.84, p<0.0001), which was predominantly positive in the UNIRI group of students (n=450; 61.3%). The most powerful information source for UNSA and UNIRI students was healthcare professionals, followed by the Internet and social networks, professional literature, TV and media, friends and families, and magazines (Table 1).

Table 1

Attitudes, vaccination status and sources of information among medical and non-medical students about immunization during the COVID-19 pandemic, February–May 2021 (N=1166)

QuestionResponseUNSA studentsUNIRI studentsUNIRI-E studentsχ2 p
What is your attitude about vaccination?Negative169.53315.9206.010526.247.3125.84
What is your vaccination status?Partially vaccinated169.52210.6267.87619.02952.7108.63
I don’t know21.231.430.9205.000.0
Fully vaccinated15189.318287.930491.330576.12647.3
Do you think that you are sufficiently informed about vaccination?Yes7745.67536.217352.014937.23360.0106.06
What are your experiences with vaccination until now?Negative84.794.351.5215.223.625.797
No defined attitude63.6136.330.9266.511.8
Do media have a great influence on the formation of attitudes about vaccination?Yes14485.217886.027682.928370.64072.734.05
I don’t know63.673.4175.1348.523.6
Do you think that vaccination should be mandatory?Yes11668.613163.325275.717944.63054.5105.76
I’m not sure3118.33918.85015.08320.759.1
What source of vaccination data do you use?Magazines4828.46631.9247.25814.547.3-
Internet/social networks9153.811957.59929.719849.41629.1
Family and friends4124.39646.4185.45313.247.3
Scientific literature and faculty6739.68239.69428.26015.059.1
Healthcare professionals11568.012761.412537.514636.42443.6
I am not informed00.031.430.9194.735.5
Which of the mandatory vaccines do you consider dangerous and/or unnecessary?BCG74.1199.282.492.223.6-
COVID vaccines (not required)
Hepatitis B63.62110.120.6112.700.0

[i] UNSA: University of Sarajevo. UNIRI-E: University of Rijeka (studies in English).

More than a third of students believed that after vaccination, they will be immune to the disease. Between 35% and 40% of students believed vaccines will have long-term negative consequences. Furthermore, roughly 40% believed that administering more vaccines at once will increase the risk of side effects. Approximately one-quarter of students believed that vaccines cause autism.

In terms of pharmaceutical companies creating infections to increase profits, 46.4% of UNIRI students studying medicine in English agreed with the statement, compared to 16.0% of medical students at the University of Sarajevo (p<0.001) (Table 2).

Table 2

Attitudes and knowledge regarding vaccination among medical and non-medical students about immunization during the COVID-19 pandemic, February–May 2021 (N=1166)

ItemResponseUNSA studentsUNIRI studentsUNIRI-E studentsχ2 p
I think that I cannot get the disease if I have been vaccinatedDisagree13076.915273.424774.230475.84379.61.453
Some of the vaccines can cause long-term adverse effectsDisagree10964.515172.926880.528771.64580.417.58
Giving more vaccines at the same time increases the risk of side effectsDisagree11065.113565.226780.228571.14173.219.93
The number of scientific data about usefulness of vaccination is insufficientDisagree13680.517484.123771.232881.83562.525.32
Vaccines cause more harm than goodDisagree10360.913565.210631.825162.61017.9118.33 <0.001
Mandatory vaccination is an encroachment on domain of human rightsDisagree13076.915876.323370.032079.83969.610.806
The pharmaceutical industries are creating infections with the goal of increasing earningsDisagree14284.016680.219057.132180.03053.679.268
Vaccines are a trigger for autism and autoimmune diseasesDisagree12574.015675.424673.931077.34071.41.837

[i] UNSA: University of Sarajevo. UNIRI-E: University of Rijeka (studies in English).

Table 3 summarizes the assessment of all self-reported COVID-19 preventive behaviors and risk perceptions. Prior to this study, every fifth UNIRI student and nearly every fourth UNSA student tested positive for COVID-19. We discovered that approximately 20–30% of them were concerned about COVID vaccines and their potential negative impact on their health.

Table 3

Attitudes and practices regarding COVID-19 among medical and non-medical students about immunization during the COVID-19 pandemic, February–May 2021 (N=1166)

QuestionResponseUNSA studentsUNIRI studentsUNIRI-E studentsχ2 p
Have you been COVID-19 positive?Yes3218.95627.17522.57719.21527.380.984
I don’t know2615.42813.55315.96516.200.0
I am not sure21.221.00030.7712.7
Do you fear for your own health if you do not receive the COVID-19 vaccine?Yes4224.857234.789628.834410.972240.081.841
I don’t know2213.023617.395015.024410.9723.6
I have been informed enough about the COVID-19 vaccine by the media and health professionalsStrongly disagree4426.08440.640128220.4712.7105.17
Neither agree nor disagree4627,24119.810330,911929.72138.2
Strongly agree21.294.3257.5174.2610.9
What do you consider current COVID-19 vaccines safe?Yes4426.046631.818154.3511127.683665.5103.54
I don’t know7242.607134.309829.4313834.411629.1

[i] UNSA: University of Sarajevo. UNIRI-E: University of Rijeka (studies in English).

Only 29.7% of 377 UNSA students believed that vaccines against COVID-19 are safe, while 41% of UNIRI students believe the same. UNIRI students studying medicine in English have the most informed views on vaccines.

There was a significant difference in students’ attitudes toward the utility of vaccination (χ2=14.5, p<0.001) and the pharmaceutical industry’s desire to make a profit (χ2=34.9, p<0.001).

One of the study’s goals was to see if there were any differences in student attitudes, knowledge, and perceptions about vaccination between medical and non-medical students. Both groups demonstrated a lack of knowledge. Even so, there were statistically significant differences between medical (mean=2.51, SD=1.23) and non-medical students (mean=2.03, SD=1.30), t-test=6.35, p<0.001 (Table 4).

Table 4

Differences in attitudes and knowledge of medical and non-medical students regarding immunization during the COVID-19 pandemic, February–May 2021 (N=1166)

ItemResponseMedical studentsNon-medical studentsχ2p
I think that I cannot get the disease if I have been vaccinatedDisagree42075.545674.80.0960.757
Some of the vaccines can cause long-term adverse effectsDisagree42175.743972.02.1160.146
Giving more vaccines at the same time increases the risk of side effectsDisagree41875.242068.95.760.016
The number of scientific data about usefulness of vaccination is insufficientDisagree40773.250382.514.548<0.001
Vaccines cause more harm than goodDisagree21839.238763.468.428<0.001
Mandatory vaccination is an encroachment on domain of human rightsDisagree40172.147978.56.4410.011
The pharmaceutical industries are creating infections to increase their profitDisagree36064.748980.234.919<0.001
Vaccines are a trigger for autism and autoimmune diseasesDisagree41073.746776.61.2380.266
Correct responsesMean (SD)2.51 (1.23)2.03 (1.30)t-test
p <0.001


This study aimed to evaluate students’ knowledge, attitudes, and practices regarding the COVID-19 pandemic and immunization programs18. Vaccine hesitancy, caused by a loss of confidence in vaccines and public institutions, poses challenges for public health authorities2. The objective of this study was to emphasize the importance of targeted interventions to modify the knowledge, practices, and attitudes of medical students in relation to their future roles in immunization programs15-18. The survey included 1166 students from two universities in Bosnia and Herzegovina and the Republic of Croatia, representing different study years and affiliations. The research aimed to evaluate the knowledge, attitudes, and preventive behaviors of medical students compared to non-medical students in relation to immunization and the COVID-19 pandemic18. Assessing medical students’ knowledge and preventive behaviors is crucial, as they are at the frontline in the fight against the pandemic15-17.

The initial results showed a predominantly positive attitude toward vaccination programs among all participants (56.5% in BH and 61.3% in RH). The questionnaire also assessed the coverage of mandatory vaccines, considering the influence of anti-vaccination propaganda, particularly prevalent on the internet14. Literature search results highlighted the significant presence of anti-vaccination websites in online search results and Facebook pages dedicated to opposing vaccination19-21. Nonetheless, the majority of students in the study were fully vaccinated (p<0.0001), indicating a positive trend despite anti-vaccination propaganda21. These findings align with the positive attitudes of Serbian medical students toward immunization22,23. Healthcare professionals were identified as the most influential source of vaccination information, followed by the internet and social networks, professional literature, TV and media, and friends and family24. Similar studies have confirmed the strong influence of social media and the news media in shaping vaccination attitudes25,26.

Limited data are available on the vaccination-related knowledge, practices, and attitudes of students in Southeast Europe13. Medical students demonstrated more knowledge about vaccination, as expected. There were significant differences in vaccine knowledge between medical and non-medical students (p<0.001)27. However, a substantial number of students from both medical faculties expressed the belief that vaccines cause more harm than good, highlighting the need for interventions to improve vaccination education in both clinical and preclinical courses.

Strengths and limitations

The strengths of this study are the comprehensive questionnaire, the multicentric international study, and the comparison of two populations with different educational backgrounds. The limitations of the study are that the majority of students were female and that the results are cross-sectional and hence cannot attribute causality. Furthermore, the results may be subject to reporting bias.


The results of this study indicate that there is an evident need to further educate young people about vaccination. Bosnia and Herzegovina, and Croatia, are faced with a problem of high-risk populations regarding vaccination hesitance28, thus, vaccination knowledge and attitudes of medical students are of particular interest. The outcomes of this research could be useful for medical educators to ensure that medical students have better knowledge compared to students of other faculties.