Health authorities have struggled to increase vaccination uptake since the COVID-19 vaccines became available. However, there have been increasing concerns about declining immunity after the initial COVID-19 vaccination with the emergence of new variants. Booster doses were implemented as a complementary policy to increase protection against COVID-19. Egyptian hemodialysis (HD) patients have shown a high rate of hesitancy to COVID-19 primary vaccination, yet their willingness to receive booster doses is unknown. This study aimed to assess COVID-19 vaccine booster hesitancy and its associated factors in Egyptian HD patients.A face-to-face interview was conducted with closed-ended questionnaires distributed to healthcare workers in seven Egyptian HD centers, mainly located in three Egyptian governorates, between the 7th of  March and the 7th of April 2022.n = 341) were willing to take the booster dose. The main reason for booster hesitancy was the opinion that a booster dose is unnecessary . Booster vaccine hesitancy was associated with female gender, younger age, being single, Alexandria and urban residency, the use of a tunneled dialysis catheter, not being fully vaccinated against COVID-19. Odds of booster hesitancy were higher among participants who did not receive full COVID-19 vaccination and among those who were not planning to take the influenza vaccine .Among 691 chronic HD patients, 49.3% (COVID-19 booster-dose hesitancy among HD patients in Egypt represents a major concern, is associated with vaccine hesitancy with respect to other vaccines and emphasizes the need to develop effective strategies to increase vaccine uptake.The online version contains supplementary material available at 10.1007/s40620-023-01586-z. On the 11th March, 2020, coronavirus disease 2019 (COVID-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was declared a pandemic by The World Health Organization (WHO) . It is cPatients on maintenance hemodialysis (HD) have a substantial risk of developing COVID-19. Such patients on HD typically have several medical comorbidities, including diabetes mellitus, obesity, and compromised immune system, all of which increase their risk of developing devastating COVID-19–related complications. One study found that the estimated 90-day mortality among COVID-19-infected HD patients exceeds 20% in the United States . There iNevertheless, several studies showed that a considerable proportion of patients on dialysis were reluctant to take the COVID-19 vaccines –15. Vari, Alexandria, and Fayoum. HD patients with dementia and those with language barriers that would impair basic comprehension of the questions were excluded. After obtaining informed consent from eligible patients, a healthcare worker belonging to each HD unit explained the aim of the questionnaire to each patient and fulfilled the related questions. The study was conducted between the 7th of both March and April 2022.This cross-sectional study recruited 691 chronic HD patients aged 18 years or above from seven different HD centers distributed mainly in three Egyptian governorates; DakahliaG*Power software was used for power analysis to enable sample size calculation in order to detect hypothesized effect , 18. UsiThe survey consisted of 27 questions with three major subheadings: demographic data (7 items), COVID-19 vaccine (10 items), and health of the responder and family (10 items). These subheadings followed the conceptual framework recommended by the Strategic Advisory Group of Experts on Immunization (SAGE) Working Group on Vaccine Hesitancy , 20, 21.The study protocol was reviewed and approved by the Mansoura University institutional research board with approval number: R.22.03.1639.P value < 0.05 was considered significant.The collected data were coded, processed and analyzed using Statistical Package for the Social Sciences (SPSS) program for Windows. Qualitative data were represented as frequencies and relative percentages. Chi-Square test was used to test the association between categorical variables. Binary logistic regression was utilized to test the association between independent and dependent variables. Subsequently, multivariate logistic regression was performed to compute the adjusted odds ratio (AOR) and 95% confidence interval (95% CI) for predictors of booster hesitancy. Among 692 chronic HD patients assessed for eligibility, 691 participants completed the survey , television , treating physician , and social media . Few patients  reported they had no information about COVID-19 vaccines. Of the studied patients, 486 (70.3%) were fully vaccinated against COVID-19. The most commonly received vaccine was Sinopharm , while Janssen / Johnson & Johnson was the least received vaccine . Table Participants of this study received information regarding COVID-19 vaccines mainly from dialysis staff , followed by safety uncertainties  and the side effects experienced after the previous doses . Unwillingness to receive the booster dose of the COVID-19 vaccine was significantly higher among females, those aged 18–30 years versus age above 50 years, single individuals, Alexandria and urban residents, dialysis via tunneled catheter, those who are not fully vaccinated, and vaccinated patients with moderate to severe side effects  were willing to take the booster dose, and the remaining 350 (50.7%) were booster-dose hesitant. The primary reason for hesitancy was the opinion that a booster dose is unnecessary  had no preference with regard to a specific vaccine. However, most participants who completed their initial regimen with AstraZeneca and BioNTech-Pfizer wished to receive a potential booster dose provided by the same manufacturer . In the case of Sinopharm, 46.4% (n = 52) of surveyed individuals were interested in receiving it as a booster dose, while in the case of Sinovac, 36.2% (n = 21) of subjects. The only patient who initially received Janssen / Johnson & Johnson vaccine and was willing to receive a booster dose preferred to receive the same vaccine.In general, 29.6% (101) of patients willing to receive a COVID-19 vaccine booster dose could not decide at the moment of the survey which vaccine to take, while 20.2% . The model correctly classified 71.8% of participants with 61.1% sensitivity and 82.7% specificity, and it explained 38.4% of the variance in booster hesitancy (Nagelkerke R2 = 0.384). Of the 10 predictor variables, only not being fully vaccinated and not planning a new flu shot were the two statistically significant independent predictors of the likelihood of booster hesitancy. Participants who did not receive full COVID-19 vaccination and those who were not planning to take the influenza vaccine had 10.8- and 4.2-times higher odds of exhibiting booster hesitancy, respectively.Table Convincing the Egyptian population to receive the COVID-19 vaccine has already been a challenging process. Despite good public knowledge and awareness about COVID-19 severity and vaccine safety , hesitanThe present study shows male predominance (58.9%) among our surveyed HD patients. This is in agreement with the latest published statistics from the Egyptian Renal Data System (ERDS) which shows a 58.7% male predominance in the Egyptian HD population . The majApproximately 57% of surveyed individuals lived in multigenerational housing, which represents an independent risk factor for COVID-19 infection . While dOnly about one-quarter of the participants in the present study reportedly became infected with SARS-CoV-2. This could be partly explained by the fact that some patients might have had asymptomatic COVID-19 infection as reported in previous studies –35. AnotVaccination practice, hesitancy, and acceptance are influenced by the source of information , especiaAs the Sinopharm vaccine against COVID-19 was the first vaccine to be approved in Egypt, it was the most commonly received one by participants of this survey with nearly one-third of surveyed individuals receiving the full vaccination schedule (2 doses of Sinopharm vaccine). Patients reported many reasons for not receiving the vaccine at all or not completing the full schedule. Reasons reported by the patients were classified into 5 main categories; their confidence (which represented 50%), complacency, convenience or constraints, risk calculation and collective responsibility for protection of others through herd immunity .The current study highlights an ongoing dilemma encountered since the beginning of the COVID-19 pandemic, it reflects frustration and indecisiveness regarding COVID-19 vaccines and the booster dose. About half of the participants (49.3%) exhibited their willingness to receive the booster dose of the COVID-19 vaccine. The majority of booster-hesitant individuals (44.9%) considered the booster dose unnecessary, while surprisingly only a minority were booster-hesitant owing to the side effects experienced after previous COVID-19 vaccine doses. This is in agreement with the Algerians  but contAlthough results obtained from surveys in developed countries were encouraging, with rates of willingness to receive vaccine boosters varying from 61.8 to 95.5% in the USA, Poland, Czech Republic, Germany, Japan, China, and Denmark , 41–47, Indeed, these dissimilarities among countries regarding COVID-19 vaccine hesitancy could be ascribed to differences in sociodemographic and anamnestic characteristics, human behavior, sources of information about vaccines, control of rumors and misinformation, trust in the health care systems, available vaccines, uncertainties about vaccine side effects, and belief in vaccine benefits. Surprisingly, the results of this study indicate that not only differences in the rate of booster hesitancy are evident among countries but also within the same country. Residents of Alexandria were more likely to be booster hesitant than their counterparts in other governorates included in this survey, a finding that could be attributed to the high frequency of patients without full primary vaccination against COVID-19 in Alexandria (∼47%) compared with Dakahlia and Fayoum . Similarly, urban residents constituted more than two-thirds of the not fully vaccinated participants.The present study showed that various social and demographic factors are significantly associated with vaccine booster hesitancy. Regarding gender, females were significantly more booster-dose hesitant than males . This finding is in accordance with findings from other studies about initial vaccination hesitancy , 51. ThiRegarding the age of the participants in the present study, older participants were more likely to accept vaccine boosters than younger ones. This finding seems to match other studies that were carried out addressing the initial COVID-19 vaccination not only in the dialysis population , 54 but Concerning marital status, single individuals who had never married were more likely to be booster-dose hesitant than married, divorced, or widowed individuals . This is in agreement with a study carried out in Saudi Arabia which demonstrated that married individuals were more likely to accept vaccination .Educational level has been a matter of debate as regards its correlation with vaccine hesitancy, with most studies reporting an inverse relationship between education and vaccine hesitancy , 48, 51,A striking finding in multivariate analysis in the current study is that participants who were already fully vaccinated against COVID-19 were nearly eleven times more likely to accept booster doses. This suggests that acceptance of primary vaccination is strongly associated with willingness to accept a booster dose once recommended. This finding is similar to that found in adult Americans .Concordance between the answers on the influenza vaccine and the COVID-19 vaccine booster dose deserves further discussion: although, as expected, not having received the influenza vaccine was associated with a significantly higher likelihood of COVID-19 vaccine booster-dose hesitancy , the prevalence of influenza vaccine hesitancy was greater compared with COVID-19 vaccine booster-dose hesitancy (∼75% versus ∼50%). Interestingly, those who were not planning or who had not yet decided whether to receive the influenza vaccine were more likely to be COVID-19 booster-hesitant in the multivariate analysis. This could be attributed to a lower perceived severity of seasonal influenza than COVID-19 by patients on dialysis  or lack The current study demonstrates that the participants’ preferences for a specific COVID-19 vaccine to be used as a booster dose did not necessarily match the previously administered vaccine. Surprisingly, nearly half of the participants willing to receive a COVID-19 booster dose did not specify any particular vaccine preference. They did not choose a specific vaccination or make a decision at the time of the survey. This finding is similar to that found in the Polish population, of whom ∼55% did not know which vaccine to receive as a booster dose or showed no preference for a specific vaccine. Although the highest level of vaccine agreement in the present study was seen for AstraZeneca, a low level of agreement was observed in surveyed participants in Poland and the authors attributed this finding to safety concerns and lower degree of trust in this vaccine perceived by the Polish population . On the This study provides significant insight into factors associated with COVID-19 vaccine booster hesitancy among Egyptian HD patients. To our knowledge, this is the first study to explore this issue. A notable strength of the study is that it is multicenter and the sample is representative of HD patients in three Egyptian Governorates. The questionnaire was completed by professional health care workers through face-to-face interviews, not web-based as in the case of most published literature, eliminating the idea of the presence of missing questions or data. Nevertheless, the study has several limitations. First, it is a cross-sectional study taking a snapshot of HD patients' willingness to take the booster vaccine, while in reality, individual attitudes are dynamic and evolving, and the intention to vaccinate is generally context-dependent. Second, as is the case for all cross-sectional studies, causality cannot be inferred from this design.Healthcare authorities in Egypt should be aware of the magnitude of the vaccine hesitancy problem among hemodialysis patients and act accordingly to resolve such a problem. The results of the current study could be used to identify solutions to the vaccine hesitancy problem. Focusing on the younger generations, female gender, unmarried, and unvaccinated patients to raise their awareness and fight back against false information is mandatory to decrease vaccine hesitancy. Since healthcare workers played a critical role in the delivery of information to the participants of the present study, they should raise awareness regarding the general attitude toward vaccination focusing on the importance of vaccination and the safety and efficacy of the available vaccines. Another effective strategy for reducing booster hesitancy, particularly for in-center HD patients, is the provision of COVID-19 vaccination as a component of routine in-center care which significantly reduced the odds of vaccine hesitancy in South Africa .COVID-19 booster-dose hesitancy is highly prevalent among hemodialysis patients in Egypt. Health authorities should invest in health promotion to disseminate the right medical information to improve vaccine uptake.Supplementary file1 (DOCX 24 KB)Below is the link to the electronic supplementary material.


The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is evolving,the newly emerged Omicron variant being the dominant strain worldwide, and this has raised concerns about vaccine efficacy. The purposes of this survey were to examine the extent to which healthcare workers (HCWs) intend to receive a second booster dose of the COVID-19 vaccine and the factors that influence their willingness to accept it.The study was conducted among HCWs who were randomly selected from four public hospitals in the Campania region, Southern Italy.A total of 496 HCWs answered the questionnaire (a response rate of 61.2%). Among the respondents, 20.8% indicated a score of 10, using a 10-point Likert-type scale, regarding the usefulness of a second COVID-19 vaccine booster dose. Physicians, HCWs who believed that COVID-19 was a severe disease, and those who have acquired information about the second booster dose from scientific journals were more likely to have this positive attitude. Slightly more than half of HCWs self-reported willingness to receive a second booster dose. Respondents who believe that HCWs are at higher risk of being infected by SARS-CoV-2, those who have a higher belief that COVID-19 is a severe disease, and those who have a higher belief that a second booster dose is useful were more willing to receive a second booster dose. The main reasons for those who had a positive intention were to protect their family members and patients, whereas, the main reasons for not getting vaccinated or for uncertainty were that the dose does not offer protection against the emerging variants and the fear of its side effects. HCWs of younger age, physicians, those who have a higher belief that a second booster dose is useful, and those who were willing to receive a second booster dose were more likely to recommend the booster dose to their patients.This study's findings highlight the necessity for designing and implementing educational interventions for improving second booster dose uptake and beliefs among HCWs and their capacity to recommend the vaccine to the patients. The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has generated more than half a billion confirmed cases and almost 6.5 million deaths around the world , 4, and From this point of view, it is, therefore, extremely important and crucial to understand and assess HCWs' willingness to have the second booster dose of the COVID-19 vaccine; no literature is available on this topic. Therefore, the purposes of this present survey were to examine the extent to which a large sample of HCWs in Italy intends to receive a second booster dose of the COVID-19 vaccine and the factors that influence their willingness for accepting it.The study was carried out from 12 July to 9 September 2022. The source population included all 4,000 HCWs who worked in different wards in four randomly selected public hospitals, one teaching and three nonteaching, located in the Campania region, Southern Italy. The sample for the present study included 496 HCWs who had been selected by a simple random sampling technique. A sample size of 384 HCWs was estimated assuming that 50% of the study population would intend to receive a second booster of the COVID-19 vaccine, 95% confidence interval, and a margin of error of 5%.Initially, the research team asked for permission from the health director of each hospital to conduct the study. After the approval, the team identified in each ward an HCW to distribute the questionnaire to the HCWs who were randomly selected from the list of those present at that moment in each ward and to collect the filled questionnaires within an envelope to maintain anonymity and to return the envelope. The questionnaire contained a brief introduction about the objectives, procedure, confidentiality, and anonymity of the survey, that the participation was voluntary, that the information provided will be used only for research purposes, and that the participant was able to withdraw at any moment. HCWs gave their informed consent to participate by handing in the questionnaire. The participants received no incentive to complete the questionnaire.All data were collected through a self-administered questionnaire adopted and modified from previously published studies of the research group –20. The Ethical approval of the study protocol and questionnaire was received from the Ethics Committee of the Teaching Hospital of the University of Campania “Luigi Vanvitelli.”t-test, to evaluate predictors of the different outcomes of interest. Only those variables with a p < 0.25 in the univariate analysis were entered into three multivariate logistic regression models to assess associations between the main dependent variables and the several independent variables. Then, multivariate logistic regression analysis with backward elimination of any variable that did not contribute to the model on the grounds of the Likelihood Ratio test (cut-off at p = 0.05) was performed. Variables whose exclusion altered the coefficient of the remaining variables were kept in the model. Backward stepwise selection has been used with a threshold of p = 0.2 and p = 0.4, respectively, for the entry or removal of the variables from the final models. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were calculated in the models. Three outcomes of interest have been identified: a) belief that a second booster dose of the COVID-19 vaccine was useful  (Model 1); b) willingness to receive a second booster dose of the COVID-19 vaccine  (Model 2); c) recommendation of a second booster dose of the COVID-19 vaccine to the patients  (Model 3). The following potential determinants were included in all models: gender ; age, in years (continuous); marital status ; physicians ; length of practice, in years ; having worked in a COVID-19 ward ; having underlying at least one chronic medical condition ; having been tested positive for COVID-19 ; at least one family member/colleague/friend who had been tested positive for COVID-19 ; perceived risk of getting infected with SARS-CoV-2 during the working activity ; belief that COVID-19 is a serious disease ; belief that HCWs are at a higher risk of being infected by SARS-CoV-2 ; scientific journals as source of information about the second booster dose of the COVID-19 vaccine ; and needing additional information regarding the second booster dose of the COVID-19 vaccine . Moreover, the variables belief that the second booster dose of the COVID-19 vaccine was useful  and belief that the second booster dose of the COVID-19 vaccine was effective  were included in Models 2 and 3; and the variable willingness to receive the second booster dose of the COVID-19 vaccine  was included in Model 3. For all analyses, two-tailed tests were used and statistical significance was determined with a p-value equal to or less than 0.05.All statistical analyses were conducted using the software STATA version 15.1. Descriptive statistics were used with frequency, mean, and standard deviation to describe the principal characteristics of the participants, as well as behavior and attitude toward having a second COVID-19 booster dose. Multiple logistic regression models were built using the strategy suggested by Hosmer et al. . Each vaA total of 496 HCWs, out of the 810 selected, answered the questionnaire with a response rate of 61.2%. The main sociodemographic, general, and professional characteristics of the respondents are summarized in The results regarding the attitudes, measured on a 10-point Likert-type scale, showed that the mean scores of the respondent's belief that COVID-19 was a severe disease and whether they feel at risk of being infected by SARS-CoV-2 during the working activity were 7.4 and 6.8, respectively, with 19.6% believing themselves to be at an elevated risk . The mean scores regarding the usefulness and efficacy of a second booster dose of the COVID-19 vaccine were 6.7 and 6, respectively, with only 20.8% and 16.4% of participants who had indicated a score of 10. Among those respondents who had not had the second booster dose of the COVID-19 vaccine, 52.6% self-reported a willingness to receive it, and 25.1% and 22.3% indicated that they had “no intention” or showed “uncertainty.” The main self-reported reasons for those who had a positive intention were to protect their family members (49.6%) and their patients (42.9%) and the fear of acquiring the infection (37.6%). The main reasons for not getting vaccinated or for uncertainty, however, were that the dose does not offer protection against the emerging variants (54.6%) and the fear of its side effects (27%). Three variables were found to be associated with the HCWs' willingness to receive a second booster dose in the multivariate logistic regression analysis. Respondents who believed that HCWs are at higher risk of being infected by SARS-CoV-2 , those who have a higher belief that COVID-19 was a severe disease , and those who have a higher belief that a second booster dose is useful  were more willing to receive a second booster dose of the COVID-19 vaccine . The internet (51.8%), mass media (48.6%), scientific meetings (48.2%), and scientific journals (41.5%) were indicated as primary sources for this information, followed by social networks (26.7%). More than one-third of the respondents expressed an interest in acquiring additional information about the second booster dose (36.3%).To our knowledge, this is the largest survey of HCWs' willingness to have a second booster dose of the COVID-19 vaccine and the factors associated with this decision conducted in Italy. The major findings can be summarized in the following five points. First, slightly more than 50% of the sample would accept a second booster dose of the COVID-19 vaccine. Second, the main reasons behind the willingness to have a second booster dose were to protect family members and patients. Third, the main reasons for the intention to not receive or uncertainty toward the second booster dose were the belief that it does not offer protection against the emerging variants and the fear of side effects. Fourth, scientific meetings and journals were among the primary sources of information on the second booster dose. Fifth, several determinants have been observed to be significantly associated with the different outcomes of interest.Overall, the present survey revealed that only 52.6% of respondents self-reported a willingness to receive a second booster dose. Though it is only mandatory for HCWs to have the first COVID-19 booster dose, it was nonetheless a striking and unexpected finding that very few (48.1%) eligible HCWs had received a second booster dose. The prevalence of this willingness was lower than the values observed among HCWs in Saudi Arabia (55.3%) , CzechiaThis study highlighted that the protection of their family members and patients and the fear of acquiring the infection were the most frequent reasons for the willingness to receive a second booster dose of the COVID-19 vaccine. These findings are consistent with other recent similar research studies –38. A poThe results of the multivariate logistic regression analysis showed that several factors were significant predictors of attitude, vaccine willingness, and vaccine recommendation. Of the several sociodemographic and professional characteristics, only age and professional role were associated with the outcomes of interest. Indeed, physicians indicated a higher score regarding the usefulness of a second booster dose of the COVID-19 vaccine, and as, those younger, they were more likely to recommend this booster dose to the patients and more willing to receive it. Moreover, three variables related to the respondents' attitudes have had a significant impact. HCWs who believed that COVID-19 was a serious disease and who believed that they are at higher risk of being infected by SARS-CoV-2 were more likely to believe that the second booster dose is useful and more willing to receive the booster dose, and HCWs who believed that the second booster dose is useful and who were willing to receive it were more likely to recommend the booster dose to the patients. Therefore, it is extremely important that the HCWs should be aware of the vaccine's effectiveness in preventing SARS-CoV-2 infection and to improve their attitudes as an effective way to enhance HCWs' willingness to be vaccinated with a second booster dose of the COVID-19 vaccine or to recommend it. Some of these associations have been observed in a previous investigation .This present survey showed that almost all HCWs had received information related to a second booster dose of the COVID-19 vaccine, with scientific meetings and journals being two of the most trusted sources. It is important to highlight that scientific journals have a significant effect on the higher belief regarding the usefulness of a second booster dose. This finding confirms that these sources are an important factor in the vaccination process and decision. Indeed, this association is in accordance with previous studies that showed that scientific journals played a significant role in determining a higher level of knowledge, a more positive attitude, an increase in the willingness to receive a vaccine, and a higher vaccination coverage among those who have acquired information from these sources , 18. MorThe results from the present survey should also be considered with some potential methodological limitations. First, as in all cross-sectional studies, no causal relationships between the independent variables and the different outcomes of interest can be established. Second, the survey was administered to HCWs in a single geographic area, and therefore, the findings may not necessarily apply to other areas of Italy. Third, a self-reporting questionnaire may have introduced social desirability bias and the surveyed HCWs may tend to have more positive attitudes that lead to an overestimation of their intention to have a second booster dose of the COVID-19 vaccine. However, an anonymous questionnaire has been used to reduce this bias. Despite these limitations, this study was the first to assess the willingness to have a second booster dose among HCWs in Italy, and it thus provides an important picture with important implications for health policymakers.In conclusion, this survey reveals a low willingness to receive a second booster dose, the facilitators and barriers influencing this willingness, and the factors associated with this choice. The findings have important implications and highlight the necessity for designing and implementing targeted education interventions for improving the second booster dose of the COVID-19 vaccine uptake among HCWs and their capacity to recommend the vaccine to the patients. In the future, investigations are expected to quantify the coverage level in HCWs and to evaluate whether they can promote this vaccination with special attention toward more vulnerable people.Walter Longanella , Mario Massimo Mensorio , Federica Cantore .The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.The studies involving human participants were reviewed and approved by Teaching Hospital of the University of Campania Luigi Vanvitelli. The patients/participants provided their written informed consent to participate in this study.GDP, GMdG, LF, and AN participated in the conception and design of the study and contributed to the data collection, data analysis, and interpretation. IFA the principal investigator, designed the study, was responsible for the statistical analysis and interpretation, drafted and wrote the article. All authors have read and approved the final version of the article and agree to be accountable for all aspects of the work.


Backgroundand objectives: Although several vaccines have been produced and administered around the world, new SARS-CoV-2 worsened the COVID-19 infection risk and impacted the initial vaccine dosage effectiveness. Based on studies indicating that the third and fourth COVID-19 vaccine doses significantly reduced COVID-19 transmission, Saudi Arabia has been administering COVID-19 booster vaccine doses to its citizens. The purpose of this study was to evaluate the uptake of the COVID-19 vaccine booster in relation to the socio-demographic characteristics and other associated factors among the Saudi population. Materials and Methods: This study was an online analytical cross-sectional study using a self-administered questionnaire. Pearson Chi-square test and multiple logistic regression analyses were used to determine factors associated with the uptake of COVID-19 booster dose vaccines. Results: A total of 2332 responded to our study. Overall, 527 (22.6%) participants had received a booster dose. An age of 55 and above , Eastern region , history of influenza vaccination at annual intervals , the first dose of Moderna vaccine , and cancer  were independent factors most associated with a higher uptake of the COVID-19 vaccine booster dose. In contrast, the second dose of Moderna vaccine , AstraZeneca vaccine , strong symptoms from side effects after the second dose of the COVID-19 vaccine  were independent factors most associated with a lower uptake of the COVID-19 vaccine booster dose. Conclusions: Our findings indicate low COVID-19 vaccine booster uptake. This necessitates the need for strategies to address discouraging factors of the COVID-19 vaccine booster dose uptake and engage the Saudi population to raise awareness about the importance of the booster dose. In December 2019, cases of atypical pneumonia due to an unknown cause were reported to the World Health Organization (WHO) from Wuhan, China . SeveralImmunization experts have carefully considered whether COVID-19 booster doses for specific susceptible groups or everyone are necessary to bolster immunity in order to combat the newly emerging strains of COVID-19 and there is uncertainty about the duration of protection offered by the vaccines . As publA study at Ajman University showed that the average knowledge score was 44.6% for the third COVID-19 booster dose, but the attitude score was 70.2% . In thisWe conducted a cross-sectional study from December 2021 to March 2022. All adults aged 18 years and older who were vaccinated against COVID-19 and had taken the vaccine booster dose were eligible for this study. We used an anonymous and self-administered questionnaire designed following the examples of previous similar studies assessing COVID-19 vaccine acceptance and uptake ,14,15,16The uptake of the COVID-19 vaccine booster dose was our study outcome variable. Participants were asked if they had received the vaccine booster dose and had to answer YES or NO.The age variable was categorized into: 18–25, 26–35, 36–45, 46–54, and 55 and above years. Gender was binary: male or female, as was marital status: married or single. Residence was divided in five regions: Northern, Southern, Western, Eastern, and Central. Education level was divided into four levels: below secondary school, secondary school, bachelor’s, and postgraduate degrees. Employment status, healthcare work employment type, obesity status, and smoking were dichotomous, and responses were YES or NO. Monthly income in Saudi Riyal (SAR) was grouped into 3 categories: less than SAR 5000, SAR 5000–10,000, and more than SAR 10,000.Participants were asked about vaccination history. Answering a question about influenza vaccine, they had to choose from “never got before”,” in irregular intervals”, or “annual intervals”. Answering a question about the first or second dose of COVID-19 vaccine, they had to choose from “Pfizer”, “Moderna”, “Oxford AstraZeneca”, or “other”. The respondents were asked if they contracted COVID-19 infection and had to answer YES or NO. Regarding when they got COVID-19 in relation to vaccination, they had to choose from “before the first dose”, “after the first dose”, or “after the second dose”.Vaccine side effect symptoms or COVID-19 symptoms experienced were grouped into: no symptoms, mild symptoms , moderate symptoms (symptoms needing treatment taken at home), strong symptoms , and critical (ICU admission). Then, participants were asked to list the symptoms experienced.On a three-point Likert scale , participants gave answers to statements about their trust in vaccines, healthcare professionals, public health and government institutions, different reasons for them to get COVID-19 vaccines, preventive recommendations, and keeping up with new COVID-19 information.Participants were asked about chronic diseases, and they had to mention which chronic disease they had if they responded “Yes”. Finally, to know about the sources of COVID-19 information, participants were asked to list their most common sources of information about COVID-19 and its vaccines.p value less than 0.05 was statistically significant. A descriptive analysis based on the frequency and percent distribution was conducted for all variables. Crosstabulation was used to compare the intention to take up COVID-19 vaccine booster dose among variables and groups. Relationships between variables were tested using Pearson Chi-square test and an exact probability test for small frequency distributions. Subsequently, all variables with a statistically significant association with the dependent variable (received booster dose) were included in the multiple predictive models based on the backward stepwise method with a p-value of <0.05 as an entry criterion and a p-value of >0.05 as an exclusion criterion. Multiple logistic regression analyses were used to estimate adjusted odds ratios (aOR) and their 95% confidence intervals (95% CI) for the association of getting the COVID-19 booster dose with the predictors.Data were extracted, revised, coded, and entered into IBM SPSS version 22  statistical software. All statistical analysis was done using two-tailed tests, and a The Research Ethics Committee at Security Forces Hospital Program in Holy Capital (HAP-02-K-052) reviewed and approved this research project being conducted. The approval number is ECM#0460-190122.A total of 2332 people participated in this study. Of all the participants, the majority (49.1%) were aged 18–25 years, were not obese (88.0%), and 51% were males. Most (61.4%) were not married, had a bachelor’s degree (70.8%), and were not employed (57.7%). Most employed participants (14.5%) worked outside the healthcare sector (85.5%). Of all the participants, the majority (57.6%) earned less than SAR 5000 monthly (57.6%), lived in the Central region (39.0%), and were nonsmokers (81.9%) .p < 0.01) got vaccinated more with the booster dose (47.5%) than those aged 18–25 years (13.9%) despite the latter being the most predominant age group. More males (26.5%) significantly received the booster dose (p < 0.01) than females (18.5%). Being married was associated with almost double take-ups of the booster dose (30.1%) (p < 0.01) than being single (17.5%). The booster dose was received significantly more by participants in the Eastern region (33.6%) (p < 0.01). A higher education level was associated with more booster doses, with those with postgraduate degrees (41.3%) (p < 0.01) receiving significantly more booster doses. The COVID-19 vaccine booster dose was received significantly more by healthcare workers (p < 0.01) and employed participants (p < 0.01) in general . Taking up the booster dose significantly increased with the increase in monthly income (p < 0.01). Those who earned more than SAR 10,000 were more than twice as likely to receive the booster dose than those who earned less than SAR 5000 (34.8% vs. 15.6%). Obese participants and smokers were also significantly more likely to take up the booster dose (p < 0.01).Overall, 527 (22.6%) participants had received the booster dose. Older age was associated with a higher uptake of the COVID-19 booster vaccine, which increased with age. Those aged 55 years and more significantly (p < 0.01). Participants who took influenza on an annual basis had a higher booster dose uptake rate (38.6%). The types of the vaccine on the first dose (p < 0.01) and the second dose (p = 0.002) were significantly associated with the uptake of the booster dose. Participants who took the first or second doses of the Moderna COVID-19 vaccines had the lowest booster dose uptake rates . However, 71.8% and 77.4% received Pfizer vaccines as the first and second doses, respectively. Experiencing side effects on the second dose (p < 0.01), being infected with COVID-19 (p = 0.006), COVID-19 symptom severity (p < 0.01), having COVID-19 after receiving both doses (p < 0.01), and types of symptoms experienced (p = 0.028) were significantly associated with lower COVID-19 booster dose uptake. Participants who reported experiencing adverse effects following their second doses, and those who faced critical symptoms (admitted to ICU) were the least vaccinated with booster doses . However, the difference was not statistically significant for the first dose receivers (p = 0.34).Regarding COVID-19 and infection vaccination history, participants with a history of previous influenza vaccines were significantly more likely to take up the COVID-19 vaccine booster dose  . In termp < 0.01). However, practicing preventive measures and following up with COVID-19 news did not substantially impact the booster uptake (p > 0.05) , WHO (85.3%), healthcare practitioners (82.1%), the effectiveness of all vaccines (85.7%), COVID-19 vaccines (84.3%), and were not satisfied with the previous COVID-19 vaccine doses taken (84.2%). Overall, loss of trust in healthcare and public health professionals and institutions was significantly associated with less booster uptake ( > 0.05) .Having comorbidities (n = 501) was significantly associated with booster uptake (p < 0.01), with the most uptake (53.8%) in cancer patients, while the least was in patients with immune deficiency diseases .p < 0.05)  .Participants aged 55 and above were three times more likely to get a booster dose than those aged 26–35 years . Living in other regions other than the East and West were not significantly associated with the booster dose uptake. However, living in the East was almost two times more associated with the booster dose uptake . Influenza vaccination at annual intervals was two times more associated with more vaccine booster doses  than irregular influenza vaccination. Although the first dose of the Moderna vaccine was associated with more booster dose uptake , the second dose of the Moderna vaccine was associated with about 21% less booster dose uptake , while the second dose of AstraZeneca vaccine was associated with 30% less booster dose uptake . On the other hand, participants who did not lose or have faith in COVID-19 were also more likely to get booster doses . Participants who had cancer were two times more likely to get booster vaccine doses than those without cancer .Even if it is expected that the worse their side effect symptoms are, the less people are less likely to take up the booster dose, participants who experienced critical symptoms were 19% less likely to get a booster dose , while those with strong and moderate symptoms were 39%  and 29%  less likely to get a booster dose, respectively. Other variables analyzed were not statistically significant predictors.p = 0.000). However, those who followed scientifically developed resources, such as articles, health practitioners, the WHO, and the Ministry of Health, had the highest uptake of booster doses. In contrast, those who got information from social media, celebrities, influencers, friends, and family had the lowest COVID-19 vaccine booster uptake , and uptake of the COVID-19 booster dose increased as the education levels increased. This can be explained by the fact that most high-income earners are leaders in different sectors who had to be exemplary to other workers by getting vaccinated earlier, which made them qualify for a booster dose earlier too. That is also in line with education’s impact on the take up of the COVID-19 booster dose. Highly educated people usually occupy high-income job positions and are more likely to be better informed on vaccines as their sources of information are more likely to be genuine, such as scientific papers and healthcare and public health professionals’ contacts. Some studies have reported similar findings as ours, and in addition, it has been reported that higher education institutions were more likely to impose vaccine mandates . This miMore participants who had obesity and who were smokers received booster doses than others. COVID-19 was found to be more severe in individuals with chronic conditions and obesity, and the COVID-19 vaccine booster dose is recommended more in people with comorbidities. Obesity and smoking are known risk factors for most chronic diseases, and most participants who were smokers might have other chronic diseases. Therefore, these conditions might have encouraged them to receive the booster doses .Our findings also indicated that the majority of the participants received Pfizer vaccines, followed by Oxford AstraZeneca. The efficacy of these two vaccines is believed to be the same with similar side effects. In Saudi Arabia, Pfizer vaccines were distributed more than any other vaccine type. Generally, the Pfizer and AstraZeneca vaccine side effects were mostly mild. We found a decrease in side effects as the severity increased for Pfizer and AstraZeneca vaccines, with more severe side effects reported after the second dose. Side effects for Moderna vaccines were mostly the same throughout. Previous studies have reported reduced side effects for the Pfizer vaccine compared to Moderna vaccines . On the A history of taking annual influenza vaccine was associated with a high uptake of COVID-19 booster vaccines. This might be because participants who take regular influenza vaccines are well informed about vaccines and perceive them as safe since they are used to them. In a study carried out in the UAE, they found similar influenza vaccine uptake as a factor for acceptance of COVID-19 vaccines .We found that participants who had COVID-19 infection after receiving a double dose of COVID-19 and who reported critical symptoms were the least vaccinated with booster doses. Several studies have shown that COVID-19 vaccines reduce the likelihood of infection and COVID-19 severity ,16,25. BThis study showed that adverse effect symptoms significantly influence the booster uptake, with shortness of breath being associated with the highest booster uptake rate, followed by anosmia, myalgia, and fatigue. These findings are similar to what was found in a study conducted by Meo et al. , who fouOverall, loss of trust in healthcare and public health professionals and institutions was significantly associated with less booster uptake. This might be caused by the frequent changes in the scientific information that comes out as science uncovers more about COVID-19, which can lead to mistrust in science, scientists, scientific institutions, and healthcare professionals and institutions. Most participants who did not receive a booster dose were not satisfied with the previous COVID-19 vaccine doses taken and lost trust in the Saudi Ministry of Health, WHO, healthcare practitioners, and the effectiveness of all vaccines. This can be explained by the possibility of reinfection after being fully vaccinated, which is contrary to what they thought before taking vaccines when they thought that it was completely protective against COVID-19. Strategies to approach them, more education programs focusing on different reasons why vaccines are not 100% protective, such as the new variants, and the effectiveness percentage of each vaccine, as well as education on the importance of a booster dose and COVID-19 vaccination in general, are needed. Our findings are also supported by other previous studies indicating that mistrust of science and health institutions could impede preventive measures and vaccination ,28. ThisComorbidities, such as diabetes, hypertension, cancer, respiratory disease, asthma, and renal and immunodeficiency diseases, were positively correlated with receiving booster doses. Cancer was associated with the highest booster vaccine uptake, followed by diabetes. People with chronic diseases have been encouraged to get vaccinated to lower their increased risk of mortality and morbidity from COVID-19, and it was found that people with higher perceived risks demonstrated lower vaccination hesitancy . This miVaccinated people have been gradually increasing as time goes on. In Saudi Arabia, data indicate that less than 5% of people were fully vaccinated in July 2021 . HoweverMultiple logistic regression analysis showed that age, residence region, being employed, previous influenza vaccination, type of COVID-19 vaccine received, side effect strong symptoms, faith in COVID-19 vaccine and having cancer remained significant independent predictors of COVID-19 vaccine booster dose uptake. This confirms that these factors had strong associations with the uptake of COVID-19 booster vaccine doses. These results are similar to comparative results we discussed above. However, logistic regression showed that participants who regularly tool influenza vaccine were two times more likely to take up COVID-19 booster doses than the ones who tool it irregularly. This is expected since people with a history of irregularities are more likely to keep up with COVID-19 vaccination schedules. Living in the Eastern region was two times more associated with the booster uptake than living in the Western region. The first cases of COVID-19 in Saudi Arabia were discovered in the East, which might have led to more efforts to combat the pandemic and more awareness among the residents and subsequently more and earlier uptake of vaccines . The earWe found that participants who followed scientifically developed resources such as scientific articles, health practitioners, the WHO, and the Ministry of Health had a higher uptake of booster doses compared to those who got information from social media, celebrities, influencers, friends, and family. This indicates that trusted sources of COVID-19 information are scientific articles, health practitioners, the WHO, and the Ministry of Health. Previous studies have indicated that social media and other unofficial sources of information were associated with more conspiracy theories about COVID-19 and vaccines, which could explain the lower uptake rates among participants who use them as their sources of information ,31. ZhanThe quantitative study design used limited the exploration of some aspects in detail, rather than in a structured format. A qualitative study design alongside the quantitative one would generate more information about COVID-19 vaccine booster doses. The convenience sampling method and online nature of this study cause under- or over-representation of the Saudi population and are prone to bias. Therefore, extensive experimental or longitudinal studies would mitigate these limitations. Since more people are becoming eligible for a vaccination with the COVID-19 vaccine booster dose every day, the results presented in this study might not accurately represent the current situation. We recommend further studies to remain up to date.This study showed that older age, male gender, being married, higher education levels, high income, previous influenza vaccine, having comorbidities, consulting the Ministry of Health, the WHO, healthcare professions, and scientific articles as sources of information were associated with a high uptake of the COVID-19 booster dose. In contrast, being vaccinated with Moderna COVID-19 vaccines, experiencing side effects on the second dose and critical symptoms, infection with COVID-19 after full vaccination, and loss of trust in healthcare, public health professionals and institution, and using social media, celebrities, influencers, friends, and family as sources of information were associated with a lower uptake of the COVID-19 booster vaccines. We recommend healthcare organizations, the government, and other authorities design strategies that augment the public’s knowledge, awareness, perception, and debunk myths about the COVID-19 vaccine booster dose. Extensive longitudinal and offline studies with larger samples are also recommended to explore, in detail, the booster dose uptake.


A second COVID-19 vaccine booster dose is effective and safe for older adults. This study investigated hesitancy to take up a second COVID-19 vaccine booster dose and its determinants among older adults in Hong Kong. Participants were Chinese-speaking community-dwelling adults aged 65 years or above. Telephone numbers were randomly selected from up-to-date telephone directories. A total of 370 participants completed the telephone survey. Logistic regression models were fitted for data analysis. Among the participants, half (52.4%) were hesitant to receive the second COVID-19 vaccine booster dose. After adjustment for significant background characteristics, perceived benefits , cues to action , and perceived self-efficacy  of receiving the second booster dose were associated with lower vaccine hesitancy. Perceived barriers  and vaccine fatigue (tired of receiving repeated COVID-19 vaccination)  were associated with higher vaccine hesitancy. Level of hesitancy to receive the second booster dose was high among older adults in Hong Kong. Health authorities should address vaccine fatigue and modify perceptions related to the second booster dose. Globally, the ongoing pandemic of coronavirus disease 2019 (COVID-19) is still a severe public health issue. As of 12 December 2022, there have been 646 million confirmed cases and 6.6 million deaths caused by COVID-19 worldwide . The majCOVID-19 vaccination is one of the most cost-effective measures to control the pandemic. It is proven to be effective and safe in preventing deaths and other severe consequences caused by COVID-19 among older adults ,5,6. HowA second booster dose could help increase protection levels, especially for individuals in high-risk groups, such as older adults. Numerous studies demonstrated that a second booster dose was effective in reducing the risk of COVID-19-related outcomes , such as polymerase chain reaction-confirmed infection, symptomatic infection, severe illness, hospitalization, emergency department and urgent care counters and deaths ,16,17,18Based on the vaccine effectiveness and safety of receiving the second COVID-19 vaccine booster dose, on 18 August 2022, the World Health Organization (WHO) issued a practice statement and recommended countries consider a second COVID-19 vaccine booster dose in the populations at risk, including older people . Health Despite the promising evidence of COVID-19 vaccine effectiveness and safety, vaccine hesitancy is still a significant threat to the rollout of COVID-19 vaccine booster doses. Previous studies showed that older adults were less willing to receive the primary COVID-19 vaccination series and first booster dose than the younger groups in China ,30,31,32Vaccine fatigue refers to people’s inaction toward vaccine instructions due to perceived burden and burnout . The neeCOVID-19 vaccinations and booster doses are hot topics on different media. Exposure to information related to COVID-19 vaccination influenced people’s decision to take up such vaccines. The general population in China with a higher frequency of exposure to positive information supporting COVID-19 vaccination were more likely to complete the primary vaccination series . It is pIt is essential to understand vaccine hesitancy to receive the second COVID-19 booster dose and its associated factors among older adults in order to design effective health promotion strategies. However, there is a dearth of studies investigating the hesitancy to receive the second booster dose among older adults. To address the knowledge gaps, this study investigated the vaccine hesitancy to receive the second COVID-19 vaccine booster dose among older adults in Hong Kong, China. In addition, we examined the factors associated with the vaccine hesitancy to receive the second booster dose.We conducted a random telephone survey among community-dwelling Chinese-speaking adults aged 65 years or above in Hong Kong between 11 May 2022 and 11 July 2022. The number of local daily-confirmed COVID-19 cases was 254 on 11 May 2022 and slowly increased to 2558 on 11 July 2022. The COVID-19 situation in Hong Kong during the study period is illustrated in The inclusion criteria of the participants were: (1) community-dwelling Chinese-speaking individuals aged 65 years or above, and (2) having a Hong Kong ID card. Those who were not able to communicate effectively with the study interviewers were excluded.Simple random sampling was used. All the household telephone numbers  listed on the up-to-date telephone directories in Hong Kong were inputted into an Excel sheet. Using the random selection function in the software, about 4000 telephone numbers were randomly selected. Experienced interviewers conducted the telephone interview during 6:00–10:00 p.m. on weekdays and 2:00–9:00 p.m. on Saturdays to prevent under-sampling of individuals who worked on weekdays. Each number was called up to 5 times at different timeslots. Households were regarded as “non-valid”  if no one answered the call after five times of calling. To avoid clustering effects, if there was more than one individual in a household aged 65 or more, the one with a birthday closest to the survey date was invited to join the study. Interviewers screened the eligibility of prospective participants and provided a study briefing to participants. Verbal informed consent was obtained from all participants. Prior to the interview, the interviewers used a checklist to confirm that the participant was fully informed about the study. There were six parts on the checklist: (1) questions to confirm eligibility, (2) scrips about study information, (3) the interviewers confirming they had introduced the research purpose, research process, main content of the survey, time required for completing the survey, rights of the participant, that non-participation would not affect the use of any services, and confidentiality of the research data, (4) the interviewers confirming that the participant fully understood the above contents, (5) the interviewers confirming that the participant verbally expressed his/her willingness to participate in the study, and (6) signature of the interviewers. No incentive was offered for study participation. The whole survey took around 20 min to complete. The same data collection method was used in a number of published studies ,40,41,42A panel of researchers in public health, behavioral health, and vaccination behaviors was formed to design the questionnaire used in this study. The questionnaire was pilot tested among 10 older adults to assess clarity and readability. All the older adults participating in the pilot study indicated that the items of the questionnaire were easy to understand and the length of the questionnaire was acceptable. These older adults did not participate in the actual survey. The panel finalized the questionnaire based on their comments.Information on socioeconomic characteristics was collected, such as gender, age, educational level, relationship status, employment status, household income level, whether living alone, and whether they were receiving Comprehensive Social Security Assistance (CSSA). Participants also reported their current health condition and history of seasonal influenza vaccination, pneumococcal vaccination, and COVID-19 infection.Information on the vaccination status of the participants, including the number of vaccine doses, the timing and type(s) of vaccine received and any side effects after vaccination, was collected. Vaccine hesitancy was measured using the same definition as in published studies ,44. It wRegarding perceptions about COVID-19, we added one new item “How high is your chance of having close contact with people having COVID-19?” to a validated item measuring perceived susceptibility to COVID-19 ,38, and One single item was constructed to measure vaccine fatigue . The response categories for the above items were 1 = disagree, 2 = neutral, 3 = agree.Validated items were adapted to measure the frequency of exposure to the following contents on TV, radio, newspaper, and Internet: (1) people infected with COVID-19 after receiving three doses of COVID-19 vaccines, and (2) people recovered from COVID-19 without seeking medical consultation . We usedThe targeted sample size of this study was 360. We assumed 50% of the elderly population intended to receive a second COVID-19 vaccine booster dose. With the assumption of the prevalence of behavioral intention in the reference group (without a facilitating condition) to be 10–40%, this targeted sample size could be able to detect the smallest odds of 1.76 between individuals with or without a facilitating condition . The same sample size planning approach was used in published studies .p < 0.05 was considered statistically significant.We followed the statistical methods used in a number of published studies ,41,46. TAbout half of the participants were 65–69 years (49.2%) and female (60.8%). The majority of them were married or cohabited with a partner (74.6%), did not receive tertiary education (89.2%), were without a full-time or part-time job (86.2%), and had a monthly household income below HKD 20,000 (USD 2580) (73.8%). Over half had at least one chronic condition (60.3%). The most prevalent chronic condition was hypertension (46.8%), followed by diabetes mellitus (18.9%) and chronic cardiovascular diseases (10.8%). Among the participants, 25.4% reported a history of COVID-19 infection. At the survey time, 66.2% had received a seasonal influenza vaccination and 28.6% had received pneumococcal vaccination in their lifetime .Among the participants, 3.5% (n = 13) received a second COVID-19 vaccine booster dose. More participants chose Comirnaty  rather than CoronaVac  as their second booster dose. The majority reported no side effects (46.2%), and the side effects were very mild or mild (46.2%) with the second booster dose. The prevalence of hesitancy to receive the second booster dose was 52.4% .For perceived susceptibility, 3.8% and 24.0% of the participants perceived the chance of COVID-19 infection and having another wave of COVID-19 outbreak in Hong Kong was high/very high, respectively. For perceived severity, 21.1%, 10.5%, and 33.0% perceived the chance of having severe illness, financial difficulties caused by COVID-19, and transmitting COVID-19 to family members was high/very high, respectively .Regarding perceptions related to the second COVID-19 vaccine booster dose, the majority had positive attitudes toward the second COVID-19 vaccine booster dose, such as the belief that a second booster dose was highly effective in preventing severe consequences of COVID-19 (73.8%), could maintain their antibody level and strengthen the protection against COVID-19 (59.2%), and was highly effective in protecting them from the Omicron variant (47.8%). About 34.1% and 20.0% were concerned that the presence of chronic diseases would decrease the protection of the second booster dose and that the duration of protection offered by the second booster dose was shorter among people with older age, respectively. About a quarter (27.0%) reported that their family doctors would suggest them to receive the second booster dose and less than half (43.8%) reported that their family members would suggest them to receive the second booster dose. The majority (86.8%) were confident to receive the second booster dose. However, over half (54.3%) reported that they were tired of receiving repeated COVID-19 vaccination (vaccine fatigue) .Females had a higher level of hesitancy to receive the second COVID-19 vaccine booster dose than males  . After aKey findings of the study:Half of the participants (52.4%) were hesitant to receive the second COVID-19 vaccine booster dose.Perceived benefits, cues to action, and perceived self-efficacy of receiving the second booster dose were associated with lower vaccine hesitancy.Perceived barriers and vaccine fatigue (tired of receiving repeated COVID-19 vaccination) were associated with higher vaccine hesitancy.To our knowledge, this is one of the first studies to examine the hesitancy to receive the second COVID-19 vaccine booster dose and its associated factors among older adults in China. Factors at the individual level were determinants of hesitancy to receive the second booster dose. The findings provided a knowledge basis to develop tailored behavioral interventions to reduce vaccine hesitancy to receive the second booster dose among older adults.In this study, the socioeconomic and educational status of the study populations were similar to the general population aged 65 years or above reported by the Hong Kong government ,48,49. HThe findings provided some empirical insights for developing interventions to decrease vaccine hesitancy of receiving the second COVID-19 vaccine booster dose. The majority of participants perceived some benefits of receiving the second COVID-19 booster dose, notably that it was highly effective in preventing severe consequences of COVID-19 (73.8%) and it could maintain their antibody level and strengthen the protection against COVID-19 (59.2%). Those who scored higher in perceived benefit were less hesitant to receive the second booster dose. Future health promotion campaigns should strengthen such beliefs among older adults. About one-third of participants (34.1%) had concerns about the presence of chronic diseases that would decrease the protection of the second booster dose. One-fifth of the participants (20.0%) had concerns about the shorter duration of protection offered by the second booster dose among older adults. It is important to address such concerns among older adults as they were significantly associated with higher hesitancy to receive the second booster dose. Health promotions should clearly convey a message to the older adults that receiving the second booster dose could protect people with chronic diseases and there is no significant difference between the duration of protection for older adults and younger adults. Perceived cue to action and self-efficacy were both facilitators. Future programs should encourage significant others, such as family doctors and members, to give reminders to receive the second booster dose as a strong cue to action. To increase self-efficacy, creating a promotional video including a role model  demonstrating the specific procedures to take up the second booster dose and facilitating them to form an action plan are potentially useful strategies. This study had several limitations. First, selection bias existed due to non-response. The refusals might have different characteristics compared to the participants and we were not able to know how non-response would affect the results. However, our response rate was comparable to random telephone surveys on vaccination behaviors among community-dwelling older adults of previous studies ,41,42. SCommunity-dwelling older adults aged 65 years or above in Hong Kong reported a high level of vaccine hesitancy to receive the second COVID-19 vaccine booster dose. Health authorities should address vaccine fatigue and concerns about the interaction between the presence of chronic diseases and the second booster dose. Strengthening perceived benefits, involving significant others of older adults, and increasing perceived self-efficacy to receive the second booster dose might also be useful strategies in this age group.


Participants who reported reliance on information about the COVID-19 vaccination from the Ministry of Health websites were more willing to accept booster doses . The leading causes behind booster dose rejection were the beliefs that booster doses have no benefit (48.35%) and have severe side effects (25.6%). Determinants of booster dose acceptance were age (odds ratio (OR) = 1.02, 95% confidence interval (CI): 1.01–1.03, p = 0.002), information provided by the Ministry of Health , perceived susceptibility to COVID-19 infection , perceived severity of COVID-19 , and perceived risk of side effects . Booster dose acceptance in EMR is relatively high. Interventions based on HBM may provide useful directions for policymakers to enhance the population’s acceptance of booster vaccination.Coronavirus disease (COVID-19) booster doses decrease infection transmission and disease severity. This study aimed to assess the acceptance of COVID-19 vaccine booster doses in low, middle, and high-income countries of the East Mediterranean Region (EMR) and its determinants using the health belief model (HBM). In addition, we aimed to identify the causes of booster dose rejection and the main source of information about vaccination. Using the snowball and convince sampling technique, a bilingual, self-administered, anonymous questionnaire was used to collect the data from 14 EMR countries through different social media platforms. Logistic regression analysis was used to estimate the key determinants that predict vaccination acceptance among respondents. Overall, 2327 participants responded to the questionnaire. In total, 1468 received compulsory doses of vaccination. Of them, 739 (50.3%) received booster doses and 387 (26.4%) were willing to get the COVID-19 vaccine booster doses. Vaccine booster dose acceptance rates in low, middle, and high-income countries were 73.4%, 67.9%, and 83.0%, respectively ( Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome (SARS-CoV-2), is still sweeping the globe. The pattern of infection and mortality due to COVID-19 differed significantly across countries . As of 10) by 53% , whereas NPIs and vaccination reduced transmission by 35% and 38%, respectively. So, both measures should be implemented simultaneously.COVID-19 control is based on the strength of non-pharmaceutical interventions (NPIs) and the pace of infection development or decay, the speed with which the vaccine can be rolled out, vaccine targeting and uptake, and vaccine characteristics . AlthougGlobally, a total of 12,613,484,608 vaccine doses have been delivered as of September 12, 2022 , in an aRecent clinical investigations have shown that the frequencies of confirmed COVID-19 and severe illness dramatically decreased with the third and fourth doses of inactivated or mRNA vaccine . Other rThe East Mediterranean region (EMR) consists of 22 countries , Tunisia, Syrian Arab Republic, Sudan, Somalia, Qatar, Pakistan, Oman, Occupied Palestine Territory, Morocco, Libya, Lebanon, Kuwait, Jordan, Iraq, Iran, Egypt, Djibouti, Bahrain, and Afghanistan). These countries are of different income levels and health system capacities . This gaStudies about the acceptance of COVID-19 vaccine booster doses in the EMR are scarce. A study in Jordan reported that about 50% of the population have concerns about the side effects of vaccination, which might prevent them from receiving booster shots of vaccines, and 45.3% thought that receiving a third dose of the vaccine would exacerbate the side effects . Higher In this study, we aimed to explore the acceptance of COVID-19 vaccine booster doses in low, middle, and high-income countries of the EMR and its determinants by using the Health Belief Model (HBM) constructions. The Health Belief Model is one of the most popular models for analyzing individuals’ behavior towards vaccination against COVID-19 . The modA cross-sectional method was adopted to collect data from 14 EMR countries from March to June 2022. Based on the World Bank classification, the countries chosen were either low-income , middle-income , or high-income countries . An anonymous online survey was distributed by a team of researchers via social media platform and messaging platforms. A convenience and snowball sampling techniques were used to recure the participants who must meet the following eligibility criteria for participation in this study: aged 18 years or older, had received two doses of the COVID-19 vaccine (or a single dose of the Johnson & Johnson vaccine), had a mobile phone or computer, educated to self-complete the survey, and residents in the EMR during the COVID-19 pandemic.Epi-info 7 was used to estimate the minimum size of the required sample. With a 5% margin of error, 95% confidence level, 50% response rate, and a previously estimated rate of 60.0% for COVID-19 vaccine acceptance, a sample size of 642 (from the EMR) was considered sufficient. However, the sample size was doubled to compensate for stratification during the analysis of data and enhance the power of the study findings.A questionnaire of two domains was created to collect the data. The first domain collected (i) sociodemographic and health condition data  and (ii) attitude towards the booster dose .The second domain (HBM questionnaire) included 11 items that were used to assess the perceptions of COVID-19 infection and booster vaccination. The HBM consists of the following 6 domains: (i) Perceived susceptibility to COVID-19 infection: it consists of two items and refers to one’s beliefs about the chances of worsening his/her health condition. (ii) Perceived severity of COVID-19 which refers to one’s feeling about the seriousness of his/her health condition, ability to worsen, or failure to treat the illness. This item also consists of two items. Moreover, the perceived severity domain includes one’s evaluation of medical and clinical outcomes such as fatality, infirmity, and discomfort, as well as potential consequences on her/his daily social activities such as the effects of their medical condition on work productivity, family activities, and social interactions and relations. According to the HBM, perceived threats were defined as the combination of perceived susceptibility and perceived severity. Thus, the first and second domains can be applied under one domain labeled “perceived threats’’. (iii) Perceived benefit of COVID-19 booster indicates that the individual’s beliefs about the perceived benefits of the various available actions for reducing the disease threat are influenced by his/her perception of the threat, regardless of whether or not that perception ended with a behavior change. This domain consists of three items, (iv) a perceived barrier to receiving COVID-19 booster doses, which indicates the impending negative consequences and aspects of a particular health action that may considerably act as obstacles to engagement in recommended health behaviors. This domain consists of three items. As per the HBM, perceived susceptibility and perceived benefits could only be potentiated by other independent factors, particularly by clues used to prompt actions, namely “cues to action”, such as physical condition, or by environmental factors, such as media. (v) self-efficacy has been elaborated on by the HBM as an essential factor that may encourage certain behavior. Moreover, it is defined as “the conviction that one can successfully execute the behavior required to produce the outcomes” . The responses to the questionnaire’s items were aggregated as follows: high (high/very high), neutral, and low (low/very low). All domains of the HBM questionnaire had an acceptable level of validity as Cronbach’s Alpha value was ≥0.6, except the perceived barrier was 0.59 . Of the The questionnaire was administered in Arabic  and English  to eliminate the difficulties of language as previously suggested . The facAn electronic form of the questionnaire was designed using Google Forms and distributed via different social media (Facebook and Twitter) and messaging platforms (WhatsApp and emails) from March to June 2022. Before actual data collection, the research team tested the feasibility and accessibility of the online tool in a pilot study. Each collaborator was asked to submit at least two responses to determine the time required for completing the survey and the feasibility of the study. A total of 2327 individuals responded to the questionnaire. About 806 (34.6%) were excluded as they either did not receive the vaccination at all or did not complete the compulsory schedule of COVID-19 vaccination. Another 53 (2.3%) responses were omitted as the responders were not living in EMR countries or the responses were unsatisfactory. Finally, 1468 were included in the analysis; 375 (25.5%) refused to get the booster, 739 (50.3%) received booster doses, and 387 (26.4%) were willing to get the booster doses. In The Ethics Committee of the High Institute of Public Health, Alexandria University, Egypt approved the study. Information about the study’s purpose, anonymity, confidentiality, voluntary participation, and privacy statements was provided on the survey cover page to all participants who were prompted “to agree” or “not to agree” to participate in the study. Those who clicked “I agree to participate” were able to access the questionnaire. Data were protected and saved in a password-accessible computer available only to the principal investigator.p-value < 0.05 was considered statistically significant.The data were managed and analyzed using the R 4.2.1 software . Numerical variables were presented using mean ± standard deviation (SD), whereas nominal and categorical variables were expressed as a percentage (%). A Chi-Square test was used to assess the association between the nonnumerical variables, and the responses were categorized into Yes or No based on receiving COVID-19 booster doses. An independent t-test was performed to compare the difference between the means of two independent groups. Cronbach’s alpha test was deployed to assess the internal consistency of the domains and their items. A binary logistic regression analysis was conducted to estimate the significant predictors’ odds ratios, and a confidence interval of 95%  was reported. The dependent variable was the actual or virtual acceptance of COVID-19 booster vaccination, which was defined based on the following questions: “Have you received the booster dose of COVID-19 vaccine” or “Will you get the booster dose of COVID-19 vaccine” (Yes/No)”. A The mean age of the respondents was 36.53 ± 13.45, ranging from 18–88 years; females represented 62.7% (920); more than half of them were married 55.2%, (811); nearly one half 48.0% (705) had a university degree; about one-third 35.8% (526) were working in the medical field; 16.1% (237) had chronic diseases; and those who had COVID-19 infection before accounted for 51.1% (750); those who had relatives that had COVID-19 infection represented 86.4% (1268); and those with relatives who were immunocompromised and living in the vicinity of the participant made up 14.3% (210) of respondents .p < 0.001 There was a significant difference in booster dose acceptance among the included EMR countries, being the highest in low-income countries at 73.4% (141/192), and lowest in middle-income countries at 17.0% (480/707) at p = 0.001. The mean age of respondents who accepted vaccination was significantly older than those who accepted vaccination . The mean BMI of respondents who accepted booster doses tended to be higher than those who rejected (26.2 ± 5.5 vs. 25.6 ± 5.8). However, this difference was insignificant (p = 0.075). Being married was significantly associated with booster dose acceptance, as 77.7% of those who were married versus 69.6% of those who were single accepted booster dose, with p = 0.003. About 71.1% (533/750) of respondents -19 previously infected with COVID vs. 78.0 (560/718) of non-previously infected respondents accepted booster doses (p = 0.003). About 75.5% (959/1258) of those who accepted vaccination had no immunocompromised person living in the same context compared to 68.1% (143/210) of participants who had immunocompromised relatives (p = 0.028). Neither occupation, chronic diseases, nor having a relative who was infected with COVID-19 were associated with booster dose acceptance , ceptance .The leading causes behind booster dose rejection were the beliefs that the booster vaccine has no benefit 48.35% (181/375) and that it has severe side effects 25.6% (96/375). About 15.5% (58/375) refused to answer this question. p < 0.001) , the Center for Diseases Prevention and Control (CDC) website 53.6% (787/1468), followed by the Ministry of Health (MOH) website 41.3% (905/1468). However, 79.3% (718/905) of those who did follow the information provided by the MOH website accepted booster doses compared to 66.6% (375/863) of those who did not follow this source of information; this difference was statistically significant (< 0.001) .p < 0.05) except for question 13 (cues to action) as shown in All domains of the HBM  were statistically significant across vaccinated and unvaccinated groups (p = 0.002), information source as Ministry of Health and population  were significant determinants of COVID-19 booster dose acceptance. Regarding the HBM, perceived susceptibility to COVID-19 infection , perceived severity of COVID-19 , and perceived risk of side effects  were the significant predictors of COVID-19 booster dose acceptance.The present study demonstrated a high COVID-19 vaccination booster acceptance rate (74.46%) among the population in the EMR. This figure is substantially higher than a recently published study by Abuzaid et al., . They reIn the current study, vaccine acceptance was significantly higher in high-income countries compared to low- and middle-income countries. Indeed, high-income countries received more doses from manufacturers in order to vaccinate a larger proportion of their population. On the other hand, Arce et al.,  reportedIn our univariate analysis, being female, younger age, being single, having a university degree or being postgraduate, and previous COVID-19 infection were significantly associated with booster dose acceptance. However, in multiple regression, age and the information provided by the Ministry of Health were the only significant determinants of vaccine acceptance. On the other hand, Lai et al.,  reportedWe used the HBM to predict booster dose vaccine acceptance in the current study, and the questionnaire has a satisfactory level of internal consistency among the studied sample. In line of previous studies, our study findings showed that the HBM aspects served as a valuable framework for this study’s assessment of participants’ attitudes concerning a booster dose of the COVID-19 vaccination. In the univariate analysis, except for question 13, all items of all constructs of the HBM were significantly associated with booster dose acceptance. In contrast, in the multivariable analysis, perceived susceptibility, perceived severity, and perceived barriers were significant predictors of booster dose acceptance. For example, Wang et al.,  found thOur study aimed to look into the individuals who were hesitant to receive a COVID-19 vaccine booster to better understand the contributing factors. Interestingly, we found that most of them thought that booster doses had no benefit, and about one-fourth refused vaccination as they witnessed severe side effects among vaccinated individuals. A prior study by Al-Qerem et al., , similarIn the same vein, Lin et al.,  found thInfodemic have a negative impact on the COVID-19 pandemic in terms of the increased frequency of self-treatment,  non-compFinally, although the COVID-19 pandemic has been successfully controlled in many countries, SARS-CoV-2 still seriously threatens the world’s health . Indeed,There are several limitations to this study. First, due to the intrinsic disadvantages of cross-sectional online surveys, a sampling bias may exist to limit the representativeness of the results . Second,A third dose of the COVID-19 vaccination was acceptable to 74.47% of the EMR inhabitants in this regional cross-sectional study. Acceptance behaviors, increased age and the HBM construct were highly associated. However, there may be some reluctance due to public skepticism regarding the safety and efficacy of current vaccines in practical settings. Our findings can therefore assist policymakers in creating more precise and scientific roll-out plans for the third COVID-19 vaccine, which is crucial when a further outbreak is still conceivable.