Investigation of the influencing factors with the uptake of the COVID‐19 vaccine booster dose among the general population of Ardabil, Iran: A cross‐sectional study

Abstract Background and Aims Vaccination is one of the most efficient approaches to combating COVID‐19 if it is adequately embraced by the general population. Numerous factors influence the uptake or refusal of the booster dose. The goal of this study was to look at the different factors that affect how the general population in Ardabil feels about getting vaccine boosters (annual boosters) for COVID‐19 and to evaluate those feelings. Methods and Materials In the city of Ardabil, general population, perceptions towards the COVID‐19 vaccine booster (annual boosters) dose were evaluated using a cross‐sectional survey design between January 2 and March 25, 2022. A questionnaire was developed and filled out by 662 subjects via phone calls from healthcare providers. Descriptive statistics, the Chi‐square test, the correlation coefficient, and regression analysis were run for the analysis of quantitative data. Results The findings of the research revealed that 238 participants, or 35.9%, had previously gotten the booster dose of the COVID‐19 vaccination, while 198 participants, or 29.2%, expressed a desire to do so as soon as feasible. A total of 187 (28.2%) respondents reported not wanting to get a booster dose, and 39 (5.7%) could not decide. In the factors found to affect decisions not to accept regular doses, adverse effects (45.4%) and the presence of misinformation (30%) were the most important. Regression in educational achievement, and following the COVID‐19 news showed to be the major predictors of the subjects' attitudes toward the regular COVID‐19 vaccine. Conclusion The present findings revealed that low confidence in the efficiency of the booster shot and misinformation are two critical factors to consider in educational planning and interventions.


| INTRODUCTION
The coronavirus disease was originally caused by the SARS-CoV-2 virus, also known as COVID-19, which is an invasive condition. This infection was found for the first time in Wuhan, which is located in the Hubei region of China. From there, it moved on to other nations. 1,2 After a follow-up period of almost 2 years, it has become clear that adequate access to effective vaccinations and the adherence of health standards are essential to putting a stop to the COVID-19 outbreak and lowering the risk of severe illness and hospitalization. [3][4][5][6][7][8] The COVID-19 vaccines have proved efficient in dealing with major diseases, hospital stay, and mortality caused by affliction with various SARS-CoV-2strains. Antibody levels were used by the producers of COVID-19 vaccines as surrogate biomarkers to reveal the efficacy of vaccine. In fact, not unlike many vaccinations, the antibody levels of COVID-19 slowly decrease after vaccinations. [9][10][11][12][13] According to findings of a progressive reduction in illness after using the vaccine and the inhibitory role of the booster dose 6 months after the main vaccination, several more countries have agreed to administer a booster shot to people according to age categories. [14][15][16][17] Also The booster dose of the vaccine increases the antibody titer and reduces the chance of a widespread epidemic, and as a result, the number of severe patients and mortality decreases. 15,18 This decision was made based on the testimony of the steady reduction in contagion after using the vaccine. 8,[14][15][16] Because it only takes a few months for vaccination proficiency to fall from 74.7% to 53.1% in a survey of fully vaccinated people 2 several countries have begun administering booster doses by injection. 19,20 In the fight against the pandemic, the administration of booster injections will, at some point, prove to be a very important tactic. The majority of the authorities working in the various health care systems are concerned about how well a booster dosage will be received. 20 Overall, there is a consensus on the fat that those who got two doses of COVID-19 vaccines need to get later doses periodically. 21 These further doses have proved to be useful and safe. 2 In light of the fact that COVID-19 immunization attempts have been thwarted by false information, [22][23][24][25] it is expected that COVID-19 booster shot programs will meet similar obstacles. Studies of the reception of COVID-19 vaccine booster doses are scarce. A study showed that about 50% of qualified people were concerned about vaccination side effects that prevented them from receiving a booster dose, and 45.3% reckoned that getting a third dose of the vaccine could worsen the adverse effects. Concerns about getting vaccinated are not surprising. As an instance, the polio vaccination plan in Pakistan became troublesome due to public concern about the quality of the vaccine.
Another instance of vaccine hesitancy happened during an epidemic of influenza in America to convince pregnant women to get the vaccine. 24 Given that the decision to get a booster dose of the COVID-19 vaccine is the result of a complex interaction between different variables, it is hard to think of an unambiguousimage of potential perceptions of vaccination in the overall public. The present research explored factors that influence the uptake of the COVID-19 vaccine booster dose in the overall population of Ardabil (a historical city in the northwestern part of Iran, which is the capital of Ardabil Province).

| Design and setting of study
Between January 2 and March 25, 2022, research was done using a cross-sectional design. Six hundred sixty-two people in the city of Ardabil, ranging in age from 18 to 80 years, were asked to participate in this study. Using a web-based survey, the purpose of this study was an investigation of the influencing factors towards the uptake of the COVID-19 vaccine booster dose in the general public. Due to the fact that the government had ordered a lockdown, it was impossible to conduct a community-based nationwide sample poll. The sample size was estimated at 662 with a 95% confidence interval (CI), 0.5% margin of error, and a 25% expected agreement. The website Survey Monkey and the recruitment of participants relied on convenience (non-random) sampling.
Respondents from all throughout Ardabil city were sought for the research. The present researchers shared the survey link on social media (i.e., WhatsApp, Telegram channel) and via email with idividuals at the age of 20 and above (since, at the time of study, this age group were required to get the vaccine). The questionnaire for the study included sections on demographic and personal aspects connected to the COVID-19 vaccine booster (annual boosters). A total of 662 people were interviewed for this study. Inclusion criteria were that adults over the age of 18 were eligible to receive two doses of the vaccine, 6 months had passed since the injection of the last dose, and they expressed a willingness to participate.
Exclusion criteria were unwillingness to participate in the study, age under 18 years, and not receiving two doses of the vaccine.

| Survey instrument
Information required for this study was measured by asking the question: "Would you like to get a booster dose if you have one?" on a 4-point scale: 1 = No, never, 2 = No, but maybe in the future (as soon as), 3 = I cannot decide, 4 = I am already vaccinated.

| Independent variables
In this study, independent variables were segments of socioeconomic, demographic, and personal variables. These factors included gender, age, level of education, occupation, healthcare professionals, marital status, and the purpose for rejecting or postponing the booster shot. These reasons included (uncertainty about the effectiveness of the booster shot, the presence of side effects after getting the vaccine, the belief that the doses of vaccines taken give sufficient immunity, and the belief that the booster dose is unnecessary (incorrect or contradictory information).
Both closed and open-ended questions were used to collect sociodemographic information. In addition, individuals were questioned about their family's diagnosis of previous illnesses (diabetes, hyperlipidemia, lung disease, stroke, autoimmune disease, etc.).
Specialists in health education, psychiatry, and women's health checked that the survey was real and that it was true to its content.  This was used to judge how reliable the questions were. The validity of the instrument was tested in two ways: face validity and content validity, as substantiated by health education experts. The total content validity index in "relevance" of content, "simplicity," and "clarity," was, respectively, 82.6, 92.9, and 90.7. The reliability of the instrument was tested further using the internal consistency test (α = 0.83) as well as the test-retest reliability (r = 0.82).

| Analysis of statistics
The analysis was performed using the SPSS software (v.23). The data was reported scientifically as the mean, the standard deviation, and the percentages. The Pearson correlation coefficient was utilized to investigate the existence of a connection between numerical variables, while chi-square analysis was utilized to ascertain the nature of the link that existed between the ordinal variables that were being examined.
Regression was also used for predictive factors. In each of the tests, a threshold of significance of p less than 0.05 was adopted.

| Ethics approval and consent to participate
The present research was conducted in accordance with the Helsinki All participants were informed of the study, and just those who signed a written informed consent form were included in the study.

| Demographic and baseline characteristics
There were a total of 662 people who responded to the survey.
Among the 662 individuals who had been invited to take part in the research, 559 completed the questionnaire (response rate, 84.4% and 15% as the rate ofno response). In Table 1   Similar to this, other research found that the most prevalent reason given by people for their lack of desire to be vaccinated was a dearth of faith in the efficiency of booster shots and the difficulties that may arise from receiving them. 6 In another study, fear of complications from the vaccine was the fourth reason for reluctance to receive booster doses. 5 Thirty percent of individuals in the first 4 months of 2021 reported concern about possible complications. Therefore, they did not want to receive any vaccine against COVID-19. 22 Doubts about booster doses, followed by fear of complications, may be related to previous vaccine experiences.
Some people also found that booster doses could end up causing more severe complications than previous doses. 3 Another study found that 95.7% of 346 participants showed an increase in the titer of IgG antibodies on the tenth day after the vaccination booster. 23 The conduct of more research and the release of more findings were associated with an increased level of people's knowledge and a reduced rate of scepticism over vaccination. 24,27 Misinformation about immunizations was the second most common reason why people didn't want to get their shots renewed. Misinformation was one of the concerns of participants for vaccine acceptance in Tehran. 28 The widespread circulation of false stories on social media about the COVID-19 vaccinations has contributed to the spread of misinformation. 29 People with less money and more mental distress are more likely to have the wrong ideas about COVID-19. 19,29 The World Health Organization has taken steps to combat disinformation and misinformation, one of which is optimizing web searches to locate reputable and authoritative resources with answers to concerns concerning COVID-19 30 In addition to the publishing of warnings and notifications, as well as links to reputable sources, while looking for information regarding vaccinations. 31 Campaigns have been launched with the goals of providing accurate information and raising public awareness online, taking active actions against misinformation about the COVID-19 immunization, and increasing the number of people who get booster doses. 28 Although the efficacy of the vaccines in preventing the disease decreases over time, 21 it should be stated that this efficacy will undoubtedly provide more excellent protection against more severe COVID-19, hospitalization, and death. 32,33 Thus, to protect people and raise their safety against more severe complications of the diseases, policymakers are required to consider the prescription of extra boosters in the future.
Differences in demographic characteristics that affect people's attitudes, play a role in determining whether or not they are willing to take doses of the COVID-19 vaccination. 22,23 We found that a higher readiness to accept booster dosages occurred with increasing age. In addition, it was shown that those who suffer from chronic ailments have a stronger resistance to taking booster dosages. Other researchers found that people of older ages 21,22,28,34 and those with chronic conditions were more willing to get the COVID-19 vaccination dosages than the healthy ones. On the other hand, people with chronic illnesses have been shown to have results that don't fit with these findings. 34  It has been found that higher education levels are directly related to receiving booster doses. 16 Consistent with our findings, a higher percentage of respondents with academic degrees than those with high school or diploma degrees stated they were willing to have extra booster shots. However, this rate was not statistically significant.
Another study showed that the more education, the more acceptance of booster shots. 5 In another study, the vaccine acceptance rate was reduced in participants with higher levels of education. 20 Similar to Jørgensen's 37

ACKNOWLEDGMENTS
Hereby, the present researcher hope to be grateful to all the subjects participating in this study.

CONFLICT OF INTEREST STATEMENT
The authors declare no conflicts of interest.

DATA AVAILABILITY STATEMENT
The datasets using in the research can be available from the corresponding author on reasonable request.

ETHICS STATEMENT
The present research was conducted in accordance with the Helsinki Declaration. The ethical standards for scientific research procedures were adhered to. The Ethics Committee of the Ardabil University Medical Sciences (#IR.ARUMS.REC.1401.126) confirmed this study.
All participants were informed of the study, and just those who signed a written informed consent form were included in the study.
This consent was obtained as well from the authorities in chargetacitly or explicitly-at the institute/organization where the research was conducted, before the work was submitted for publication. The purpose of study was comprehensively explained to the subjects in the cover page of the questionnaire. The subjects were assured of the confidentiality of the information they provided. An informed consent was obtained from all participants to show agreement to take part in the study having reviewed the cover page of the questionnaire and clicking on the associated link. Moreover, for subjects below 18 years of age, the subject was asked for the consent of the parent or his/her guardian.

TRANSPARENCY STATEMENT
The lead author Arash Ziapour affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.