Evaluation of knowledge and barriers of influenza vaccine uptake among university students in Saudi Arabia; a cross-sectional analysis

Ethical statement

Ethical approval was obtained from the Institutional Committee of Bioethics (Reference no.: 06-05-43). The participation in this study was on a volunteer basis and written informed consent was obtained from each participant. A brief description of the study and its purpose was also provided at the beginning of the study. The anonymity of the respondents was ensured before analysis.

Study site and design

This web-based cross-sectional study was conducted among students from Jouf University, Saudi Arabia. Inclusion criteria for recruitment into the present study were: (1) All the students enrolled in the university, regardless of their discipline and year of study, (2) willing to participate, (3) age 18 years and above, (4) either male or female, and (5) were able to write and read Arabic or English. All the respondents not fulfilling the inclusion criteria were excluded from the study. The methodological flow chart of the current study is described in Fig. 1.

Study duration

Data was collected over five months period, starting from February to June 2021.

Sample size and sampling technique

The minimum sample size was estimated using the Cochran formula for sub-groups in a population: ${\displaystyle n=\frac{2Z^{2}pq}{d^2}.}$

Where, n = desired sample size, Z = level of confidence according to standard normal deviation (1.96 corresponding to 95% confidence interval), p = proportion in the target population having a particular characteristic, q = proportion in the target population not having particular characteristics, i.e., 1-p, and d = degree of accuracy required (0.05). The minimum population size was adjusted for non-response and drop-out of 25% with the power of 0.80, resulting in a required sample size of 424.

Study instrument

A 31-items questionnaire was developed after reviewing previous literature (Rogers, Bahr & Benjamin, 2018; Benjamin & Bahr, 2016). The panel of experts reviewed the study instrument for the content and face validity, and their recommendations were considered in the finalized questionnaire. The validity of the questionnaire was determined by piloting a sample of 30 students to ascertain if the questions were valid and understandable. This data from the pilot study was not included in the final results. The reliability of the questionnaire was assessed by a Cronbach alpha value (0.77), which indicated the adequacy of the survey tool. The study instrument comprised of four sections:

1. Section I had questions related to demographics, including age, gender, marital status, the field of education, and questions related to flu vaccination status.

2. Section II consisted of thirteen true and false statements related to the knowledge of students about the flu vaccine. These items were 1 for “correct” answers and 0 for “wrong” and “don’t know” responses. The maximum cumulative knowledge score was 13. The knowledge score was further categorised into three levels, i.e., poor knowledge (score ≤ 5), moderate knowledge (score 6 to 9), and good knowledge (score ≥ 10) (Salman et al., 2020; Srichan et al., 2020). Section III consisted of questions identifying the barriers influencing the receipt of the flu vaccine. Eleven barriers in this study were broadly classified under five categories. These five categories of barriers included affordability (1 item), accessibility (2 items), negative perception (5), lack of recommendation (1 item), and religious and cultural restrictions (2 items). All the responses were collected on a 5-point Likert scale (“Agree”, “Strongly agree”, “Neutral”, “Disagree”, to “Strongly disagree”). Responses were collapsed for further analysis by re-coding the values for strongly agree and agree as ’1”; the values for disagree, strongly disagree, and neutral as ’0”. The maximum barrier score was 11. Percentage agreement was calculated for the participants who agreed to the statements. Statements portraying the perceptions and barriers were ranked to determine the significant barriers associated with vaccine uptake (Bali et al., 2013; Eppes et al., 2013). Moreover, negative perceptions were specifically assessed in relation to vaccine uptake.

3. Section IV consisted of statements regarding the willingness of the students to take the flu shots. Willingness was determined using a set of seven questions with a response of “Yes”, “No” and “Don’t know”. These responses were re-coded and dichotomized, i.e., 1 for agreeing to the statement and 0 for “disagree” and “don’t know” responses. The maximum willingness score was 7. The level of willingness was stratified into three levels: poor level (≤ 2 score), moderate level (3–5 score), and good level (≥ 6 score) of willingness to receive flu vaccine (Srichan et al., 2020; Eppes et al., 2013).

Data collection

Convenient sampling was used and all the students were invited via electronic mail. Students’ e-mail addresses were obtained from the university database. Researchers approached the students via e-mails, with a link to the questionnaire enclosed with it. They explained the purpose of the survey, keeping the anonymity and confidentiality of the respondents. Incomplete responses were excluded from further analysis. The data collected online was scrutinised and converted to an excel sheet. Only completed responses were considered and subjected to further analysis. Survey responses were kept anonymous and were only accessible to the researchers.

Operational definitions

Vaccinated participants were referred to those “who took the flu shot before the arrival of the winter season” and non-vaccinated were “those who did not receive it before winter”. Participants’ knowledge was stratified into three levels: Good, moderate, and low knowledge referred to knowledge score ≥10, 6-9, and ≤ 5, respectively. Barriers mean factors hindering vaccine uptake. Perception refers to participants’ beliefs regarding the vaccine uptake, whereas negative perception refers to the negative thinking of participants about the vaccine. The perception score is referred to as “the mean cumulative perception score”. Percentage agreement is “the % of participants who agreed to the statement or item of the study toll”. The participant was considered concerned if he/she agrees with the negative perception: extremely concerned, quite concerned, and little concerned. Vaccine acceptors referred to the “participants who agreed to take the vaccine every year”. Vaccine hesitant referred to the “participants who disagreed to take the flu vaccine every year”. Vaccine ambivalent referred to the “participants who were not sure to receive the flu vaccine every year”.

Data analysis

Data analysis was done using SPSS version 21. Shapiro–Wilk and Kolmogorov–Smirnoff tests were used to evaluate the distribution of the data obtained from the survey. Continuous data were expressed as mean (±SD), while categorical data were summarised as frequency (%). Categorical data were compared using the Chi-square test or the Fisher exact test, where appropriate. The relative importance index (RII) was used to determine the pertinence of the statements, identifying and ranking the barriers to vaccine uptake. The value of RII ranges from 0 to 1; the value closest to 1 corresponds to the highest rank and main barrier. RII equation: ${\displaystyle RII=\frac{\sum W}{\left(A\ast N\right)}.}$

Where, N is the total number of participants, A is the highest weight, and W is the weight given to each statement by the participant (1: strongly disagreed to 5: strongly agreed). Furthermore, percentage agreement was calculated to evaluate the % of people who agree with the statement. To evaluate the % agreement to the negative perception statements, the 5-point Likert scale was collapsed to two points i.e., “agree” and “disagree”. Mean knowledge and perception score were compared between the two groups using an independent t-test. Association between demographic variables, knowledge, perception, and willingness with vaccine uptake were evaluated using Pearson correlation, simple linear regression, or chi-square, where appropriate. Multivariate analysis using a logistic regression model was run to determine the association between the independent demographic variables with the flu vaccine uptake. The variables having a statistically significant value of 0.05 were included in the bivariate analysis. These predictive variables that showed significant association (p-value <0.05) on bivariate analysis were further included in a multivariable logistic regression model. Variables included in the model were age, gender, marital status, the field of education, knowledge, perception, and willingness. A 95% confidence interval (CI) was calculated to reveal the odds ratio (OR). P-value of <0.005 was considered statistically significant.

Characteristics of study participants

Of the total 790 participants, 246 (31.1%) belonged to health sciences, and 544 (68.9%) were from non-health science disciplines. The mean age of participants was 21.40 ± 1.94 years, and most (83.9%) were single. There was an almost equal distribution of males (401, 50.8%) and females (389, 49.2%) gender. Table 1 summarises the demographic characteristics of the study participants.

Vaccination rate among study participants

The majority of the participants (n = 549, 69.5%) did not receive a flu shot before the winter season. There was a significant difference among the health sciences (HS) and non-health sciences (NHS) group w.r.t receipt of flu jab (flu shot before joining university: (HS:58.9% vs. NHS:35.5%; p < 0.001); and before arrival of the winter: (HS:38.6% vs. NHS:26.8%; p = 0.001)).

Knowledge regarding influenza vaccination

One-third (67.6%) of study participants had moderate knowledge about the influenza vaccination with a mean knowledge score of 7.81 ± 1.96, differing significantly among the HS and NHS group (p < 0.001). Surprisingly, only 20.4% of students indicated good knowledge, with a majority being from the HS group (n = 88, 54.7%) (Table 2). Furthermore, high knowledge score was associated with gender (p-value < 0.001), field of education (p-value < 0.001), and year of education (p-value < 0.001). The knowledge score significantly differed across vaccinated and non-vaccinated participants (p-value 0.015; F = 3.152). Interestingly, females scored higher than males (8.48 ± 1.81 vs. 7.17 ± 1.88; p < 0.001). Item-wise analysis showed that most of the participants correctlyresponded that vaccines should be given to all persons aged six months and greater (n = 605, 76.6%), the vaccine reduces the severity and duration of flu (n = 576, 72.9%), and improves the immunity (n = 575, 72.8%).

Barriers to receiving flu vaccine

Our analysis compared 11 potential barriers to flu vaccine uptake (Table 3). Of these, “lack of recommendation by the doctor” was the highest-ranked (RI: 0.775), reported by 281 (51.5%) participants. The self-limiting nature of flu was ranked second (RI: 0.762), where 49.4% of participants responded that “flu is seasonal and will recover on its own”. Approximately half of the participants (50.3%) agreed with the statement “I believe that flu vaccine causes flu and fever” and ranked third (RI: 0.760). However, the lowest-ranked barrier was “vaccines are expensive,” and only 11.5% of participants agreed with it. Moreover, negative perceptions among participants were specifically assessed for their relationship with the vaccine uptake. The mean negative perception score was higher in those who did not receive the vaccine (5.17 ± 2.11; 68.5%).

Willingness to receive influenza vaccine

The mean willingness score among study participants was 3.54 ±  1.57 (Table 4). About one-third (n = 289, 36.6%) of study participants were willing to get vaccinated every year. However, the majority of the respondents (n = 545, 69%) were willing to receive the flu shot on their doctor’s recommendations, and 46.1% agreed to get the vaccine if provided free of cost at the university. The vaccine is available in intramuscular injection and intra-nasal spray dosage forms in various parts of the world. However, only the intramuscular route of the flu vaccine is available in Saudi Arabia. Surprisingly, most students (n = 496, 62.8%) were inclined to get a flu vaccination via intramuscular route compared to intra-nasal spray (n = 201, 25.4%). Willingness status was further stratified as vaccine acceptor (n = 289, 36.6%), vaccine rejecter (n = 131, 16.6%), and vaccine ambivalent (n = 370, 46.8%). Moreover, the majority (n = 277, 77.6%) of the non-vaccinated participants reported a poor level of willingness. However, half of the study population (n = 390, 49.4%) had a moderate level of willingness to receive the flu vaccine. There was a positive correlation (0.001*) between the knowledge and willingness score for the flu vaccine.

Determinants of influenza vaccine uptake

In Table 5, the majority of the population (n = 549, 69.5%) did not take the vaccine shot before winter. In binary analysis, age (22–25 years: OR: 0.730, p = 0.044), study field (non-health sciences: OR: 1.715, p = 0.001), poor knowledge score (OR: 2.021, p = 0.010), and poor willingness level (OR: 2.049, p <0.001) were found to be associated with reduced vaccine uptake. Adjusted regression analysis also identified similar factors associated with the reduced vaccine uptake.