Causes of Vaccine Hesitancy in Adults for the Influenza and COVID-19 Vaccines: A Systematic Literature Review

Specialized Vaccine Care for Adverse Events Following Immunization and Impact on Vaccine Hesitancy in the Military Health System

INTRODUCTION

The World Health Organization identified vaccine hesitancy as one of the top 10 threats to global health. Vaccine hesitancy is defined as a delay in acceptance or refusal of vaccination despite the availability of vaccination services. Because vaccine safety concerns are important contributors to hesitancy, people who have experienced adverse events following immunization (AEFI) may be at especially high risk for subsequent vaccine hesitancy. The Defense Health Agency Immunization Healthcare Division (DHA IHD) provides specialized vaccine care to persons who have experienced AEFI. The impact of this specialized vaccine care on subsequent vaccine hesitancy has not been fully explored.

MATERIALS AND METHODS

A cohort of patients (n= 146) was identified among those who received consultative care from DHA IHD clinicians for AEFI concerns between April 2017 and September 2022. Analyses were restricted to non-uniformed beneficiaries of the Military Health System (MHS). Uniformed beneficiaries of the MHS were excluded from this analysis since vaccination mandates preclude the use of vaccine uptake as a measure of vaccine hesitancy. Outcomes were evaluated by reviewing MHS vaccination records after initial AEFI consultation through January 2023. Vaccine acceptance was considered the inverse of hesitancy, and was defined by: (a) receipt of any subsequent vaccination, (b) receipt of seasonal influenza vaccine, (c) receipt of subsequent doses of the AEFI-associated vaccine, if clinically recommended, and (d) receipt of COVID-19 vaccine.

RESULTS

A diverse group of patients with a wide range of AEFI concerns received specialized vaccine care from DHA IHD clinicians during this period. Among the cohort, 78% of patients received any subsequent vaccination, 55.2% received seasonal influenza vaccine, 57.8% received a subsequent dose of their AEFI-associated vaccine when the vaccine was clinically recommended, and 48.9% received COVID-19 vaccine. The proportion of patients who received influenza vaccine exceeded the reported rate of influenza vaccine uptake by the general population during this time period.

CONCLUSION

Specialized vaccine care after AEFI concerns was associated with relatively high acceptance of subsequent vaccinations. The experiences of DHA IHD clinicians, in providing specialized vaccine care to AEFI patients, may serve as a model for other organizations that are working to reduce vaccine hesitancy, even beyond the MHS.

COVID-19 and influenza vaccine-hesitancy subgroups

Health communicators are faced with the challenge that people can hesitate vaccines for different reasons. Our aim was to identify and describe the qualities of distinct COVID-19 and influenza vaccine-hesitancy subgroups to facilitate the development of tailored vaccine-hesitancy communication. In two studies, we used agglomerative hierarchical cluster analysis to identify COVID-19 (N = 554) and influenza (N = 539) vaccine-hesitancy subgroups in the general population based on nine vaccine hesitancy-related variables (intent to get vaccinated, perceived vaccine safety, perceived vaccine efficacy, perceived disease threat, perceived vaccination responsibility, perceived vaccination convenience, distrust in authorities, conspiracy mentality, and reliance on anecdotal testimonies). We identified and described six distinct COVID-19 vaccine-hesitancy subgroups (the Vaccination Positive, the Ambivalent, the Fearing Skeptic, the Unconvinced, the Constrained Skeptic, and the Vaccination Opponent), and three influenza vaccine-hesitancy subgroups (the Vaccination Positive, the Complacent, and the Vaccination Opponent), with different levels of hesitancy. We discuss the implications of the results for health communicators. Our results shed light on the (dis)similarities between people who hesitate COVID-19 and influenza vaccines and suggest that there is greater variety in hesitancy concerning COVID-19 vaccinations than influenza vaccinations. These findings can be used to design and test tailored vaccination messages.

The Impact of Motivational Interviewing and MOTIVE Tool Use by Pharmacists on Vaccine Acceptance

Vaccines have played a significant role in reducing infectious disease burden. However, vaccine hesitancy remains a persistent challenge in public health, including for pharmacists who often interact with patients regarding vaccines. Thus, this study assesses the impact of motivational interviewing (MI) training and the MI-based vaccine hesitancy discussion tools (MOTIVE) on pharmacists' management of vaccine hesitancy. Pharmacists in eight Midwestern pharmacy practices who completed MI and MOTIVE training and engaged with vaccine-hesitant patients participated in this study. The pharmacist participants completed post-encounter surveys identifying the vaccine discussed, the tool utilized, and the outcome of the conversation. Descriptive results from 362 encounters indicated that the primary reasons for hesitancy were safety (39%), care coordination (31.5%), and efficacy (30.4%). Post encounter, 35.4% of patients received vaccines, 26% planned to, 25.1% considered it, and 13.5% were uninterested. The findings highlight the importance of patient-centered communication, such as MI, between patients and pharmacists to identify and address reasons for vaccine hesitancy. Pharmacists, equipped with conversation tools such as the MOTIVE tools, may effectively influence vaccine acceptance. Future research should evaluate the utility of MI and the MOTIVE tools in other settings and regions.

Inoculation hesitancy: an exploration of challenges in scaling inoculation theory

Inoculation theory research offers a promising psychological 'vaccination' against misinformation. But are people willing to take it? Expanding on the inoculation metaphor, we introduce the concept of 'inoculation hesitancy' as a framework for exploring reluctance to engage with misinformation interventions. Study 1 investigated whether individuals feel a need for misinformation inoculations. In a comparative self-evaluation, participants assessed their own experiences with misinformation and expectations of inoculation and compared them to those of the average person. Results exposed a better-than-average effect. While participants were concerned over the problem of misinformation, they estimated that they were less likely to be exposed to it and more skilful at detecting it than the average person. Their self-described likelihood of engaging with inoculation was moderate, and they believed other people would benefit more from being inoculated. In Study 2, participants evaluated their inclination to watch inoculation videos from sources varying in trustworthiness and political affiliation. Results suggest that participants are significantly less willing to accept inoculations from low-trust sources and less likely to accept inoculations from partisan sources that are antithetical to their own political beliefs. Overall, this research identifies motivational obstacles in reaching herd immunity with inoculation theory, guiding future development of inoculation interventions.

Determinants of uptake of influenza, zoster and pneumococcal vaccines in patients with cardiovascular diseases

BACKGROUND

Globally, cardiovascular disease (CVD) is the leading cause of death and illness. Vaccine-preventable infections may increase acute coronary vascular disease events and the risk of complications. Low vaccine coverage has been reported among adults at high risk of complications from vaccine-preventable infections. There is a gap in research evidence around determinants of uptake of vaccines among adults with CVD. This study examined the uptake of influenza, pneumococcal and zoster vaccines and the determinants of uptake of the vaccines among cardiac patients.

METHOD

A prospective cross-sectional study was carried out among hospitalised cardiac patients through an interviewer-administered questionnaire. Descriptive statistics were used to investigate self-reported uptake of influenza, pneumococcal and zoster vaccines. Univariate and multivariate analyses of participants' social demographic and clinical characteristics were conducted to identify factors for receiving influenza vaccine.

RESULTS

Low vaccination rates among 104 participants were found for influenza (45.2%), pneumococcal (13.5%) and zoster (5.8%) vaccines. The most common reason for not receiving influenza vaccine was concern about side effects. Lack of awareness about the pneumococcal and zoster vaccines was the main reason for the poor uptake of these vaccines. Australia-born participants were more likely to receive influenza vaccine than overseas-born participants. Working-age participants and, interestingly, people living with a current smoker were less likely to receive influenza vaccine.

CONCLUSION

Influenza, pneumococcal and zoster vaccine uptake among cardiac patients was low. Encouraging physician recommendations for vaccination for cardiac patients under 65 years of age and addressing vaccination challenges among people from culturally and linguistically diverse backgrounds and pharmacy, workplace, and hospital vaccination may help increase vaccination uptake among cardiac patients.

COVID-19 vaccine intentions and attitudes in Black American emerging adults with asthma

BACKGROUND

Emerging adults (aged 18-29) are less likely to receive the COVID-19 vaccine than any other adult age group. Black Americans are less likely than non-Hispanic white Americans to be fully vaccinated against COVID-19. This study explored factors which affect vaccine intention and attitudes in Black American emerging adults with asthma.

METHODS

Participants were recruited from an NHLBI-funded clinical trial to improve asthma control. Fifty-nine Black American emerging adults completed a Qualtrics survey that assessed asthma control, intention to vaccinate, and factors which may affect the decision to vaccinate. Twenty-five participants also completed a semi-structured interview via Zoom. Bivariate correlations and descriptive statistics, including Chi Square analyses, were run using SPSS. Interview thematic analyses were conducted via QDA Miner.

RESULTS

Of the 59 Black American emerging adults with asthma who completed surveys, 32.2% responded that they were highly unlikely to receive the COVID-19 vaccine, while 50.8% responded that they were highly likely to receive it. Increased asthma control was significantly correlated with a higher likelihood to discuss the COVID-19 vaccine with their healthcare provider (ρ = 0.339, α = 0.011). Concerns about immediate (ρ= -0.261, α = 0.050) and long-term (ρ= -0.280, α = 0.035) side effects were inversely correlated with intention to vaccinate. Only 17% of the participants who were unemployed stated that they were highly likely to receive the vaccines compared to 65% of the participants who were employed; however, interview participants who were unemployed stated not needing the vaccine because they were protecting themselves by social distancing. When deciding whether to receive the vaccine, safety, efficacy, and immediate side effects were the top three factors for 91%, 54%, and 49% of the participants, respectively. Beliefs about the vaccines' safety and efficacy, information gathering, personal factors, and societal factors emerged as important themes from the interviews.

CONCLUSION

Only half of the surveyed Black American emerging adults with asthma were highly likely to receive the COVID-19 vaccine. Safety and efficacy were important for the majority of the participants, regardless of vaccine intention. Greater asthma control, but not access to asthma-related healthcare, was correlated with intention to discuss the vaccine with their healthcare provider.

COVID-19 vaccine hesitancy among adults in India: A primary study based on health behavior theories and 5C psychological antecedents model

Despite the significant success of India's COVID-19 vaccination program, a sizeable proportion of the adult population remains unvaccinated or has received a single dose of the vaccine. Despite the recommendations of the Government of India for the two doses of the COVID-19 vaccine and the precautionary booster dose, many people were still hesitant towards the COVID-19 full vaccination. Hence, this study aimed to identify the primary behavioral and psychological factors contributing to vaccine hesitancy. Cross-sectional data was collected via a multi-stage sampling design by using a scheduled sample survey in the Gorakhpur district of Uttar Pradesh, India, between 15 July 2022 to 30 September 2022. This study has utilized three health behavior models-the Health Belief Model (HBM), the Theory of Planned Behavior (TPB), and the 5C Psychological Antecedents of vaccination, and employed bivariate and multivariable binary logistic regression model to assess the level of vaccine hesitancy and predictive health behavior of the respondents. Results indicate that among the constructs of the HBM and 5C Antecedents models, "perceived benefits", "confidence" and "collective responsibility" showed a lesser likelihood of COVID-19 vaccine hesitancy. However, in the TPB model constructs, a 'negative attitude towards the vaccine' showed a four times higher likelihood of COVID-19 vaccine hesitancy. From the future policy perspective, this study suggested that addressing the issue of 'negative attitudes towards the vaccine' and increasing the trust or confidence for the vaccine through increasing awareness about the benefits of the vaccination in India may reduce vaccine hesitancy.

Longitudinal attenuation in political polarization: Evidence from COVID-19 vaccination adherence in Brazil

BACKGROUND

While political polarization in policy opinions, preferences, and observance is well established, little is known about whether and how such divisions evolve, and possibly attenuate, over time. Using the COVID-19 pandemic in Brazil as the backdrop, we examine the longitudinal evolution of a highly relevant and polarizing policy: adherence to the COVID-19 vaccination.

METHODS

Studies 1 (N = 3346) and 2 (N = 10,214) use nationwide surveys to document initial differences and subsequent changes in vaccination adherence between conservatives ("Bolsonaristas") and non-conservatives ("non-Bolsonaristas"). Study 3 (N = 742) uses an original dataset to investigate belief changes among conservatives and their association with asymmetric changes in vaccination adherence.

RESULTS

Despite substantial differences at the early stages of rollout, the gap in vaccination adherence between conservatives and non-conservatives significantly decreased with the passage of time, driven essentially by a much faster uptake among the initially most skeptic-the conservatives. Study 3 demonstrates that the asymmetric changes in vaccination adherence were associated with meaningful belief changes among the conservatives, especially about the perceived effectiveness of the COVID-19 vaccines and the expected adherence of peers to the vaccination campaign.

CONCLUSIONS

Together, these studies show that, in a context where the superiority of the promoted policy becomes clear over time and individuals have the opportunity to revisit prior beliefs, even intense political polarization can be attenuated.

An effective COVID-19 vaccine hesitancy intervention focused on the relative risks of vaccination and infection

We designed the Relative Risk Tool (RRT) to help people assess the relative risks associated with COVID-19 vaccination and infection. In May 2022 (N = 400) and November 2022 (N = 615), U.S. residents participated in a survey that included questions about the risks of vaccination and infection. In both cohorts, we found an association between relative risk perception and vaccine hesitancy. Participants in the May cohort were randomly assigned an intervention: to see information from the RRT or the Centers for Disease Control and Prevention (CDC). After the intervention, participants answered the same questions about risk perception and vaccination intent again. The RRT was more effective than the CDC at changing risk perception and increasing vaccination intent. In November, the survey structure was the same, but the RRT was the only intervention included, and we confirmed that the RRT was effective at changing opinions in this new sample. Importantly, the RRT provided accurate information about the risks of serious adverse outcomes to vaccination and still increased vaccination intent. Our work suggests that the RRT helps people assess relative risk, which can in turn help empower them to make informed decisions and ultimately reduce vaccine hesitancy.

Predictors of seasonal influenza and COVID-19 vaccination coverage among adults in Tennessee during the COVID-19 pandemic

Background

The COVID-19 pandemic has convoluted hesitancy toward vaccines, including the seasonal influenza (flu) vaccine. Because of COVID-19, the flu season has become more complicated; therefore, it is important to understand all the factors influencing the uptake of these vaccines to inform intervention targets. This article assesses factors related to the uptake of influenza and COVID-19 vaccines among adults in Tennessee.

Methods

A cross-sectional, secondary data analysis of 1,400 adults was conducted in Tennessee. The adult sample came from two data sources: Data source 1 completed a baseline survey from January to March 2022, and data source 2 was completed from May to August 2022. Data on vaccine attitudes, facilitators and barriers, and communication needs were collected via random digit dial by Scientific Telephone Samples (STS). Two multivariable logistic regression models were used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) to predict sociodemographic and overall vaccine-related factors associated with receipt or non-receipt (referent) of COVID-19 and influenza vaccines.

Results

Approximately 78% of the adult sample had received the COVID-19 vaccination. A significant positive association for COVID-19 vaccine uptake was seen among those who were older (aged 50-65) (aOR = 1.9; 95% CI: 1.2-3.2), Black (aOR = 2.0; 95% CI:1.3-2.8), and had a college education and higher (aOR = 2.3; 95% CI: 1.5-3.6). However, there was a significant negative association for persons reporting they were extremely religious (aOR = 0.5; 95% CI:0.3-0.9). Over 56% of the adult sample had received the influenza vaccination this season. Those who had a higher annual household income ($80,000+) (aOR = 1.9; 95% CI: 1.3-2.6) and had health insurance (aOR = 2.6; 95% CI: 1.4-4.8) had a significant positive association with influenza vaccine receipt. However, those who were employed part-time or were unemployed had a significant negative association for influenza vaccine receipt (aOR = 0.7; 95% CI: 0.5-0.9). Both COVID-19 and influenza vaccine receipt had strongly significant positive trends with increasing belief in effectiveness and trust (p < 0.0001) and strongly significant negative trends with higher levels of overall vaccine hesitancy (p < 0.0001).

Conclusion

Strategies to increase COVID-19 and influenza vaccination should be age-specific, focus on increasing geographical and financial access, and offer tailored messages to address concerns about these vaccines.

Co-Administration of Influenza and COVID-19 Vaccines: Policy Review and Vaccination Coverage Trends in the European Union, UK, US, and Canada between 2019 and 2023

Recommending co-administration of influenza and COVID-19 vaccines has emerged as a strategy to enhance vaccination coverage. This study describes the policy on co-administration and uptake of influenza and COVID-19 vaccination in Europe, the United Kingdom, the United States, and Canada between 2019 and 2023. We collected co-administration policy data from governmental websites, national health organizations, and newspapers. Influenza vaccination coverage among persons ≥65 years and COVID-19 vaccination coverage rates among persons ≥60 years or the general population were collected using national databases, the ECDC database, or ourworldindata.org between 2019 and 2023. Descriptive analyses were used. We collected data from 30/32 (94%) countries on vaccination policy in seasons 2021-2022 and 2022-2023, with most countries (25/30 to 30/30) having policies recommending co-administration. For influenza vaccination coverage, we collected data from 29/32 (91%, 2019-2020), 28/32 (88%, 2020-2021), 27/32 (84%, 2021-2022), and 6/32 (19%, 2022-2023) countries. COVID-19 vaccination was collected from 32/32 (2020-2021), 31/32 (97%, 2021-2022), and 24/32 (75%, 2022-2023) countries. Influenza vaccination coverage increased from 2019-2020 to 2021-2022. COVID-19 vaccination coverage was higher among countries with higher influenza vaccination coverage. By 2022-2023, all countries included implemented a policy supporting co-administration. A positive correlation existed between higher influenza vaccination coverage and higher COVID-19 vaccination rates.

Occupational Health Providers' Perceptions of Employee Vaccine Hesitancy

OBJECTIVE

This study examined the perspectives of occupational health providers (OHPs) on the most frequently encountered clinically relevant reasons for employee vaccine hesitancy.

METHODS

We conducted an anonymous, online, cross-sectional survey of US OHPs ( N = 217). The survey asked OHPs about the major reasons that employees cite for being unwilling to receive the following three categories of vaccines: COVID-19, annual influenza, and others relevant to the workplace.

RESULTS

Concern about adverse effects was the most frequently reported reason for employee vaccine hesitancy for each vaccine category. Mistrust was reported more frequently for COVID-19 than for the influenza vaccine or other vaccines (χ 2P < 0.05). Targets of employee mistrust included government and researchers or scientists, but mistrust of healthcare providers was uncommon.

CONCLUSIONS

These results can be used to inform interventions to address vaccine hesitancy in the occupational health setting.

The impact of comorbidities and sociodemographic predictors on pneumococcal vaccination coverage in adults with coronary heart disease

Aim: Coronary heart disease (CHD) increases the risk of adverse outcomes from invasive pneumococcal disease. Methods: Using the 2020 and 2021 data from the national health interview survey, we identified adults with CHD. Chi-square analysis and logistic regression were used to examine factors that influence vaccination status. Results: There were 2675 participants aged 41 and above with CHD. Participants were predominantly white people (82.5%) and males (60.1%). The odds of receiving the pneumococcal vaccine increased with stepwise increase in comorbidities from 1 to 2 and from 2 to 3. Among individuals with ≥2 comorbidities, black people were less likely to be vaccinated compared with white people. Conclusion: Pneumococcal vaccine uptake among adults with CHD is determined by cumulative comorbidities and ethnicity.

Identifying beliefs driving COVID-19 vaccination: Lessons for effective messaging

Increasing vaccination acceptance has been essential during the COVID-19 pandemic and in preparation for future public health emergencies. This study aimed to identify messaging strategies to encourage vaccine uptake by measuring the drivers of COVID-19 vaccination among the general public. A survey to assess COVID-19 vaccination acceptance and hesitancy was advertised on Facebook in February-April 2022. The survey included items asking about COVID-19 vaccination status and participant demographics, and three scales assessing medical mistrust, perceived COVID-19 risk, and COVID-19 vaccine confidence (adapted from the Oxford COVID-19 vaccine confidence and complacency scale). The main outcome was vaccination, predicted by patient demographics and survey scale scores. Of 1,915 survey responses, 1,450 (75.7%) were included, with 1,048 (72.3%) respondents reporting they had been vaccinated. In a multivariable regression model, the COVID-19 vaccine confidence scale was the strongest predictor of vaccination, along with education level and perceived COVID-19 risk. Among the items on this scale, not all were equally important in predicting COVID-19 vaccination. The items that best predicted vaccination, at a given score on the COVID-19 vaccine confidence scale, included confidence that vaccine side effects are minimal, that the vaccine will work, that the vaccine will help the community, and that the vaccine provides freedom to move on with life. This study improved our understanding of perceptions most strongly associated with vaccine acceptance, allowing us to consider how to develop messages that may be particularly effective in encouraging vaccination among the general public for both the COVID-19 pandemic and future public health emergencies.

Factors Influencing the Healthcare Workers' Willingness to Receive the COVID-19 Booster Dose in Tuscany (Italy)

BACKGROUND

The World Health Organization has defined vaccine hesitancy as behavior influenced by several factors, including trust in the vaccine itself or its provider or the perceived need for vaccination. The aim of this study was to investigate the factors influencing the willingness to receive the COVID-19 vaccine among the employees and healthcare professionals of the Central Tuscany Local Health Authority (CT-LHA) in Italy.

METHODS

From July to October 2022, a cross-sectional study was conducted. An online questionnaire was administered to 7000 employees of the CT-LHA. The questionnaire analyzed the factors that influenced receiving the booster dose of the COVID-19 vaccine. The sample was stratified by gender, age, type of occupation (healthcare or non-healthcare workers), and seniority. Incomplete questionnaires were excluded. A chi-squared test was performed through STATA. The significance level was set at 95%.

RESULTS

Of the questionnaires administered, 1885 (26.9%) questionnaires were eligible for the study. In the previous vaccination campaign, the healthcare workers (HCWs) considered the vaccine used by CT-LHA as safe, in contrast to non-healthcare workers (N-HCWs), who considered it less secure (p < 0.05). The HCWs showed a higher propensity for vaccine safety to receive the booster dose than N-HCWs. N-HCWs appeared to be less affected by an updated booster dose than HCWs (p < 0.05).

CONCLUSIONS

The factors studied appear to influence HCWs differently from N-HCWs. Both HCWs and N-HCWs would choose an upgraded mRNA vaccine for the booster dose.

Protocol of the process evaluation of cluster randomised control trial for estimating the effectiveness and cost-effectiveness of a complex intervention to increase care home staff influenza vaccination rates compared to usual practice (FluCare)

BACKGROUND

Influenza (flu) vaccination rates in UK care home staff are extremely low. Less than 40% of staff in care homes are vaccinated for influenza (flu), presenting risks to the health of frail residents and potential staff absence from cross-infection. Staff often do not perceive a need for vaccination and are unaware they are entitled to free flu vaccination. The FluCare study, a cluster randomised control trial (RCT), uses behavioural interventions to address barriers. Videos, posters, and leaflets are intended to raise awareness of flu vaccination benefits and debunk myths. On-site staff vaccination clinics increase accessibility. Financial incentives to care homes for improved vaccination rates and regular monitoring influence the environment. This paper outlines the planned process evaluation which will describe the intervention's mechanisms of action, explain any changes in outcomes, identify local adaptations, and inform design of the implementation phase.

METHODS/DESIGN

A mixed method process evaluation to inform the interpretation of trial findings.

OBJECTIVES

• Describe the intervention as delivered in terms of dose and fidelity, including adaptations and variations across care homes. • Explore the effects of individual intervention components on primary outcomes. • Investigate the mechanisms of impact. • Describe the perceived effectiveness of relevant intervention components (including videos, leaflets, posters, and flu clinics) from participant perspectives (care home manager, care home staff, flu clinic providers). • Describe the characteristics of care homes and participants to assess reach. A purposive sample of twenty care homes (ten in the intervention arm, ten in the control arm) for inclusion in the process evaluation. Data will include (1) study records including care home site profiles, (2) responses to a mechanism of action questionnaire, and (3) semi-structured interviews with care home staff and clinic providers. Quantitative data will be descriptively reported. Interview data will be thematically analysed and then categories mapped to the Theoretical Domains Framework.

DISCUSSION

Adopting this systematic and comprehensive process evaluation approach will help ensure data is captured on all aspects of the trial, enabling a full understanding of the intervention implementation and RCT findings.

TRIAL REGISTRATION

ISRCTN ISRCTN22729870. Registered on 24 August 2022.

Determinants of Covid-19 vaccine uptake among the elderly aged 58 years and above in Kericho County, Kenya: Institution based cross sectional survey

Hesitancy to Covid-19 vaccine is a global challenge despite the compelling evidence of the value of vaccine in preventing disease and saving lives. It is suggested that context-specific strategies can enhance acceptability and decrease hesitancy to Covid-19 vaccine. Hence, the study determined uptake and determinants of Covid-19 vaccine following a sustained voluntary vaccination drive by Kenyan government. We conducted institution based cross-sectional survey of 1244 elderly persons aged 58 to 98 years in the months of January, February and March, 2022. A multinomial logistic regression analysis was used to investigate determinants of Covid 19 vaccine uptake. The predictor variables included socioeconomic and demographic characteristics, convenience and ease of access of the vaccine, collective responsibility, complacency and the three dimensions of confidence; trust in safety, trust in decision makers and delivery system. The findings are reported as the adjusted odd ratio (AOR) at 95% confidence interval (CI). Significant level was considered at p <0.05. The results from the multinomial logistic regression analysis indicated that advanced age and presence of chronic disease were associated with increased odds of doubt on Covid 19 vaccine, while long distance from vaccination centers was associated with increased odds of delay in vaccination. Overall, the findings of this study provided valuable insights into the factors influencing vaccine hesitancy among the elderly population in Kenya and will inform the development of targeted interventions to increase vaccine acceptance and uptake in this population.

Bibliometric analysis of publication trends and topics of influenza-related encephalopathy from 2000 to 2022

BACKGROUND

Influenza-related encephalopathy is a rapidly progressive encephalopathy that usually presents during the early phase of influenza infection and primarily manifests as central nervous system dysfunction. This study aimed to analyze the current research status and hotspots of influenza-related encephalopathy since 2000 through bibliometrics analysis.

METHODS

The Web of Science Core Collection (WOSCC) was used to extract global papers on influenza-related encephalopathy from 2000 to 2022. Meanwhile, the VOSviewer and CiteSpace software were used for data processing and result visualization.

RESULTS

A total of 561 published articles were included in the study. Japan was the country that published the most articles, with 205 articles, followed by the United States and China. Okayama University and Tokyo Medical University published the most articles, followed by Nagoya University, Tokyo University, and Juntendo University. Based on the analysis of keywords, four clusters with different research directions were identified: "Prevalence of H1N1 virus and the occurrence of neurological complications in different age groups," "mechanism of brain and central nervous system response after influenza virus infection," "various acute encephalopathy" and "diagnostic indicators of influenza-related encephalopathy."

CONCLUSIONS

The research progress, hotspots, and frontiers on influenza-related encephalopathy after 2000 were described through the visualization of bibliometrics. The findings will lay the groundwork for future studies and provide a reference for influenza-related encephalopathy. Research on influenza-related encephalopathy is basically at a stable stage, and the number of research results is related to outbreaks of the influenza virus.

Psychological and Personality Characteristics Associated With COVID-19 Vaccination Behavior in Korean General Population

BACKGROUND

This study characterized coronavirus disease 2019 (COVID-19) vaccination behavior in the Korean general population using cluster analysis and explored related psychological factors.

METHODS

We categorized 1,500 individuals based on their attitudes toward COVID-19 vaccination using hierarchical clustering and identified their level of vaccine acceptance. We examined the associations between vaccine acceptance and behavioral and psychological characteristics.

RESULTS

Clustering revealed three groups according to vaccine acceptance: 'totally accepting' (n = 354, 23.6%), 'somewhat accepting' (n = 523, 34.9%), and 'reluctant' (n = 623, 41.5%). Approximately 60% of all participants who belonged to the 'totally accepting' and 'somewhat accepting' groups were willing to receive a COVID-19 vaccine despite concerns about its side effects. High vaccine acceptance was associated with older age, regular influenza vaccination, and trust in formal sources of information. Participants with high vaccine acceptance had higher levels of gratitude, extraversion, agreeableness, and conscientiousness, and lower levels of depression, anxiety, and neuroticism.

CONCLUSIONS

People weighed the benefits of COVID-19 vaccination against the risk of side effects when deciding to receive the COVID-19 vaccine. Our findings also indicate that this vaccination behavior may be affected by coping mechanisms and psychological factors.

Nationwide Survey on Seasonal Influenza Vaccination among Health Care Workers during the COVID-19 Pandemic in Greece: Determinants, Barriers and Peculiarities

BACKGROUND

Seasonal influenza vaccination (SIV) of health care workers (HCWs) is critical in protecting patients' and HCWs' health. Our objective was to examine HCW SIV coverage and related determinants.

METHODS AND MATERIALS

A nationwide cross-sectional questionnaire survey was conducted among HCWs during the first half of 2021. The questionnaire (online or paper-based) included knowledge, attitude and practice questions regarding SIV, COVID-19 vaccines and vaccination.

RESULTS

Out of 6500 questionnaires administered, 2592 were completed (response rate: 39.9%). SIV coverage reached 69.4% (95% CI: 67.6-71.2%) based on self-reported vaccine uptake. Nurses and administrative staff were found to be more skeptical and have lower vaccine acceptance in comparison with physicians (aOR = 0.66 and aQR = 0.59, respectively). Other SIV hesitancy risk factors included working in secondary health care (aOR = 0.59) and working in northern Greece (aQR = 0.66). Determinants for SIV acceptance included being or living with high-risk people due to medical history (aOR = 1.84 and aOR = 1.46, respectively), positive attitudes towards routine vaccinations (aOR: 1.86), knowledge about COVID-19 vaccines (aOR = 1.53) and COVID-19 vaccine uptake (aOR = 3.45). The primary reason for SIV refusal was low risk perception (58.7%).

CONCLUSIONS

SIV coverage (2020/2021) was relatively high, but remained far from formal recommendations. Specific occupational groups were skeptical and low-risk perception was the main reason for vaccine refusal. Targeted policies should be developed and enforced.

Sustained Increase in Very Low Influenza Vaccination Coverage in Residents and Healthcare Workers of Long-Term Care Facilities in Austria after Educational Interventions

Residents of long-term care facilities (LTCFs) are particularly at risk for influenza infections. We aimed to improve influenza vaccination coverage among residents and healthcare workers (HCWs) in four LTCFs by implementing educational programs and enhanced vaccination services. We compared vaccination coverage before and after the interventions (2017/18 and 2018/19 seasons). Data on vaccination adherence were recorded during a four-year observational period (2019/20 to 2022/23 seasons). Following the interventions, vaccination coverage increased significantly from 5.8% (22/377) to 19.1% (71/371) in residents and from 1.3% (3/234) to 19.7% (46/233) in HCWs (p < 0.001). During the observational period (2019/20 to 2022/23 seasons), vaccination coverage remained high in residents but decreased in HCWs. Vaccination adherence was significantly higher in residents and HCWs in LTCF 1 compared to the other three LTCFs. Our study suggests that a bundle of educational interventions and enhanced vaccination services can be an effective method for improving influenza vaccination coverage in LTCFs in both residents and HCWs. However, vaccination rates are still well below the recommended targets and further efforts are needed to increase vaccine coverage in our LTCFs.

COVID-19 vaccine acceptance and related behavioral and psychological characteristics in individuals with mental disorders in Korea

Objective

This study aimed to investigate COVID-19 vaccine acceptance and related factors in individuals with mental disorders in Korea.

Methods

We surveyed 572 individuals with mental disorders about their attitudes toward COVID-19 vaccination using a 7-item self-rating questionnaire on vaccine acceptance and hesitancy. We categorized the respondents into groups based on their level of vaccine acceptance using hierarchical clustering. In addition, we evaluated the respondents' vaccination status and trust in sources of information regarding COVID-19 vaccines, and assessed their psychological characteristics using the Patient Health Questionnaire-9, Gratitude Questionnaire-6, and Big Five Inventory-10.

Results

Clustering revealed three groups according to vaccine acceptance: 'totally accepting' (n= 246, 43.0%), 'somewhat accepting' (n= 184, 32.2%), and 'hesitant' (n= 142, 24.8%) groups. Three quarters of all participants, who belonged to the 'totally accepting' or 'somewhat accepting' groups, were willing to receive a COVID-19 vaccine despite concerns about its side effects. Individuals in the high vaccine acceptance group were older (F= 12.52, p< 0.001), more likely to receive the influenza vaccine regularly, and more likely to trust formal information sources. Additionally, they had higher levels of gratitude (F= 21.00, p< 0.001) and agreeableness (F= 4.50, p= 0.011), and lower levels of depression (χ²= 11.81, p= 0.003) and neuroticism (F= 3.71, p= 0.025).

Conclusion

The present study demonstrated that individuals with mental disorders were generally willing to receive COVID-19 vaccination. However, they weighed its need and effectiveness against potential side effects before coming to a decision. It is important to understand the behavioral and psychological characteristics associated with vaccine acceptance, to effectively communicate its importance to individuals with mental disorders.

COVID-19 Vaccine Hesitancy in a Population-Based Study of Minnesota Residents

COVID-19 continues to be a public health concern in the United States. Although safe and effective vaccines have been developed, a significant proportion of the US population has not received a COVID-19 vaccine. This cross-sectional study aimed to describe the demographics and behaviors of Minnesota adults who have not received the primary series of the COVID-19 vaccine, or the booster shot using data from the Minnesota COVID-19 Antibody Study (MCAS) collected through a population-based sample between September and December 2021. Data were collected using a web-based survey sent to individuals that responded to a similar survey in 2020 and their adult household members. The sample was 51% female and 86% White/Non-Hispanic. A total of 9% of vaccine-eligible participants had not received the primary series and 23% of those eligible to receive a booster had not received it. Older age, higher education, better self-reported health, $75,000 to $100,000 annual household income, mask-wearing, and social distancing were associated with lower odds of hesitancy. Gender, race, and previous COVID-19 infection were not associated with hesitancy. The most frequently reported reason for not receiving a COVID-19 vaccination was safety concerns. Mask-wearing and being age 65 or older were the only strong predictors of lower odds of vaccine hesitancy for both the primary series and booster analyses.

Profiles of People Who Carried out Late Primary Vaccination against COVID-19 in the Region of Murcia

Despite the impact of the COVID-19 vaccination, vaccine hesitancy is a matter of concern. Despite a lower disease incidence, people continue to start primo-vaccination late. The aim of this study is to characterize people late primo-vaccinated and the reasons that led them to start vaccination. A quantitative, descriptive and prospective study was performed on the basis of phone surveys of people vaccinated from February to May 2022 in the Region of Murcia (Spain). The survey included socio-demographic and COVID-19 information, self-perception risk, vaccine security, Fear of COVID-19 Scale, reasons for not being vaccinated and reasons that have led them to vaccination. From a total of 1768 people receiving primo-vaccination, 798 people were contacted, and 338 people completed the survey. Among the interviewed people, 57% reported non-health-related reasons to get vaccinated, travel reasons being the primary one. The most reported health-related reason was a fear of COVID-19. There was a significant positive association between vaccination for health-related reasons and female gender (β = 0.72), cohabiting with a vulnerable person (β = 0.97), higher self-perceived risk (β = 0.13) and vaccine security dimension (β = 0.14). We identified two different profiles of people with late COVID-19 primo-vaccination, with health-related or non-health-related reasons. This work can be useful in designing specific communication strategies.

Predictors of Seasonal Influenza Vaccination Willingness among High-Risk Populations Three Years after the Onset of the COVID-19 Pandemic

High-risk populations are at increased risk of severe influenza-related illness, hospitalization, and death due to influenza. The aim of our study was to assess the willingness of high-risk populations to take the influenza vaccine for the 2022-2023 season, and to investigate the factors associated with such willingness. We conducted a cross-sectional study in Greece in September 2022 using a convenience sample. We considered demographic characteristics, COVID-19-related variables, resilience, social support, anxiety, depression, and COVID-19-related burnout as potential predictors. Among participants, 39.4% were willing to accept the seasonal influenza vaccine, 33.9% were unwilling, and 26.8% were hesitant. Multivariable analysis identified that increased age and increased family support were associated with increased influenza vaccination willingness. Moreover, participants that have received COVID-19 booster doses were more willing to accept the influenza vaccine. In contrast, adverse effects because of COVID-19 vaccination and exhaustion due to measures against COVID-19 reduced influenza vaccination willingness. We found that the intention of high-risk populations to receive the influenza vaccine was low. Our study contributes to an increased understanding of the factors that affect vaccination willingness. Public health authorities could use this information to update vaccination programs against influenza. Emphasis should be given on safety and effectiveness issues.

Megastudies: A New Approach to Reducing Vaccine Hesitation Worldwide

Vaccine hesitancy is a considerable obstacle to achieving vaccine protection worldwide. There needs to be more evidence-based research for interventions for vaccine hesitancy. Existing effectiveness evaluations are limited to one particular hypothesis, and no studies have compared the effectiveness of different interventions. A megastudy takes a large-scale, multi-intervention, uniform participant and the same evaluation criteria approach to evaluate many interventions simultaneously and find the most effective ones. Therefore, megastudies can help us find the most effective interventions for vaccine hesitancy. Additionally, considering the complex causes of vaccine hesitancy, we design interventions that involve social factors in megastudies. Lastly, quality control and justice are critical issues for megastudies in the future.

COVID-19 vaccination-related exacerbation of seizures in persons with epilepsy

Although vaccines are generally safe in persons with epilepsy (PWE), seizures can be associated with vaccination, including COVID-19. This study assessed the occurrence of COVID-19 vaccination-related seizure exacerbations in PWE. Adult PWE who had received a COVID-19 vaccine were consecutively recruited at a tertiary epilepsy clinic between June 2021 and April 2022. Patient demographics, including epilepsy history, vaccination details, and reported adverse effects were recorded. Seizure exacerbation, defined as occurring within one week of vaccination, was assessed. Five hundred and thirty PWE received the COVID-19 vaccine. 75 % received the Comirnaty (Pfizer) vaccine as their initial dose. Most patients (72 %) were taking ≥ 2 antiseizure medications (ASM) and had focal epilepsy (73 %). One-third were 12 months seizure free at their first vaccination. 13 patients (2.5 %) reported a seizure exacerbation following their first vaccination, three of whom required admission. None were seizure-free at baseline. Six of these patients (46 %) had a further exacerbation of seizures with their second vaccine. An additional four patients reported increased seizures only with the second vaccine dose. Seizure exacerbations are infrequently associated with COVID-19 vaccination, mainly in patients with ongoing seizures. The likelihood of COVID-19 infection complications in PWE outweighs the risk of vaccination-related seizure exacerbations.

Perspectives of Older Adults on COVID-19 and Influenza Vaccination in Ontario, Canada

INTRODUCTION/OBJECTIVES

Addressing vaccine hesitancy has become an increasingly important public health priority in recent years. There is a paucity of studies that have focused on vaccine hesitancy among older adults, who are known to be at greater risk of complications from infections such as COVID-19. We aim to explore the attitudes and beliefs of older adults regarding COVID-19 and influenza vaccines in Toronto, Ontario.

METHODS

Older adults enrolled in the Student Senior Isolation Prevention Partnership (SSIPP) program at the University of Toronto were contacted to participate in a phone survey and semi-structured interview. Survey data was analyzed descriptively, and attitude toward vaccination was compared between sociodemographic groups by using Fisher's exact test. Interview audio files were transcribed verbatim and analyzed inductively for themes and sub-themes.

RESULTS

All thirty-three (100%) older adults reported that they had received the first and second doses of the COVID-19 vaccine. Twenty-six (78.8%) participants reported intent to get vaccinated against influenza or had already received the influenza vaccine that year. Notably, only 2 out 7 (28.6%) individuals who did not plan to get vaccinated against influenza believed that vaccines offered by health providers are beneficial and only 3 out of 7 (42.9%) agreed that getting vaccines is a good way to protect oneself from disease. No other significant differences in attitudes among participants were found when compared by gender, ethnicity, or education level. The qualitative data analysis of interview transcripts identified 5 themes that impact vaccine decision making: safety, trust, mistrust, healthcare experience, and information dissemination and education.

CONCLUSIONS

Our data showed that older adults in the SSIPP program generally had positive views toward vaccination, especially toward the COVID-19 vaccines. However, several concerns regarding the effectiveness of the vaccines were brought up in interviews, such as the speed at which the vaccines were produced and the inconsistency in government messaging.