Determinants and Trends of COVID-19 Vaccine Hesitancy and Vaccine Uptake in a National Cohort of US Adults: A Longitudinal Study

Patterns and predictors of COVID-19 vaccination among young adults at 44 US sites: Secondary analysis of a randomized, controlled, open-label trial, March - December 2021

BACKGROUND

The introduction of vaccines during the COVID-19 pandemic provided an opportunity to slow transmission of SARS-CoV-2, but initial uptake of COVID-19 vaccination was slow. We analyzed data from a randomized clinical trial of the mRNA-1273 vaccine (NCT04811664) to describe the patterns of uptake of COVID-19 vaccines among young adults.

METHODS

The CoVPN 3006 trial randomized adults ages 18-29 from 44 sites in the United States to receive 1) immediate mRNA-1273 vaccination from the study site, or 2) standard of care, including the option to seek vaccination at any time in the future. Randomization occurred between March and November 2021, and an observational arm of adults who declined vaccination was enrolled beginning June 2021. Among participants in the standard of care (SoC) or Vaccine Declined arms, we estimated demographic, behavioral, and health history correlates of vaccination, and the four-month cumulative incidence of COVID-19 vaccination using inverse probability weighted Kaplan-Meier estimators.

RESULTS

Among 728 SoC and 470 Vaccine Declined participants, 79% and 16% received COVID-19 vaccination, respectively. SoC and Vaccine Declined participants were more likely to seek and receive vaccination if they reported COVID-19 preventive behaviors, including wearing masks, physically distancing, and avoiding large gatherings. We identified strong predictors of vaccination in the Vaccine Declined arm, including attending class in person (adjusted risk ratio [aRR]: 0.47, 95% confidence interval [CI] 0.21, 1.03), having a COVID-19 relevant medical condition (aRR: 1.95, 95% CI: 0.89, 4.26), and avoiding large gatherings (aRR: 2.24, 95% CI: 1.18, 4.25), though low vaccination rates in this arm led to imprecise estimates.

CONCLUSIONS

Individuals who initially decline vaccination can be convinced to vaccinate, particularly if they are already practicing other forms of COVID-19 prevention. Continued outreach and education from the scientific community can combat low vaccine confidence.

Public Willingness to Mask and Vaccinate in the Future: Results From a 2023 Nationally Representative Survey of US Adults

The enduring spread of COVID-19 and other respiratory viruses highlights a need for greater focus on long-term public willingness to perform protective behaviors. Although COVID-19 is no longer considered a public health emergency of international concern, it is unknown whether people in the United States plan to continue protective behaviors to protect themselves and others against infection. To inform planning and communications, we used a nationally representative survey of 1,936 US adults to examine attitudes and intentions toward future vaccination and mask-wearing. A majority believed COVID-19 vaccines were safe (73%) and effective in protecting against serious illness (72%). One-third (33%) had strong intentions to get an updated COVID-19 vaccine most years in the future. Among those with weaker intentions (n=1,287), many cited concerns about safety (71%) and efficacy (64%), lack of trust in institutions (64%), or beliefs that prior vaccination or infection protected them (62%). Approximately two-thirds (69%) of respondents believed masks were effective in protecting the wearer from getting COVID-19, and a majority appeared moderately receptive to future public mask-wearing, particularly when there was proximate risk of infection from COVID-19 (67%) or other respiratory viruses (59%). Men, non-Hispanic White adults, younger adults, rural residents, and adults with higher incomes, without college degrees, and without serious medical conditions or physical limitations were more likely to indicate resistance toward future COVID-19 vaccination and/or mask-wearing. Findings support tailored messaging to address concerns and opportunities among different populations, as well as support for communications programs and community engagement to motivate future uptake.

The status and influencing factors of COVID-19 vaccination in patients with COPD

In this study, we investigated the status and influencing factors of coronavirus disease 2019 (COVID-19) vaccination in patients with chronic obstructive pulmonary disease (COPD). A questionnaire on COVID-19 vaccination in patients with COPD was developed. The clinical characteristics, COVID-19 vaccination status, other relevant vaccinations, and vaccination status of the patients with COPD were collected anonymously. Logistic regression analysis was used to analyze the factors influencing COVID-19 vaccination in patients with COPD. There were 1898 returned questionnaires, of which 1874 were valid. The proportion of patients who completed the COVID-19 vaccination program was 78.60%. Factors influencing the COVID-19 vaccination rate were: the age of individuals who were 75-85 years old and > 85 years old, acute exacerbation 3-4 times in the previous year, comorbid cardiovascular and endocrine system diseases, failure to take regular medication for COPD, application of non-invasive ventilation machines, believing that their current health condition has deteriorated, believing that the current COVID-19 vaccine is not safe, medical staff not specifying whether they would recommend vaccination against COVID-19, medical staff not recommending the COVID-19 vaccine, and fear of adverse reactions and aggravation of COPD. Patients with COPD had a high COVID-19 vaccination rate in China, whereas patients with pneumonia, influenza, and herpes zoster had a low vaccination rate. Improving the patients' understanding of the safety and effectiveness of the vaccine and promoting effective communication between medical staff and patients would help increase the vaccination rate of patients with COPD.

Trust in governments, public health institutions, and other information sources as determinants of COVID-19 vaccine uptake behavior in Japan

OBJECTIVES

Trust in governments and public institutions as a determinant of public health outcomes has gained increased attention since the COVID-19 pandemic. Provided historically low confidence in vaccines in Japan, investigating the role of trust in information sources and actual COVID-19 vaccination uptake behavior will be invaluable for future vaccine promotion policymaking. Therefore, the objective of this study was to elucidate the determinants of COVID-19 vaccination uptake and evaluate the relationship between trust in different information sources and COVID-19 vaccination behavior in Japan.

METHODS

For this study, we leveraged a longitudinal series of web-based surveys of 19,174 individuals in Japan conducted between 2021 and 2022 which asked questions regarding a wide range of sociodemographic and psychographic characteristics related to the COVID-19 pandemic. Determinant analysis for vaccination (at least one dose of a COVID-19 vaccine) was conducted via multiple logistic regression, and odds ratios (OR) with 95% confidence intervals (CI) were estimated.

RESULTS

After adjustment for sociodemographic determinants of vaccine uptake, aggregate trust in the systems and institutions of vaccine approval (OR: 1.42, 95% CI: 1.30-1.56), and trust in information about the COVID-19 pandemic coming from government sources (OR: 1.27, 95% CI: 1.12-1.44) were found to be consistently powerful predictors of COVID-19 vaccination. Trust in media sources including traditional media (OR: 1.21, 95% CI: 1.07-1.36), and the internet (OR: 0.77, 95% CI: 0.66-0.89) had significant and opposing effects.

CONCLUSIONS

Our findings support the broader hypothesis that trust in governments and public health institutions remains a powerful determinant for COVID-19 vaccine uptake in Japan. We also found that vaccination decision-making is a multifactorial process that includes the synthesis of trust in public institutions and media, and its interaction with psychosocial determinants such as prosociality and health literacy. We hope to apply this study's findings towards future vaccine programs for contagious diseases.

Behavioral and social drivers of COVID-19 vaccination initiation in the US: a longitudinal study March─ October 2021

Many studies have examined behavioral and social drivers of COVID-19 vaccination initiation, but few have examined these drivers longitudinally. We sought to identify the drivers of COVID-19 vaccination initiation using the Behavioral and Social Drivers of Vaccination (BeSD) Framework. Participants were a nationally-representative sample of 1,563 US adults who had not received a COVID-19 vaccine by baseline. Participants took surveys online at baseline (spring 2021) and follow-up (fall 2021). The surveys assessed variables from BeSD Framework domains (i.e., thinking and feeling, social processes, and practical issues), COVID-19 vaccination initiation, and demographics at baseline and follow-up. Between baseline and follow-up, 65% of respondents reported initiating COVID-19 vaccination. Vaccination intent increased from baseline to follow-up (p < .01). Higher vaccine confidence, more positive social norms towards vaccination, and receiving vaccine recommendations at baseline predicted subsequent COVID-19 vaccine initiation (all p < .01). Among factors assessed at follow-up, social responsibility and vaccine requirements had the greatest associations with vaccine initiation (all p < .01). Baseline vaccine confidence, social norms, and vaccination recommendations were associated with subsequent vaccine initiation, all of which could be useful targets for behavioral interventions. Furthermore, interventions that highlight social responsibility to vaccinate or promote vaccination requirements could also be beneficial.

Health Care Access and COVID-19 Vaccination in the United States: A Cross-Sectional Analysis

BACKGROUND

Although federal legislation made COVID-19 vaccines free, inequities in access to medical care may affect vaccine uptake.

OBJECTIVE

To assess whether health care access was associated with uptake and timeliness of COVID-19 vaccination in the United States.

DESIGN

A cross-sectional study.

SETTING

2021 National Health Interview Survey (Q2-Q4).

SUBJECTS

In all, 21,532 adults aged≥18 were included in the study.

MEASURES

Exposures included 4 metrics of health care access: health insurance, having an established place for medical care, having a physician visit within the past year, and medical care affordability. Outcomes included receipt of 1 or more COVID-19 vaccines and receipt of a first vaccine within 6 months of vaccine availability. We examined the association between each health care access metric and outcome using logistic regression, unadjusted and adjusted for demographic, geographic, and socioeconomic covariates.

RESULTS

In unadjusted analyses, each metric of health care access was associated with the uptake of COVID-19 vaccination and (among those vaccinated) early vaccination. In adjusted analyses, having health coverage (adjusted odds ratio [AOR] 1.60; 95% CI: 1.39, 1.84), a usual place of care (AOR 1.58; 95% CI: 1.42, 1.75), and a doctor visit within the past year (AOR 1.45, 95% CI: 1.31, 1.62) remained associated with higher rates of COVID-19 vaccination. Only having a usual place of care was associated with early vaccine uptake in adjusted analyses.

LIMITATIONS

Receipt of COVID-19 vaccination was self-reported.

CONCLUSIONS

Several metrics of health care access are associated with the uptake of COVID-19 vaccines. Policies that achieve universal coverage, and facilitate long-term relationships with trusted providers, may be an important component of pandemic responses.

Exploring the Big Data Paradox for various estimands using vaccination data from the global COVID-19 Trends and Impact Survey (CTIS)

Selection bias poses a substantial challenge to valid statistical inference in nonprobability samples. This study compared estimates of the first-dose COVID-19 vaccination rates among Indian adults in 2021 from a large nonprobability sample, the COVID-19 Trends and Impact Survey (CTIS), and a small probability survey, the Center for Voting Options and Trends in Election Research (CVoter), against national benchmark data from the COVID Vaccine Intelligence Network. Notably, CTIS exhibits a larger estimation error on average (0.37) compared to CVoter (0.14). Additionally, we explored the accuracy (regarding mean squared error) of CTIS in estimating successive differences (over time) and subgroup differences (for females versus males) in mean vaccine uptakes. Compared to the overall vaccination rates, targeting these alternative estimands comparing differences or relative differences in two means increased the effective sample size. These results suggest that the Big Data Paradox can manifest in countries beyond the United States and may not apply equally to every estimand of interest.

Vaccine rhetoric on social media and COVID-19 vaccine uptake rates: A triangulation using self-reported vaccine acceptance

The primary goal of this study is to examine the association between vaccine rhetoric on Twitter and the public's uptake rates of COVID-19 vaccines in the United States, compared to the extent of an association between self-reported vaccine acceptance and the CDC's uptake rates. We downloaded vaccine-related posts on Twitter in real-time daily for 13 months, from October 2021 to September 2022, collecting over half a billion tweets. A previously validated deep-learning algorithm was then applied to (1) filter out irrelevant tweets and (2) group the remaining relevant tweets into pro-, anti-, and neutral vaccine sentiments. Our results indicate that the tweet counts (combining all three sentiments) were significantly correlated with the uptake rates of all stages of COVID-19 shots (p < 0.01). The self-reported level of vaccine acceptance was not correlated with any of the stages of COVID-19 shots (p > 0.05) but with the daily new infection counts. These results suggest that although social media posts on vaccines may not represent the public's opinions, they are aligned with the public's behaviors of accepting vaccines, which is an essential step for developing interventions to increase the uptake rates. In contrast, self-reported vaccine acceptance represents the public's opinions, but these were not correlated with the behaviors of accepting vaccines. These outcomes provide empirical support for the validity of social media analytics for gauging the public's vaccination behaviors and understanding a nuanced perspective of the public's vaccine sentiment for health emergencies.

COVID-19 vaccine acceptance in the general population and under-resourced communities from high-income countries: realist review

OBJECTIVE

To compare vaccination willingness before rollout and 1 year post-rollout uptake among the general population and under-resourced communities in high-income countries.

DESIGN

A realist review.

DATA SOURCES

Embase, PubMed, Dimensions ai and Google Scholar.

SETTING

High-income countries.

DEFINITIONS

We defined vaccination willingness as the proportion of participants willing or intending to receive vaccines prior to availability. We defined vaccine uptake as the real proportion of the population with complete vaccination as reported by each country until November 2021.

RESULTS

We included data from 62 studies and 18 high-income countries. For studies conducted among general populations, the proportion of vaccination willingness was 67% (95% CI 62% to 72%). In real-world settings, the overall proportion of vaccine uptake among those countries was 73% (95% CI 69% to 76%). 17 studies reported pre-rollout willingness for under-resourced communities. The summary proportion of vaccination willingness from studies reporting results among people from under-resourced communities was 52% (95% CI 0.46% to 0.57%). Real-world evidence about vaccine uptake after rollout among under-resourced communities was limited.

CONCLUSION

Our review emphasises the importance of realist reviews for assessing vaccine acceptance. Limited real-world evidence about vaccine uptake among under-resourced communities in high-income countries is a call to context-specific actions and reporting.

Latino Parents' Reactions to and Engagement With a Facebook Group-Based COVID-19 Vaccine Promotion Intervention: Mixed Methods Pilot Study

BACKGROUND

Misinformation in Spanish on social media platforms has contributed to COVID-19 vaccine hesitancy among Latino parents. Brigada Digital de Salud was established to disseminate credible, science-based information about COVID-19 in Spanish on social media.

OBJECTIVE

This study aims to assess participants' reactions to and engagement with Brigada Digital content that sought to increase COVID-19 vaccine uptake among US Latino parents and their children.

METHODS

We conducted a 5-week intervention in a private, moderator-led Facebook (Meta Platforms, Inc) group with Spanish-speaking Latino parents of children aged ≤18 years (N=55). The intervention participants received 3 to 4 daily Brigada Digital posts and were encouraged to discuss the covered topics through comments and polls. To assess participants' exposure, reactions, and engagement, we used participants' responses to a web-based survey administered at 2 time points (baseline and after 5 weeks) and Facebook analytics to calculate the average number of participant views, reactions, and comments. Descriptive statistics were assessed for quantitative survey items, qualitative responses were thematically analyzed, and quotes were selected to illustrate the themes.

RESULTS

Overall, 101 posts were published. Most participants reported visiting the group 1 to 3 times (22/55, 40%) or 4 to 6 (18/55, 33%) times per week and viewing 1 to 2 (23/55, 42%) or 3 to 4 (16/55, 29%) posts per day. Facebook analytics validated this exposure, with 36 views per participant on average. The participants reacted positively to the intervention. Most participants found the content informative and trustworthy (49/55, 89%), easy to understand, and presented in an interesting manner. The participants thought that the moderators were well informed (51/55, 93%) and helpful (50/55, 91%) and praised them for being empathic and responsive. The participants viewed the group environment as welcoming and group members as friendly (45/55, 82%) and supportive (19/55, 35%). The 3 most useful topics for participants were the safety and efficacy of adult COVID-19 vaccines (29/55, 53%), understanding child risk levels (29/55, 53%), and the science behind COVID-19 (24/55, 44%). The preferred formats were educational posts that could be read (38/55, 69%) and videos, including expert (28/55, 51%) and instructional (26/55, 47%) interviews. Regarding engagement, most participants self-reported reacting to posts 1 to 2 (16/55, 29%) or 3 to 4 (15/55, 27%) times per week and commenting on posts 1 to 2 (16/55, 29%) or <1 (20/55, 36%) time per week. This engagement level was validated by analytics, with 10.6 reactions and 3 comments per participant, on average, during the 5 weeks. Participants recommended more opportunities for engagement, such as interacting with the moderators in real time.

CONCLUSIONS

With adequate intervention exposure and engagement and overall positive participant reactions, the findings highlight the promise of this digital approach for COVID-19 vaccine-related health promotion.

Predictors of COVID-19 vaccine uptake: an online three-wave survey study of US adults

BACKGROUND

To effectively promote vaccine uptake, it is important to understand which people are most and least inclined to be vaccinated and why. In this study, we examined predictors of COVID-19 vaccine uptake and reasons for non-vaccination.

METHODS

We conducted an online English-language survey study in December-2020, January-2021, and March-2021. A total of 930 US respondents completed all surveys. Multiple logistic regression models were run to test whether the early vaccine eligibility, demographic factors, and psychological factors predict getting at least one dose of a COVID-19 vaccination in January-2021 and in March-2021.

RESULTS

The proportion of respondents who received ≥ 1-dose of a COVID-19 vaccine increased from 18% (January) to 67% (March). Older age predicted vaccine uptake in January (OR = 2.02[95%CI = 1.14-3.78], p < .001) and March (10.92[6.76-18.05], p < .001). In January, additional predictors were higher numeracy (1.48[1.20-1.86], p < .001), COVID-19 risk perceptions (1.35[1.03-1.78], p = .029), and believing it is important adults get the COVID-19 vaccine (1.66[1.05-2.66], p = .033). In March, additional predictors of uptake were believing it is important adults get the COVID-19 vaccine (1.63[1.15-2.34], p = .006), prior COVID-19 vaccine intentions (1.37[1.10-1.72], p = .006), and belief in science (0.84[0.72-0.99], p = .041). Concerns about side effects and the development process were the most common reasons for non-vaccination. Unvaccinated respondents with no interest in getting a COVID-19 vaccine were younger (0.27[0.09-0.77], p = .016), held negative views about COVID-19 vaccines for adults (0.15[0.08-0.26], p < .001), had lower trust in healthcare (0.59[0.36-0.95], p = .032), and preferred to watch and wait in clinically ambiguous medical situations (0.66[0.48-0.89], p = .007).

CONCLUSIONS

Evidence that attitudes and intentions towards COVID-19 vaccines were important predictors of uptake provides validation for studies using these measures and reinforces the need to develop strategies for addressing safety and development concerns which remain at the forefront of vaccine hesitancy.

Trends in primary, booster, and updated COVID-19 vaccine readiness in the United States, January 2021-April 2023: Implications for 2023-2024 updated COVID-19 vaccines

OBJECTIVE

COVID-19 vaccines have mitigated the severity of COVID-19 and its sequelae. The emergence of new SARS-CoV-2 variants and waning immunity conferred by COVID-19 vaccination have necessitated booster and updated COVID-19 vaccines. This study examined trends in vaccine readiness-a composite measure of intention and uptake-for the primary, booster, and 2022-2023 updated (bivalent) COVID-19 vaccines among U.S. adults.

METHODS

Data from the nationally-representative U.S. Department of Health and Human Services' COVID-19 Monthly Outcome Survey from January 2021 to April 2023 were analyzed (N = 140,180). We conducted pairwise comparisons (weighted t-tests) to assess for significant between-month differences in the proportion of participants in each vaccine-readiness category (vaccine ready, wait and see, and no vaccine intention) for the following outcomes: (1) primary; (2) booster; and (3) updated COVID-19 vaccine readiness.

RESULTS

From January 2021 to April 2023, significant increases in the primary vaccine ready group were accompanied by decreases in the wait and see and no vaccine intention groups (p < 0.001). From January to September 2022, the no booster intention group notably increased (p < 0.001), whereas the booster ready group decreased (p < 0.001), and the wait and see group remained stable (p = 0.116). From October 2022 to April 2023, the no updated vaccine intention group increased (p < 0.001), the wait and see group decreased (p < 0.01), and the updated vaccine ready group remained unchanged (p = 0.357).

CONCLUSIONS

Findings show decreased vaccine readiness for the booster and 2022-2023 updated (bivalent) COVID-19 vaccines relative to the primary COVID-19 vaccines. Implications for the 2023-2024 updated COVID-19 vaccines are discussed.

Predictive factors of coronavirus disease (COVID-19) vaccination series completion: a one-year longitudinal web-based observational study in Japan

Introduction

Addresing vaccine hesitancy is considered an important goal in management of the COVID-19 pandemic. We sought to understand what factors influenced people, especially those initially hesitant, to receive two or more vaccine doses within a year of the vaccine's release.

Methods

We conducted longitudinal Web-based observational studies of 3,870 individuals. The surveys were conducted at four different time points: January 2021, June 2021, September 2021, and December 2021. In the baseline survey (January 2021), we assessed vaccination intention (i.e., "strongly agree" or "agree" [acceptance], "neutral" [not sure], and "disagree" or "strongly disagree" [hesitance]), and assumptions about coronavirus disease (COVID-19), COVID-19 vaccine, COVID-19-related health preventive behavior, and COVID-19 vaccine reliability. In subsequent surveys (December 2021), we assessed vaccination completion (i.e., ≥2 vaccinations). To investigate the relationship between predictors of COVID-19 vaccination completion, a multivariable logistic regression model was applied. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were calculated while adjusting for gender, age, marital status, presence of children, household income category, and presence of diseases under treatment. In a stratified analysis, predictors were determined based on vaccination intention.

Results

Approximately 96, 87, and 72% of those who demonstrated acceptance, were not sure, or hesitated had been vaccinated after 1 year, respectively. Overall, significant factors associated with COVID-19 vaccine compliance included the influence of others close to the index participant (social norms) (AOR, 1.80; 95% CI, 1.56-2.08; p < 0.001), vaccine confidence (AOR, 1.39; 95% CI, 1.18-1.64; p < 0.001) and structural constraints (no time, inconvenient location of medical institutions, and other related factors) (AOR, 0.80; 95% CI, 0.70-0.91; p = 0.001). In the group of individuals classified as hesitant, significant factors associated with COVID-19 vaccine compliance included social norms (AOR, 2.43; 95% CI, 1.83-3.22; p < 0.001), confidence (AOR, 1.44; 95% CI, 1.10-1.88; p = 0.008), and knowledge (AOR, 0.69; 95% CI, 0.53-0.88; p = 0.003).

Discussion

We found that dissemination of accurate information about vaccines and a reduction in structural barriers to the extent possible enhanced vaccination rates. Once the need for vaccination becomes widespread, it becomes a social norm, and further improvements in these rates can then be anticipated. Our findings may help enhance vaccine uptake in the future.

Should vaccination status be a consideration during secondary triage?

The rapid development of widely available and effective vaccines has been integral to the international response to the COVID-19 pandemic. However, a significant minority of those offered vaccination have refused, often due to their adherence to 'anti-vax' beliefs. These beliefs include that vaccines are dangerous, render the recipient magnetic or contain government microchips.During the pandemic, numerous calls were made for those voluntarily refusing vaccination to be deprioritised when allocating scarce healthcare resources. While these calls were rejected, the likelihood of the same calls being made during future pandemics necessitates a thorough examination of the ethical implications entailed by such a policy.Here, I consider an intuitive argument for the use of vaccination status when allocating healthcare resources. This argument claims that, by avoiding vaccination, vaccine refusers are failing to fulfil a social obligation to protect those around them from harm by facilitating herd immunity. They are, therefore, less deserving of healthcare than their vaccinated peers.I explore three objections to this argument. While a first objection, asserting that no individual can be held responsible for a failure to develop herd immunity, fails, I find two further responses, respectively asserting the primacy of patient autonomy and highlighting the harms deprioritising vaccine refusers would cause to disadvantaged minorities, compelling. I, therefore, conclude that vaccination status should not be considered during healthcare resource allocation, as such discrimination would disproportionately harm marginalised communities.

Relationship between vaccine hesitancy and vaccination behaviors: Systematic review and meta-analysis of observational studies

BACKGROUND

Vaccination is crucial for prevention of infectious diseases, and identification of the impact of vaccine hesitancy on vaccination programs is crucial for early intervention and formulation of policies to alleviate vaccine hesitancy. The aim of this systematic review was to explore the relationship between vaccine hesitancy and negative vaccination behavior globally.

METHODS

We searched for observational studies in various databases. We conducted a meta-analysis using pooled odds ratios (OR) and 95 % confidence intervals (CI), performed meta regression and subgroup analysis to explore the role factors such as location and individual characteristics on the association between vaccine hesitancy and vaccination behavior.

RESULTS

A total of 46 articles were included in systematic analysis and 34 articles were included in the meta-analysis. The systematic analysis comprised 162,601 samples, whereas the meta-analysis included 147,554 samples. The meta-analysis showed that a higher rate of vaccine hesitancy was associated with an increased likelihood of adverse vaccination behaviors (all adverse behaviors: OR = 1.50, 95 % CI, 1.33-1.70, P < 0.001; unvaccinated: OR = 1.48, 95 % CI, 1.29-1.70, P < 0.001; vaccine delay: OR = 2.61, 95 % CI, 1.97-3.44, P < 0.001). The meta-regression results indicated that the heterogeneity observed was mainly from sample selection methods, age of vaccinees and the health status of participants. The results showed that parents of minor vaccinees or without high-risk health status had a higher association between vaccine hesitancy and vaccine uptake compared with populations exposed to higher health risks or adult vaccinees.

CONCLUSION

The findings provide evidence on the association between vaccine hesitancy and adverse vaccination behaviors. The results showed that these population-specific factors should be considered in future research, and during formulation of interventions and implementation of policies to improve vaccination uptake.

Who gets COVID-19 booster vaccination? Trust in public health institutions and promotion strategies post-pandemic in the Republic of Korea

INTRODUCTION

It is increasingly recognized that regular boosters will be necessary for the continued management of the COVID-19 pandemic. While vaccine hesitancy in the context of the initial COVID-19 vaccinations has been extensively studied, less is known about hesitancy around boosters in the post-pandemic era, where the immediate threat of COVID-19 has diminished.

METHODS

Using 5,584 survey responses from people who had received at least one COVID-19 vaccine dose based on a four-round survey between May and November 2022, we examined various factors that affect booster vaccine uptake and the willingness to take an additional shot. Ordinary least squares regressions were conducted to confirm the statistical significance of the findings.

RESULTS

Nearly 99% of vaccinated respondents reported having had two COVID-19 vaccine doses, while 69% of respondents reported having received a booster shot (three or more vaccine doses) and 48% reported being willing to get another shot. Booster uptake was strongly increased along with the degree of trust in the Korean Disease Control Agency (KDCA) and was also significantly associated with older age, gender, political propensity, and household income-level. When examining willingness to get an additional shot, the predictors were similar to booster vaccine uptake. However, the effect of trust in the KDCA became more salient.

CONCLUSION

The factors associated with booster uptake and willingness to continue to boost are similar to those associated with initial vaccine acceptance in the ROK, namely trust in the public health authority and older age. Despite high initial uptake in the ROK, convincing the public of the continued necessity of routine immunization against COVID-19 may pose challenges in the post-pandemic era.

Willingness to vaccinate among adults, and factors associated with vaccine acceptance of COVID-19 vaccines in a nationwide study in Poland between March 2021 and April 2022

Introduction

Despite the availability, safety and effectiveness of COVID-19 vaccines, Poland remains one of the six countries of the European Union with the lowest cumulative uptake of the vaccine's primary course in the general population. This study examined willingness to vaccinate and the associated factors in samples of unvaccinated and vaccinated adults between March 2021 and April 2022.

Methods

Data were collected using OBSER-CO, a nationwide, repeated cross-sectional study, conducted at four different time points (rounds). Data on willingness to vaccinate among the unvaccinated (at all rounds) and willingness to receive another dose in the vaccinated (at 2 rounds-after booster introduction), reasons for reluctance, sociodemographic, health, and behavioral factors were collected using a uniform questionnaire via computer-assisted telephone interviewing. In each round, more than 20,000 respondents were interviewed. To assess associations between factors and willingness to vaccinate, separate multivariable logistic regression models were fitted for each factor at each round and adjusted for confounders.

Results

Between rounds 1 and 4 (March 2021-April 2022), in the unvaccinated, willingness to vaccinate declined from 73 to 12%, whereas in the vaccinated, willingness to receive another dose declined from 90 to 53%. The highest magnitude of decline between subsequent rounds occurred during the Omicron wave. Overall, concerns about side effects, effectiveness, and vaccine adverse effects were common but decreased over time. Age, gender, employment, place of residence, COVID-19 diagnosis or exposure, hospitalization, and participation in social activities were among the factors associated with willingness. However, associations changed over rounds highlighting the influence of different pandemic waves and variants.

Conclusion

We observed a declining and multifactorial willingness to vaccinate in Poland, with vaccine attitudes dynamically changing across subsequent rounds. To address vaccine concerns, sustained health communication about COVID-19 vaccines is essential, especially after the emergence of new variants.

Time-to-completion of COVID-19 vaccination primary series varies by HIV viral load status among people who inject drugs in Baltimore, Maryland

People who inject drugs (PWID) may have diminished access to essential preventive services like COVID-19 vaccination given structural and substance use barriers. We aimed to assess the role of HIV on COVID-19 vaccination uptake among adult PWID participating in the ALIVE cohort study in Baltimore, Maryland who were alive as of April 2021. We abstracted COVID-19 vaccination data from electronic medical records via the regional health information exchange. We used Kaplan-Meier method to estimate time from universal vaccine eligibility (April 6, 2021) to completion of the COVID-19 vaccination primary series (1 dose J&J or 2 doses mRNA) by HIV viral load status (uninfected, PWH [HIV-RNA < 400 copies/mL], PWH [HIV-RNA ≥ 400 copies/mL]) and Cox Proportional Hazards regression to adjust for potential confounders. Our sample (N = 960) was primarily black (77%) and male (65%) with 31% reporting recent injection drug use. Among 265 (27%) people living with HIV (PWH) in our sample, 84% were virally suppressed. As of February 22, 2022, 539 (56%) completed the primary series, 131 (14%) received a single dose of mRNA vaccine and 290 (30%) remained unvaccinated. Compared to PWID without HIV, virally suppressed PWH were more likely to complete the primary series (Adjusted Hazard Ratio [aHR]:1.23,95% Confidence Interval [95 %CI]:1.07,1.50), while PWH who were not virally suppressed were less likely (aHR:0.72,95 %CI:0.45,1.16), although this was not statistically significant. We conclude that among PWID, HIV infection and viral suppression is associated with quicker vaccination uptake, likely due to HIV care engagement. Targeted improvements along the HIV care continuum may bolster vaccine uptake.

Assessing Changes in COVID-19 Vaccine Uptake and Intentions among the Brigada Digital Latino Social Media Audience: A Repeated Cross-Sectional Study

BACKGROUND

U.S. Latinos experienced disproportionate COVID-19 impacts in terms of morbidity and mortality. Vaccination against COVID-19 is an important strategy for mitigating health impacts, and yet, vaccine uptake was slower among U.S. Latino adults compared to other racial/ethnic groups. Vaccine hesitancy has been a significant barrier within Latino communities, and exposure to misinformation has been associated with negative attitudes toward vaccination. While some COVID-19 mitigation efforts have included community-based outreach, few studies have explored the impact of community-based digital messaging in Spanish to counter COVID-19 misinformation, build trust, and promote vaccination.

METHODS

To address this gap, we conducted a one-year repeated cross-sectional study to assess changes in COVID-19 vaccine uptake, intentions, and perceived norms, as well as barriers to accessing reliable information and levels of trust in COVID-19 information sources among Latino adults exposed to Brigada Digital de Salud social media content. This culturally-tailored content disseminated on Facebook, Instagram, and X platforms was amplified by community health workers and partners, and focused on COVID-19 risk and prevention, vaccine safety and efficacy, and correcting related misinformation.

RESULTS

Statistically significant increases in COVID-19 vaccination, intentions to vaccinate children, and vaccination subjective norms were observed from May 2022 (wave 1) to April 2023 (wave 2). Among perceived difficulties accessing information, respondents indicated the most difficulty in judging the reliability of COVID-19 information in the media; however, a statistically significant decrease in perceived difficulty was observed between waves. With regard to trust in COVID-19 information sources, levels of trust were highest for healthcare providers in both waves. From wave 1 to wave 2, there were statistically significant increases in trust in the FDA to ensure COVID-19 vaccine safety and trust in the federal government to ensure child COVID-19 vaccine safety.

CONCLUSIONS

Social media messaging by trusted community-based sources shows promise as a strategy for combating health misinformation and ameliorating information access gaps for language minority populations. This digital approach represents an important tool for deploying critical information to underserved populations in public health emergency and crisis contexts, and for supporting changes in attitudes, trust, and behaviors to improve health outcomes.

Trade-Offs between Vaccine Effectiveness and Vaccine Safety: Personal versus Policy Decisions

OBJECTIVE

We aimed to investigate whether individuals' trade-offs between vaccine effectiveness and vaccine safety vary if they are asked to consider the perspective of a policymaker making decisions for others compared with the decisions they would make for themselves.

METHOD

A web-enabled discrete choice experiment survey was administered between 1 April and 1 May 2022 to participants recruited from the general population of two Southeast Asian countries (Indonesia and Vietnam). In each country, 500 participants were randomly assigned to make decisions regarding coronavirus disease 2019 (COVID-19) vaccines for others as a policymaker or in a personal capacity for their own use. Vaccines were characterized by three attributes: (1) effectiveness of the vaccine in reducing infection rate; (2) effectiveness of the vaccine in reducing hospitalization among those infected; and (3) risk of death from vaccine-related serious adverse events. A mixed logit model was utilized for analyses.

RESULTS

Based on the attributes and levels used in this study, the most important vaccine attribute was the risk of death from vaccine-related adverse events, followed by effectiveness in reducing infection rate and hospitalizations. Compared with personal decisions, the mean probability of choosing a vaccine was (1) lower, and (2) more sensitive to the changes in risk of death from adverse events in policy decisions (p ≤ 0.01).

CONCLUSIONS AND RELEVANCE

Our results suggest that, in the face of an infectious disease pandemic, individuals are likely to be more risk-averse to vaccine-related deaths when making decisions for others as a policymaker than they would for themselves.

Longitudinal assessment of COVID-19 vaccine uptake: A two-wave survey of a nationally representative U.S. sample

Understanding factors that influence those who are initially COVID-19 vaccine hesitant to accept vaccination is valuable for the development of vaccine promotion strategies. Using Ipsos KnowledgePanel®, we conducted a national survey of adults aged 18 and older in the United States. We created a questionnaire to examine factors associated with COVID-19 vaccine uptake over a longitudinal period ("Wave 1" in April 2021 and "Wave 2" in February 2022), and utilized weighted data provided by Ipsos to make the data nationally representative. Overall, 1189 individuals participated in the Wave 1 survey, and 843 participants completed the Wave 2 survey (71.6% retention rate). Those who intended to be vaccinated as soon as possible ("ASAP") were overwhelmingly vaccinated by Wave 2 (96%, 95% CI: 92% to 100%). Of those who initially wished to delay vaccination until there was more experience with it ("Wait and See"), 57% (95% CI: 47% to 67%) were vaccinated at Wave 2. Within the "Wait and See" cohort, those with income <$50,000 and those who had never received the influenza vaccine were significantly less likely to be vaccinated at Wave 2. Among those who initially indicated that they would not receive a COVID-19 vaccine ("Non-Acceptors"), 28% (95% CI: 21% to 36%) were vaccinated at Wave 2. Those who believed COVID-19 was not a major problem in their community were significantly less likely to be vaccinated, while those with more favorable attitudes toward vaccines in general and public health strategies to decrease the impact of COVID-19 were significantly more likely to be vaccinated. Overall, barriers to vaccine uptake for the "Wait and See" cohort appear to be more practical, whereas barriers for the "Non-Acceptor" cohort seem to be more ideological. These findings will help target interventions to improve uptake of COVID-19 boosters and future novel vaccines.

COVID-19 vaccination willingness and uptake among low-income Black/African American, Latino, and White adults living in the U.S

The purpose of this study was to assess differences in COVID-19 vaccine willingness and uptake between low-income and non-low-income adults and across race-ethnicity. We utilized data from the COVID-19's Unequal Racial Burden online survey, which included baseline (12/17/2020-2/11/2021) and 6-month follow-up (8/13/2021-9/9/2021) surveys. The sample included 1,500 Black/African American, Latino, and White low-income adults living in the U.S. (N = 500 each). A non-low-income cohort was created for comparison (n = 1,188). Multinomial logistic regression was used to assess differences in vaccine willingness and uptake between low-income and non-low-income adults, as well as across race-ethnicity (low-income adults only). Only low-income White adults were less likely to be vaccinated compared to their non-low-income counterparts (extremely willing vs. not at all: OR = 0.58, 95% CI = 0.39-0.86); low-income Black/African American and Latino adults were just as willing or more willing to vaccinate. At follow-up, only 30.2% of low-income adults who reported being unwilling at baseline were vaccinated at follow-up. White low-income adults (63.6%) appeared less likely to be vaccinated, compared to non-low-income White adults (80.9%), low-income Black/African American (70.7%), and low-income Latino adults (72.4%). Distrust in the government (46.6), drug companies (44.5%), and vaccine contents (52.1%) were common among those unwilling to vaccinate. This prospective study among a diverse sample of low-income adults found that low-income White adults were less willing and less likely to vaccinate than their non-low-income counterparts, but this difference was not observed for Black/African American or Latino adults. Distrust and misinformation were prevalent among those who remained unvaccinated at follow-up.

COVID-19 vaccination willingness and uptake among rural Black/African American, Latino, and White adults

PURPOSE

The purpose of this study was to assess differences in COVID-19 vaccine willingness and uptake between rural and nonrural adults, and within rural racial-ethnic groups.

METHODS

We utilized data from the COVID-19's Unequal Racial Burden online survey, which included 1,500 Black/African American, Latino, and White rural adults (n = 500 each). Baseline (12/2020-2/2021) and 6-month follow-up (8/2021-9/2021) surveys were administered. A cohort of nonrural Black/African American, Latino, and White adults (n = 2,277) was created to compare differences between rural and nonrural communities. Multinomial logistic regression was used to assess associations between rurality, race-ethnicity, and vaccine willingness and uptake.

FINDINGS

At baseline, only 24.9% of rural adults were extremely willing to be vaccinated and 28.4% were not at all willing. Rural White adults were least willing to be vaccinated, compared to nonrural White adults (extremely willing: aOR = 0.44, 95% CI = 0.30-0.64). At follow-up, 69.3% of rural adults were vaccinated; however, only 25.3% of rural adults who reported being unwilling to vaccinate were vaccinated at follow-up, compared to 95.6% of adults who were extremely willing to be vaccinated and 76.3% who were unsure. Among those unwilling to vaccinate at follow-up, almost half reported distrust in the government (52.3%) and drug companies (46.2%); 80% reported that nothing would change their minds regarding vaccination.

CONCLUSIONS

By August 2021, almost 70% of rural adults were vaccinated. However, distrust and misinformation were prevalent among those unwilling to vaccinate at follow-up. To continue to effectively combat COVID-19 in rural communities, we need to address misinformation to increase COVID-19 vaccination rates.

Intention to Vaccinate against COVID-19 in Adolescents: A Systematic Review

BACKGROUND

Multiple COVID-19 vaccines have been approved for use in adolescents; these vaccines play a critical role in limiting the transmission and impact of COVID-19. This systematic review aims to summarize the willingness of adolescents aged 10 to 19 years to receive the COVID-19 vaccination and the factors influencing their decision.

METHODS

A search of literature published between January 2018 and August 2022 was performed in Medline©, EMBASE©. and CINAHL© electronic databases. Studies published in English that assessed adolescents' intentions to receive the COVID-19 vaccine were included. Qualitative studies and those unrelated to the COVID-19 vaccine were excluded. The study was conducted based on the PRISMA guidelines.

RESULTS

Of the 1074 articles retrieved, 13 were included in the final review. Most studies were conducted in the US (n = 3) and China (n = 3). The pooled prevalence of COVID-19 vaccine acceptance among adolescents was 63% (95% CI: 52-73%). Factors influencing intent to vaccinate were divided into five categories: "Socio-demographic determinants"; "Communication about COVID-19 pandemic and vaccination"; "COVID-19 vaccine and related issues"; "COVID-19 infection and related issues" and "Other determinants". The enablers were sociodemographic factors including older age, higher education level, good health perception, and parental norms in terms of parental vaccination acceptance; perceived vaccine effectiveness and safety; a desire to protect themselves and others; recent vaccination; and anxiety. The barriers were concerns over vaccine effectiveness, safety, and long-term side effects; low perceived necessity and risk of infection; and needle phobia.

CONCLUSIONS

This review highlighted that adolescents' intent to vaccinate is driven by a desire to protect themselves and others. However, concerns over vaccine effectiveness, safety, and long-term side effects hinder COVID-19 vaccine uptake. To improve vaccination acceptance, policymakers should address adolescents' concerns via more targeted public health messaging, while schools should leverage peer norms to positively influence vaccination intent.

Factors associated with COVID-19 vaccine uptake in a US/Mexico border community: demographics, previous influenza vaccination, and trusted sources of health information

Background

COVID-19 vaccine uptake has been uneven, particularly across racial/ethnic and age groups. This study seeks to understand factors associated with COVID-19 vaccine uptake in a large cross-sectional sample of predominantly Latinos/Latinas individuals living near the US/Mexico border.

Methods

Data are extracted from a 176-item survey conducted as part of a parent study focused on the co-creation of a COVID-19 testing program for underserved communities developed through a partnership between an academic institution and a Federally Qualified Health Center. The following participant variables were examined: health history, COVID-19 symptoms, COVID-19 testing and vaccine experiences, and perceptions of sources of health information. Participant characteristics were compared using chi-square tests. Multivariate logistic regressions were used for the final statistical model.

Results

From 1 May 2021 to 30 April 2022, 4,964 adults, 66% of whom were identified as women, completed the survey. Approximately 80% of participants reported having received at least one COVID-19 vaccine. Female sex, older age, Hispanic/Latino(a) ethnicity, previous influenza vaccination, advanced education, and perceived elevated risk of COVID-19 were significantly (p < 0.05) associated with having received a COVID-19 vaccine. Regarding sources of health information, individuals who indicated they trust their doctor, healthcare provider, or the US government "a great deal" were more likely to have received a COVID-19 vaccine compared to individuals who indicated that they trusted these sources "not at all." In contrast, those who reported having "a great deal" of trust in their faith leader or their social media contacts were significantly less likely to have received a COVID-19 vaccine than those who reported that they trusted these sources "not at all."

Conclusion

Sex, education, past influenza vaccination, perceived risk of COVID-19 infection, and trust in specific sources of information were correlated with the uptake of COVID-19 vaccination. Additional research is needed to better understand why this confluence of factors, particularly the unique findings about trusted sources of information, are associated with vaccine uptake. Understanding these associations, specifically within underserved, Latino/Hispanic communities, is an important first step to inform efforts aimed at increasing and sustaining COVID-19 vaccine uptake and adoption of other public health interventions.

Between nudges and mandates: The drivers of COVID-19 vaccination intentions and subsequent uptake in Russia

Despite high levels of morbidity and mortality, as well as the widespread availability of domestic vaccines, Russia demonstrated significantly low rates of vaccination throughout the COVID-19 pandemic. This research explores vaccination intentions before the start of the immunisation campaign and the consequent uptake in Russia after the introduction of mandatory vaccination policy in certain industries and proof-of-immunisation for social activities. Using a nationally representative panel dataset, we analyse factors behind individual vaccination decisions using binary and multinomial logistic regressions. Special attention is given to the effect of employment in industries with vaccine mandates and personal factors which determine individual "nudgeability" to vaccination (e.g., personality traits, beliefs, vaccine alertness, self-perceived vaccine availability etc.). Our results show that 49 per cent of the population received at least one shot of COVID-19 vaccine by autumn 2021 after the introduction of mandatory vaccination. Vaccination intentions before the rollout of the nationwide immunisation campaign are correlated with the consequent attitudes and uptake, although the prediction is not perfect. 40 percent of vaccine refusers eventually got vaccinated, while 16 percent of vaccine supporters turned into refusers, revealing the lack of promotion of vaccine safety and effectiveness. To a large extent, vaccination refusal and hesitance are explained by vaccine alertness. Vaccine mandates significantly increased the uptake in several affected industries, especially education. These results offer important insights for designing information policy, relevant for future vaccination campaigns.

Decrease in Overall Vaccine Hesitancy in College Students during the COVID-19 Pandemic

The COVID-19 pandemic changed our world as we know it and continues to be a global problem three years since the pandemic began. Several vaccines were produced, but there was a considerable amount of societal turmoil surrounding them that has affected the way people view not only COVID-19 vaccines but all vaccines. We used a survey to compare how attitudes towards vaccination have changed in college students during the pandemic. An initial survey was administered in 2021, then a follow-up in 2022. Out of 316 respondents who answered the first survey, 192 completed the follow-up. The survey was designed to measure trends in changes to vaccine attitudes since the COVID-19 pandemic began. By comparing the first survey in 2021 and the follow-up, we found that roughly 55% of respondents' vaccine attitudes did not change, roughly 44% of respondents' attitudes towards vaccines became more positive, and only about 1% of the respondents' vaccine attitudes became more negative. Improved view of vaccines was associated with political views and increased trust in medicine and the healthcare system. Worsened opinions of vaccines were associated with a belief that the COVID-19 vaccine affected fertility.

Factors Associated With COVID-19 Non-Vaccination in Switzerland: A Nationwide Study

Objectives: We compared socio-demographic characteristics, health-related variables, vaccination-related beliefs and attitudes, vaccination acceptance, and personality traits of individuals who vaccinated against COVID-19 and who did not vaccinate by December 2021. Methods: This cross-sectional study used data of 10,642 adult participants from the Corona Immunitas eCohort, an age-stratified random sample of the population of several cantons in Switzerland. We used multivariable logistic regression models to explore associations of vaccination status with socio-demographic, health, and behavioral factors. Results: Non-vaccinated individuals represented 12.4% of the sample. Compared to vaccinated individuals, non-vaccinated individuals were more likely to be younger, healthier, employed, have lower income, not worried about their health, have previously tested positive for SARS-CoV-2 infection, express lower vaccination acceptance, and/or report higher conscientiousness. Among non-vaccinated individuals, 19.9% and 21.3% had low confidence in the safety and effectiveness of SARS-CoV-2 vaccine, respectively. However, 29.1% and 26.7% of individuals with concerns about vaccine effectiveness and side effects at baseline, respectively vaccinated during the study period. Conclusion: In addition to known socio-demographic and health-related factors, non-vaccination was associated with concerns regarding vaccine safety and effectiveness.

Factors associated with COVID-19 vaccination during June-October 2021: A multi-site prospective study

INTRODUCTION

Vaccine hesitancy presents a challenge to COVID-19 control efforts. To identify beliefs associated with delayed vaccine uptake, we developed and implemented a vaccine hesitancy survey for the COVID-19 Community Research Partnership.

METHODS

In June 2021, we assessed attitudes and beliefs associated with COVID-19 vaccination using an online survey. Self-reported vaccination data were requested daily through October 2021. We compared responses between vaccinated and unvaccinated respondents using absolute standardized mean differences (ASMD). We assessed validity and reliability using exploratory factor analysis and identified latent factors associated with a subset of survey items. Cox proportional hazards models and mediation analyses assessed predictors of subsequent vaccination among those initially unvaccinated.

RESULTS

In June 2021, 29,522 vaccinated and 1,272 unvaccinated participants completed surveys. Among those unvaccinated in June 2021, 559 (43.9 %) became vaccinated by October 31, 2021. In June, unvaccinated participants were less likely to feel "very concerned" about getting COVID-19 than vaccinated participants (10.6 % vs. 43.3 %, ASMD 0.792). Among those initially unvaccinated, greater intent to become vaccinated was associated with getting vaccinated and shorter time to vaccination. However, even among participants who reported no intention to become vaccinated, 28.5 % reported vaccination before study end. Two latent factors predicted subsequent vaccination-being 'more receptive' was derived from motivation to protect one's own or others' health and resume usual activities; being 'less receptive' was derived from concerns about COVID-19 vaccines. In a Cox model, both factors were partially mediated by vaccination intention.

CONCLUSION

This study characterizes vaccine hesitant individuals and identifies predictors of eventual COVID-19 vaccination through October 31, 2021. Even individuals with no intention to be vaccinated can shift to vaccine uptake. Our data suggest factors of perceived severity of COVID-19 disease, vaccine safety, and trust in the vaccine development process are predictive of vaccination and may be important opportunities for ongoing interventions.

Social and ideological determinants of COVID-19 vaccination status in Spain

OBJECTIVES

This study analysed the association between social and ideological determinants with COVID-19 vaccine accessibility and hesitancy in the Spanish adult population.

STUDY DESIGN

This was a repeated cross-sectional study.

METHODS

The data analysed are based on monthly surveys conducted by the Centre for Sociological Research between May 2021 and February 2022. Individuals were classified according to their COVID-19 vaccination status into (1) vaccinated (reference group); (2) willing to vaccinate but not vaccinated, proxy of lack of vaccine accessibility; and (3) hesitant, proxy of vaccine hesitancy. Independent variables included social (educational attainment, gender) and ideological determinants (voting in the last elections, importance attached to the health vs the economic impact of the pandemic, and political self-placement). We estimated odds ratio (OR) and 95% confidence interval (CI) conducting one age-adjusted multinomial logistic regression model for each determinant and then stratified them by gender.

RESULTS

Both social and ideological determinants had a weak association with the lack of vaccine accessibility. Individuals with medium educational attainment had higher odds of vaccine hesitancy (OR = 1.44, CI 1.08-1.93) compared with those with high educational attainment. People self-identified as conservative (OR = 2.90; CI 2.02-4.15) and those who prioritised the economic impact (OR = 3.80; CI 2.62-5.49) and voted for parties opposed to the Government (OR = 2.00; CI 1.54-2.60) showed higher vaccine hesitancy. The stratified analysis showed a similar pattern for both men and women.

CONCLUSIONS

Considering the determinants of vaccine uptake and hesitancy could help to design strategies that increase immunisation at the population level and minimise health inequities.

HIV Care Engagement Is Not Associated with COVID-19 Vaccination Hesitancy during the Initial Peak of the COVID-19 Pandemic among Black Cisgender Sexual Minority Men and Transgender Women in the N2 COVID Study

Background: Although there is limited literature on medication adherence (including HIV care engagement) and COVID-19 vaccine hesitancy in general populations (i.e., non-sexual or gender minority populations), even less is known about whether HIV care engagement correlates with COVID-19 vaccine hesitancy among sexual and gender minorities, especially those from intersectional backgrounds. The objective of the current study was to examine if an association exists between HIV status neutral care (i.e., current pre-exposure prophylaxis [PrEP] or antiretroviral therapy [ART] use) and COVID-19 vaccination hesitancy among Black cisgender sexual minority men and transgender women at the initial peak of the pandemic. Methods: We conducted the N2 COVID Study in Chicago from 20 April 2020 to 31 July 2020 (analytic n = 222), including Black cisgender sexual minority men and transgender women who were vulnerable to HIV as well as those who were living with HIV. The survey included questions regarding HIV care engagement, COVID-19 vaccination hesitancy and COVID-19 related socio-economic hardships. Multivariable associations estimated adjusted risk ratios (ARRs) using modified Poisson regressions for COVID vaccine hesitancy adjusting for baseline socio-demographic characteristics and survey assessment time period. Results: Approximately 45% of participants reported COVID-19 vaccine hesitancy. PrEP and ART use were not associated with COVID-19 vaccine hesitancy when examined separately or combined (p > 0.05). There were no significant multiplicative effects of COVID-19 related socio-economic hardships and HIV care engagement on COVID-19 vaccine hesitancy. Conclusions: Findings suggest no association between HIV care engagement and COVID-19 vaccine hesitancy among Black cisgender sexual minority men and transgender women at the initial peak of the pandemic. It is therefore essential that COVID-19 vaccine promotion interventions focus on all Black sexual and gender minorities regardless of HIV care engagement and COVID-19 vaccine uptake is likely related to factors other than engagement in HIV status neutral care.

Uptake of COVID-19 vaccination in people with blood cancer: Population-level cohort study of 12 million patients in England

BACKGROUND

People with blood cancers have increased risk of severe outcomes from COVID-19 and were prioritised for vaccination.

METHODS

Individuals in the QResearch database aged 12 years and above on 1st December 2020 were included in the analysis. Kaplan-Meier analysis described time to COVID-19 vaccine uptake in people with blood cancer and other high-risk disorders. Cox regression was used to identify factors associated with vaccine uptake in people with blood cancer.

RESULTS

The analysis included 12,274,948 individuals, of whom 97,707 had a blood cancer diagnosis. 92% of people with blood cancer received at least one dose of vaccine, compared to 80% of the general population, but there was lower uptake of each subsequent vaccine dose (31% for fourth dose). Vaccine uptake decreased with social deprivation (HR 0.72, 95% CI 0.70, 0.74 for most deprived versus most affluent quintile for first vaccine). Compared with White groups, uptake of all vaccine doses was significantly lower in people of Pakistani and Black ethnicity, and more people in these groups remain unvaccinated.

CONCLUSIONS

COVID-19 vaccine uptake declines following second dose and there are ethnic and social disparities in uptake in blood cancer populations. Enhanced communication of benefits of vaccination to these groups is needed.

Psychosocial factors affecting COVID-19 vaccine uptake in the UK: A prospective cohort study (CoVAccS - Wave 3)

Background

We investigated factors associated with COVID-19 vaccine uptake, future vaccination intentions, and changes in beliefs and attitudes over time.

Methods

Prospective cohort study. 1500 participants completed an online survey in January 2021 (T1, start of vaccine rollout in the UK), of whom 1148 (response rate 76.5 %) completed another survey in October 2021 (T2, all UK adults offered two vaccine doses). Binary logistic regression analysis was used to investigate factors associated with subsequent vaccine uptake. Content analysis was used to investigate the main reasons behind future vaccine intentions (T2). Changes in beliefs and attitudes were investigated using analysis of variance.

Findings

At T2, 90.0 % (95 % CI 88.2-91.7 %) of participants had received two doses of a COVID-19 vaccine, 2.2 % (95 % CI 1.3-3.0 %) had received one dose, and 7.4 % (95 % CI 5.9-8.9 %) had not been vaccinated. Uptake was associated with higher intention to be vaccinated at T1, greater perceived vaccination social norms, necessity of vaccination, and perceived safety of the vaccine. People who had initiated vaccination reported being likely to complete it, while those who had not yet received a vaccine reported being unlikely to be vaccinated in the future. At T2, participants perceived greater susceptibility to, but lower severity of, COVID-19 (p < 0.001) than at T1. Perceived safety and adequacy of vaccine information were higher (p < 0.001).

Interpretation

Targeting modifiable beliefs about the safety and effectiveness of vaccination may increase uptake.

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.

Recalled Exposure to COVID-19 Public Education Campaign Advertisements Predicts COVID-19 Vaccine Confidence

This study examined the relationship between recalled exposure to the We Can Do This COVID-19 Public Education Campaign (the Campaign) and COVID-19 vaccine confidence (the likelihood of vaccination or vaccine uptake) in the general population, including vaccine-hesitant adults (the "Movable Middle"). Analyses used three waves of a triannual, nationally representative panel survey of adults in the U.S. fielded from January to November 2021 (n = 3,446). Proportional odds regression results demonstrated a positive, statistically significant relationship between past 4-month Campaign recall and vaccine confidence, controlling for lagged reports of Campaign recall and vaccine confidence; concurrent and lagged fictional campaign recall; survey wave; and sociodemographics. Results indicated that as one moves from no Campaign recall to infrequent recall, there is a 29% increase in the odds of being in a higher vaccine confidence category. Findings offer evidence of the impact of a COVID-19 public education campaign on increasing vaccine confidence.

Effectiveness of first and second COVID-19 mRNA vaccine monovalent booster doses during a period of circulation of Omicron variant sublineages: December 2021-July 2022

Background

US recommendations for COVID-19 vaccine boosters have expanded in terms of age groups covered and numbers of doses recommended, whereas evolution of Omicron sublineages raises questions about ongoing vaccine effectiveness.

Methods

We estimated effectiveness of monovalent COVID-19 mRNA booster vaccination versus two-dose primary series during a period of Omicron variant virus circulation in a community cohort with active illness surveillance. Hazard ratios comparing SARS-CoV-2 infection between booster versus primary series vaccinated individuals were estimated using Cox proportional hazards models with time-varying booster status. Models were adjusted for age and prior SARS-CoV-2 infection. The effectiveness of a second booster among adults ≥50 years of age was similarly estimated.

Results

The analysis included 883 participants ranging in age, from 5 to >90 years. Relative effectiveness was 51% (95% CI: 34%, 64%) favoring the booster compared with primary series vaccination and did not vary by prior infection status. Relative effectiveness was 74% (95% CI: 57%, 84%) at 15 to 90 days after booster receipt, but declined to 42% (95% CI: 16%, 61%) after 91 to 180 days, and to 36% (95% CI: 3%, 58%) after 180 days. The relative effectiveness of a second booster compared to a single booster was 24% (95% CI: -40% to 61%).

Conclusions

An mRNA vaccine booster dose added significant protection against SARS-CoV-2 infection, but protection decreased over time. A second booster did not add significant protection for adults ≥50 years of age. Uptake of recommended bivalent boosters should be encouraged to increase protection against Omicron BA.4/BA.5 sublineages.

Exploring COVID-19 Vaccine Attitudes among Racially and Ethnically Minoritized Communities: Community Partners' and Residents' Perspectives

COVID-19 has disproportionately affected Black, Indigenous, and People of Color (BIPOC) communities, yet rates of COVID-19 vaccination remain low among these groups. A qualitative study was undertaken to better understand the factors contributing to low vaccine acceptance among these communities. Seventeen focus groups were conducted in English and Spanish from 8/21 to 9/22, with representatives from five critical community sectors: (1) public health departments (n = 1); (2) Federally Qualified Health Centers (n = 2); (3) community-based organizations (n = 1); (4) faith-based organizations (n = 2); and (5) BIPOC residents in six high-risk, underserved communities in metropolitan Houston (n = 11), for a total of 79 participants, comprising 22 community partners and 57 community residents. A social-ecological model and anti-racism framework were adopted to guide data analysis using thematic analysis and constant comparison, which yielded five key themes: (1) legacy of structural racism: distrust and threat; (2) media misinformation: mass and social; (3) listening and adapting to community needs; (4) evolving attitudes towards vaccination; and (5) understanding alternative health belief systems. Although structural racism was a key driver of vaccine uptake, a notable finding indicated community residents' vaccine attitudes can be changed once they are confident of the protective benefits of vaccination. Study recommendations include adopting an explicitly anti-racist lens to: (1) listen to community members' needs and concerns, acknowledge their justified institutional distrust concerning vaccines, and learn community members' healthcare priorities to inform initiatives built on local data; (2) address misinformation via culturally informed, consistent messaging tailored to communal concerns and delivered by trusted local leaders through multimodal community forums; (3) take vaccines to where people live through pop-up clinics, churches, and community centers for distribution via trusted community members, with educational campaigns tailored to the needs of distinct communities; (4) establish vaccine equity task forces to continue developing sustainable policies, structures, programs and practices to address the structural issues driving vaccine and health inequities within BIPOC communities; and (5) continue investing in an effective infrastructure for healthcare education and delivery, essential for competently responding to the ongoing healthcare and other emergency crises that impact BIPOC communities to achieve racial justice and health equity in the US. Findings underscore the crucial need to provide culturally tailored health education and vaccination initiatives, focused on cultural humility, bidirectionality, and mutual respect to support vaccine re-evaluation.

Community Health, Health Care Access, And COVID-19 Booster Uptake In Massachusetts

Booster vaccination offers vital protection against COVID-19, particularly for communities in which many people have chronic conditions. Although vaccination has been widely and freely available, people who have experienced barriers to care might be deterred from being vaccinated. We examined the relationship between COVID-19 booster uptake and small area-level demographics, chronic disease prevalence, and measures of health care access in 462 Massachusetts communities during the period September 2021-April 2022. Unadjusted analyses found that booster uptake was higher in older and wealthier areas, lower in areas with more Hispanic and Black residents, and lower in areas with a high prevalence of chronic conditions. In both unadjusted and adjusted analyses, uptake was lower in communities with more uninsured residents and those in which fewer residents received routine medical check-ups. Adjusted analyses found that areas with more vaccine providers and primary care physicians had higher booster uptake, but this association was not significant in unadjusted analyses. Results suggest a need for innovative outreach efforts, as well as structural changes such as expansion of health care coverage and universal access to care to mitigate the inequitable burden of COVID-19.

Factors related to COVID-19 vaccine hesitancy in Denmark: A national study in the autumn of 2021

AIMS

The novelty of the COVID-19 pandemic and fast-developed vaccines may increase concerns about the safety and effectiveness of the COVID-19 vaccine and thereby influence vaccine hesitancy. The aims of this study were to examine (a) the main reasons for COVID-19 vaccine hesitancy and (b) factors associated with COVID-19 vaccine hesitancy.

METHODS

A nationwide survey was conducted in the autumn of 2021 when most Danes had received at least one dose of a COVID-19 vaccine. The sample (N=13,570) was based on a random selection of individuals (⩾15 years), and data were collected via self-administered mailed questionnaires (digital and physical). The participants were asked whether they had been vaccinated against COVID-19, and if they had not, they were asked about their reasons for vaccine hesitancy. Logistic regression models were used to determine factors associated with vaccine hesitancy.

RESULTS

In all, 5,384 (39.7%) individuals completed the questionnaire. The main reasons for vaccine hesitancy were worries about adverse effects (57.6%) and the belief that natural immunity is better than vaccination (43.8%). Factors associated with vaccine hesitancy included female sex, younger age, being divorced, a country of origin other than Denmark, lower educational level, being unemployed, previously infected with COVID-19 and being worried to a greater extent about oneself and others getting infected. Mental health indicators were not associated with vaccine hesitancy.

CONCLUSIONS

COVID-19 vaccine hesitancy is likely to pose a challenge for population immunity. To reduce vaccine hesitancy and increase vaccination uptake, future vaccination programmes should focus on specific socio-demographic subgroups identified in this study.

When Adolescents Disagree with Their Vaccine-Hesitant Parents about COVID-19 Vaccination

AbstractAs we journey into the fourth year of the COVID-19 pandemic, a majority of Americans express relief at a "return to normal," experience pandemic fatigue, or embrace the idea of living with COVID-19 in much the same way we live with the seasonal flu. But transition to a new phase of life with SARS-CoV-2 does not diminish the importance of vaccination. The US Centers for Disease Control and the Food and Drug Administration recently recommended another round of booster dose for persons age 5 and up, or an initial series for those not previously vaccinated, with an updated bivalent formula that protects against both the original virus strain and Omicron subvariants that are now the dominant source of infection. By most accounts most of the population has been or will become infected with SARS-CoV-2. Suboptimal uptake of the COVID-19 vaccines among the approximately 25 million adolescents in the United States is a significant obstacle to population coverage, public health, and the health and well-being of adolescents. A major cause of low adolescent uptake is parental vaccine hesitancy. This article discusses parental vaccine hesitancy and argues that permitting independent adolescent consent to COVID-19 vaccination should be an ethical and policy priority as we continue to confront the threat of Omicron and other variants of the coronavirus. We discuss the central role of the pediatric healthcare team in caring for adolescent patients who disagree with their parents about vaccination.

Factors associated with reluctancy to acquire COVID-19 vaccination: A cross-sectional study in Shiraz, Iran, 2022

BACKGROUND

Vaccination is a crucial action that can end the COVID-19 pandemic and reduce its detrimental effect on public health. Despite the availability of various vaccines, this study was conducted to better understand the factors behind individuals refusing to get vaccinated.

METHOD

The current cross-sectional study was conducted with individuals above 18 years of age in Shiraz, Iran, who were eligible but refused to receive the COVID-19 vaccination. Demographic features and factors related to their hesitancy and willingness to participate in the vaccination program were recorded in a questionnaire.

RESULT

Out of 801 participants in the current study, 427 (53.3%) were men, with a mean age of 37.92 years (± 14.16). The findings revealed that 350 (43.7%) participants claimed the side effects of the vaccine outweigh the benefits as one reason for their reluctance toward COVID-19 vaccination, followed by the unknown efficacy of vaccines (40.4%) and a lack of trust in vaccine companies (32.8%). Ensuring the safety of the vaccine (43.7%) and verifying its effectiveness (34.5%) were the most prevalent factors behind participating in the vaccination program. Those who reported their socio-economic status as low were significantly reluctant toward vaccination because of a self-presumption of high immunity (p-value < 0.001), the unclear efficacy of vaccines (p-value < 0.001), the side effects outweighing the benefits of vaccines (p-value < 0.001), distrust of vaccine companies (p-value < 0.001), usage of mask, gloves, and sanitizers (p-value < 0.001), contradictory speech of health authorities regarding vaccines (p-value = 0.041), and the unavailability of trusted vaccines (p-value = 0.002). It should also be noted that participants reported a greater likelihood to obtain information about vaccination reluctance from family and friends (p-value <0.001) and complementary medicine professionals (p-value <0.001).

CONCLUSION

Avoiding vaccination is an undeniable public and individual health concern in Iran, as demonstrated in the current study. Concern about vaccine efficacy and side effects is the most reported cause of vaccination reluctance among individuals, which could be altered by emphasizing mass education and averting an infodemic by forming dedicated multidisciplinary organizations.

Determinants of COVID-19 vaccine uptake among healthcare professionals and the general population in Cyprus: A web-based cross-sectional survey

OBJECTIVE

This study aims to examine the factors influencing COVID-19 vaccine uptake among healthcare professionals (HCPs) and the general population in Cyprus.

METHODS

A web-based cross-sectional study was conducted (November 2021-January 2022), using a self-administered, anonymous questionnaire to collect information covering a wide range of potential determinants including sociodemographic and health-related characteristics, trust in the healthcare system, satisfaction with it, utilization of preventive healthcare services, COVID-19 vaccination information and general vaccination knowledge.

RESULTS

A total of 2582 participants completed the survey. Overall, 53.5% of participants representing the general population, and 70.0% of the HCPs received the COVID-19 vaccination. We found that as the age increases by 1 year among the general population, the odds of being vaccinated against COVID-19 increase by 1.02 units (95% 1.00, 1.03, p= 0.035). In addition, participants among the general population with increased trust in national healthcare authorities' guidelines (OR = 3.96, 95% CI: 3.41, 4.61), and increased vaccination knowledge scores (OR = 1.11, 95% CI: 1.05, 1.18) were significantly more likely to be vaccinated, while those who had underage children living in the household were significantly less likely to be vaccinated against COVID-19 (OR = 0.68, 95% CI: 0.50, 0.91). Furthermore, male HCPs (OR = 1.91, 95% CI: 1.01, 3.59), and those who reported increased trust in national healthcare authorities' guidelines (OR = 5.38, 95% CI: 3.65, 7.95) were significantly more likely to be vaccinated.

CONCLUSION

Public health policymakers can use national campaigns and long-term planning to build public trust in national healthcare authorities and raise awareness about the benefits of vaccination. Such strategies could pave the way for adequate vaccine uptake and prepare the public for unfavourable scenarios, such as future pandemics.

Understanding Vaccine Perceptions and Willingness to Receive COVID-19 Vaccination: Opportunities to Strengthen Public Health Responses and COVID-19 Services for People Who Use Drugs

Background: People who use drugs (PWUD) are at high risk for COVID-19 infection, morbidity, and mortality. COVID-19 vaccines are safe and effective at reducing serious illness and death from COVID-19. There are sparse data on the perceptions and willingness of PWUD to receive COVID-19 vaccination. Materials and Methods: In order to assess the perceptions of, and willingness to receive, COVID-19 vaccination among PWUD, we conducted a rapid survey-based assessment of 100 PWUD in NYC (Spring 2021) who reported not having received COVID-19 vaccination and who reported past 30-day illicit drug use. Results: More than 80% of respondents agreed that personally receiving a COVID-19 vaccine was important for the health of others in the community, and endorsing this belief was significantly associated with COVID-19 vaccine willingness reflecting a high prevalence of altruistic beliefs (p-value: 0.01). Other reported perceptions that were significantly associated with COVID-19 vaccine willingness were believing that COVID-19 vaccines are safe for PWUD and trusting COVID-19 information from their healthcare providers (p-values < 0.05). That said, 62% reported being unwilling to receive a COVID-19 vaccine, and 70−83% had concerns about general vaccine safety/efficacy. Examining pairs of questions to explore potential ambivalence between vaccine endorsement and vaccine concerns identified that 56−65% simultaneously reported vaccine safety/efficacy concerns and beliefs that vaccination was an important intervention. Of the 75 respondents who reported past 30-day use of harm reduction and/or substance use disorder (SUD) programs, nearly 90% reported these programs as trusted sources of COVID-19 information. Conclusion: Most participants reported altruistic beliefs about the role of vaccines for community health, including COVID-19 vaccines, and this altruism was associated with willingness to be vaccinated against COVID-19. These findings suggest a complex relationship between beliefs about the role of vaccination in community health and the safety/efficacy of vaccines; this ambivalence suggests that COVID-19 vaccine willingness may not be firmly fixed, indicating potential opportunities to address questions and build vaccine confidence. Harm reduction and SUD programs could be leveraged to further engage PWUD in receipt of COVID-19 information and/or vaccination. Recognizing vaccine ambivalence, emphasizing collective and individual benefits of vaccination, and messaging from trusted sources may be promising approaches to increase vaccination in this population.

A Multifaceted Campaign to Combat COVID-19 Misinformation in the Hispanic Community

At the height of the COVID-19 pandemic, the Public Good Projects, Hispanic Communications Network and World Voices Media joined forces to launch a nationwide, multifaceted campaign which aimed to increase vaccine confidence and decrease misinformation on social media within Hispanic communities. We created a Spanish vaccine misinformation tracking system to detect and assess misinformation circulating in online Spanish conversations. We used our media monitoring findings to work with Hispanic social media (SM) influencers, volunteers, and celebrities to spread pro-vaccine messaging online. We created misinformation-responsive SM assets, newsletters, talking points and trainings for Hispanic-serving community-based organizations (CBOs) to help them respond to misinformation and increase vaccine uptake. We used our misinformation findings to inform the creation of mass media communications such as radio PSAs and op-eds. In Year 1, our new Spanish monitoring system captured and organized 35 M Spanish and 212.7 M English posts about COVID-19 misinformation. We recruited 496 paid influencers, 2 Hispanic celebrities and 1,034 digital volunteers. We sent 70 newsletters to an average of 1539 CBO subscribers, containing 206 talking points and 344 resources (SM assets, toolkits, videos) in English and Spanish to support their outreach. Our radio PSAs reached 26.9 M people and the op-eds reached 2.9 M people. This project shows the proliferation of misinformation circulating in online Spanish conversations. It also shows we were effective at reaching our target audience with fact-based COVID-19 misinformation prebunk and debunk messaging.

Prevalence and Factors Associated with Caregivers’ Hesitancy in Immunizing Dependent Older Adults with COVID-19 Vaccines: A Cross-Sectional Survey

Background: Coronavirus disease 2019 (COVID-19) vaccinations have been proven to prevent hospitalization and mortality. However, some caregivers may be hesitant to authorize COVID-19 vaccination of people under their care. Our study aimed to evaluate factors associated with caregiver hesitancy to authorize vaccination of dependent older adults. Method: We conducted a cross-sectional telephone survey of vaccine hesitancy among caregivers of dependent older patients in the geriatric clinic of Ramathibodi Hospital. Caregivers were contacted and interviewed by trained interviewers from 20 June to 25 July 2021. Results: The study enrolled 318 participants with a mean age of 55.9 years. The majority of the participants were the patients’ children (86.5%). In total, 39.9% of participants were hesitant to authorize COVID-19 vaccination of the older adults under their care. Factors associated with caregiver vaccine hesitation were uneasiness, anxiety, agitation, sadness, and worry in association with social distancing, refusal to receive a COVID-19 vaccine, and concern about vaccine manufacturers. Conclusion: The prevalence of caregiver hesitancy to allow older adults to undergo COVID-19 vaccination was relatively high, and several factors associated with this vaccine hesitancy were identified. These findings may aid efforts toward COVID-19 vaccination of dependent older adults.

A Scoping Review of Three Dimensions for Long-Term COVID-19 Vaccination Models: Hybrid Immunity, Individual Drivers of Vaccinal Choice, and Human Errors

The virus that causes COVID-19 changes over time, occasionally leading to Variants of Interest (VOIs) and Variants of Concern (VOCs) that can behave differently with respect to detection kits, treatments, or vaccines. For instance, two vaccination doses were 61% effective against the BA.1 predominant variant, but only 24% effective when BA.2 became predominant. While doses still confer protection against severe disease outcomes, the BA.5 variant demonstrates the possibility that individuals who have received a few doses built for previous variants can still be infected with newer variants. As previous vaccines become less effective, new ones will be released to target specific variants and the whole process of vaccinating the population will restart. While previous models have detailed logistical aspects and disease progression, there are three additional key elements to model COVID-19 vaccination coverage in the long term. First, the willingness of the population to participate in regular vaccination campaigns is essential for long-term effective COVID-19 vaccination coverage. Previous research has shown that several categories of variables drive vaccination status: sociodemographic, health-related, psychological, and information-related constructs. However, the inclusion of these categories in future models raises questions about the identification of specific factors (e.g., which sociodemographic aspects?) and their operationalization (e.g., how to initialize agents with a plausible combination of factors?). While previous models separately accounted for natural- and vaccine-induced immunity, the reality is that a significant fraction of individuals will be both vaccinated and infected over the coming years. Modeling the decay in immunity with respect to new VOCs will thus need to account for hybrid immunity. Finally, models rarely assume that individuals make mistakes, even though this over-reliance on perfectly rational individuals can miss essential dynamics. Using the U.S. as a guiding example, our scoping review summarizes these aspects (vaccinal choice, immunity, and errors) through ten recommendations to support the modeling community in developing long-term COVID-19 vaccination models.

Factors associated with reversals of COVID-19 vaccination willingness: Results from two longitudinal, national surveys in Japan 2021-2022

BACKGROUND

Research characterizing changes of heart with respect to vaccine intention is scarce, and very little research considers those who were initially vaccine willing but became hesitant. Here, we sought to assess the factors related to reversals of vaccine willingness.

METHODS

We conducted a longitudinal, national survey on vaccination intention among Japanese adults aged 20 years or older, with the first questionnaire performed in February-March 2021 (N = 30,053) and the follow-up in February 2022 (N = 19,195, response rate 63.9%). The study population comprised those who reported vaccine willingness in the first survey, with the outcome variable being development of vaccine hesitancy at follow-up. We performed a regression analysis of vaccination status using sociodemographic, health-related, psychologic/attitudinal, and information-related variables as predictors. We used the sparse group minimax concave penalty (MCP) to select the optimum group of covariates for the logistic regression.

FINDINGS

Of 11,118 (57.9%) respondents who previously expressed interest in vaccination, 10,684 (96.1%) and 434 (3.9%) were in the vaccine willing and hesitant groups, respectively. Several covariates were found to significantly predict vaccine hesitancy, including marital status, influenza vaccine history, COVID-19 infection/testing history, engagement in COVID-19 preventive measures, perceived risks/benefits of the COVID-19 vaccine, and attitudes regarding vaccination policies and norms. The use of certain information sources was also associated with vaccine hesitancy.

INTERPRETATION

Sociodemographic, health-related, psychologic/attitudinal, and information-related variables predicted the development of vaccine hesitancy among those with prior willingness. Most of these predictors were also associated with vaccination status.

FUNDING

The present work was supported in part by a grant from the Kanagawa Prefectural Government of Japan and by AIST government subsidies.

Spatial clustering in vaccination hesitancy: The role of social influence and social selection

The phenomenon of vaccine hesitancy behavior has gained ground over the last three decades, jeopardizing the maintenance of herd immunity. This behavior tends to cluster spatially, creating pockets of unprotected sub-populations that can be hotspots for outbreak emergence. What remains less understood are the social mechanisms that can give rise to spatial clustering in vaccination behavior, particularly at the landscape scale. We focus on the presence of spatial clustering, and aim to mechanistically understand how different social processes can give rise to this phenomenon. In particular, we propose two hypotheses to explain the presence of spatial clustering: (i) social selection, in which vaccine-hesitant individuals share socio-demographic traits, and clustering of these traits generates spatial clustering in vaccine hesitancy; and (ii) social influence, in which hesitant behavior is contagious and spreads through neighboring societies, leading to hesitant clusters. Adopting a theoretical spatial network approach, we explore the role of these two processes in generating patterns of spatial clustering in vaccination behaviors under a range of spatial structures. We find that both processes are independently capable of generating spatial clustering, and the more spatially structured the social dynamics in a society are, the higher spatial clustering in vaccine-hesitant behavior it realizes. Together, we demonstrate that these processes result in unique spatial configurations of hesitant clusters, and we validate our models of both processes with fine-grain empirical data on vaccine hesitancy, social determinants, and social connectivity in the US. Finally, we propose, and evaluate the effectiveness of two novel intervention strategies to diminish hesitant behavior. Our generative modeling approach informed by unique empirical data provides insights on the role of complex social processes in driving spatial heterogeneity in vaccine hesitancy.

A novel household-based patient outreach pilot program to boost late-season influenza vaccination rates during the COVID-19 pandemic

Background

The objective of this study was to test a novel household‐based approach to improve late‐season influenza vaccine uptake during the 2020–2021 season, using Epic's MyChart patient portal messages and/or interactive voice response telephone calls.

Methods

This study was a non‐blinded, quality improvement program using a block randomized design conducted among patients from Reliant Medical Group clinics residing in a traditional household (≥2 individuals clinically active in the Reliant system living at the same address). Households were randomized 1:1:1 into intervention arms: non‐tailored communication (messaging based on CDC's seasonal influenza vaccination campaign), tailored communication (comprehensive communication including reinforcement of the importance of influenza vaccination for high‐risk individuals), and standard‐of‐care control. Influenza vaccination during the program was captured via medical records, and the odds of vaccination among communication arms versus the control arm were assessed. A survey assessing influenza vaccination drivers was administered using MyChart.

Results

Influenza vaccination increased by 3.3% during the program period, and no significant differences in vaccination were observed in intervention arms relative to the control arm. Study operationalization faced substantial challenges related to the concurrent COVID‐19 pandemic. Compared with vaccinated survey respondents, unvaccinated respondents less frequently reported receiving a recommendation for influenza vaccination from their healthcare provider (15.8% vs. 42.3%, p < 0.001) or awareness that vaccination could protect themselves and higher risk contacts (82.3% vs. 92.6%, p < 0.001).

Conclusions

No significant effects of the interventions were observed. Survey results highlighted the importance of healthcare provider recommendations and the need for increased education around the benefits of vaccination.

Development and implementation of an online community as a strategy for mixed methods research during a pandemic

Conducting mixed methods research is critical for healthcare researchers to understand attitudes, behaviors, and experiences on health-related topics, such as vaccine acceptance. As the COVID-19 pandemic has made it difficult to employ traditional, face-to-face qualitative methodologies, this paper describes the use of a virtual platform to conduct person-centered research. To overcome these challenges and better understand the attitudes and behaviors of vaccine-eligible individuals in the United States, an online health community called the Virtual Engagement Research Community (VERC) was designed and implemented. Using the Health Belief Model as a framework, the VERC employed a mixed methods approach to elicit insights, which included discussion topics, rapid polls, and surveys. Throughout the initial enrollment period of April-October 2021, continuous improvement efforts were made to bolster recruitment and member engagement. This agile research strategy was successful in utilizing mixed methods to capture community sentiments regarding vaccines. While this community focused on vaccination, the methodology holds promise for other areas of health research such as obesity, HIV, mental health disorders, and diabetes.