Changes in COVID-19 Vaccine Intent From April/May to June/July 2021

Knowledge, attitudes, and intentions regarding COVID-19 vaccination in the general population and the effect of different framing messages for a brief video on intentions to get vaccinated among unvaccinated individuals in the United States during July 2021

OBJECTIVE

To identify knowledge, attitudes, and beliefs (KABs) associated with COVID-19 vaccination intentions and assess the impact of vaccine-promoting messages on vaccination intentions.

METHODS

Our nationally representative survey measured KABs of COVID-19 vaccination and incorporated a randomized experiment to assess the impact of different framing messages for a video encouraging vaccination intentions among unvaccinated adults in the US. Multivariable multinomial logistic regression models were fitted to investigate the relationships of KABs, trust in public health authorities (PHAs), and vaccine confidence with vaccination intentions. Difference-in-difference estimation was conducted to assess the impact of framing messages for a video on unvaccinated individuals' vaccination intentions.

RESULTS

We observed that people with increasingly favorable vaccine KABs, trust in PHAs, and vaccine confidence were more likely to be vaccinated or intend to get vaccinated against COVID-19. Difference-in-difference estimates indicated a positive impact of exposure to the video on vaccination intentions while framing messages in some cases appeared to lower vaccination intentions. Associations between the video and vaccination intentions were more pronounced among Black/African American and Hispanic/Latinx populations and Democrats; however, associations did not vary by trust in PHAs or vaccine confidence.

CONCLUSION

Videos that encourage people to get vaccinated may provide an efficient approach to nudge vaccine-hesitant individuals towards getting vaccinated. However, framing messages may negatively impact vaccination intentions and need to be developed carefully.

PRACTICE IMPLICATIONS

This study provides solid experimental evidence for the importance of tailoring message framing to the characteristics and experience of the audience, while cautioning potential negative impacts of framing that does not match its intended audience. Our findings are applicable to health communication strategies on the population level, such as mass media campaigns, and the use of framing for messages to encourage vaccination but may also be informative for healthcare professionals consulting hesitant individuals about COVID-19 vaccinations.

Factors associated with vaccination intention and uptake over time in a sample of older Australians

This study sought to identify the behavioural and social drivers of vaccination in 16,745 older Australians. We analysed and compared influences on COVID-19 vaccination intention and uptake using prospectively collected survey data from the Sax Institute's 45 and Up Study. Vaccination intention increased with older age (adjusted odds ratio [aOR]:1.03; 95 % confidence interval [CI]: 1.01-1.04; p = .002), a belief that the vaccine is important for the person's own health (aOR: 5.17; 95 % CI: 4.23-6.24; p < .001), is safe (aOR:2.64; 95 % CI: 2.19-3.2; p < .001), and trusted by the person (aOR:6.79; 95 % CI: 5.59-8.26 p < .001); concern about contracting COVID-19 (aOR:1.78; 95 % CI: 1.47-2.17; p < .001); having enough information about COVID-19 vaccines (aOR:1.99; 95 % CI: 1.65-2.29; p < .001); a belief that most adults will receive a COVID-19 vaccine (aOR:2.31; 95 % CI: 1.93-2.77; p < .001); and a belief that family and friends wanted the person to receive a COVID-19 vaccine (aOR:6.07; 95 % CI: 5.06-7.27; p < .001). The same factors contributed to increased vaccine uptake, with the exception of age and the belief that the person had enough information about the vaccine. Concern that the vaccine will cause a serious reaction was associated with both lower intention (aOR:0.35; 95 % CI: 0.29-0.43; p < .001) and lower uptake (aOR:0.61; 95 % CI: 0.46-0.81; p < .001) while lower intention was also associated with low decisional autonomy (aOR:0.37; 95 % CI: 0.22-0.62; p < .001). Intentions changed over time and a change towards vaccination was associated with perceptions of vaccine safety. Access barriers played a role in the non-vaccination of otherwise intending older Australians. Messaging that is adaptive to safety concerns, emphasises vaccine benefits, leverages social norms, and targets people who make decisions for older Australians may be helpful for influencing vaccination intentions and increasing vaccine uptake.

Acceptance of Seasonal Influenza Vaccine Following COVID-19 Vaccination: A Survey among Israel Defense Forces Soldiers

Data regarding the contribution of COVID-19 vaccine rollouts to real-world uptake of influenza vaccination remains unclear. This cross-sectional survey-based study among Israel Defense Forces (IDF) soldiers aimed to assess the impact of the COVID-19 pandemic and specifically, previous COVID-19 vaccines uptake, on the intention to vaccinate for influenza during 2021-2022 season. Participants engaged in an online survey addressing vaccination history and current vaccine-related preferences. The survey was delivered prior to the initiation of the IDF's annual influenza immunization campaign. A multinomial logistic regression model was applied to analyze factors correlated with unwillingness to receive influenza vaccine. Overall, 825 invitations to participate in the survey were distributed and the overall response rate was 78.5%. Among the 648 participants who replied (61.6% males, median age of 20 years), 51.9% were willing to receive the upcoming influenza vaccine. Factors associated with vaccine reluctance included being female, not receiving the previous season's influenza vaccine, not having a previous diagnosis of COVID-19, and having decreased uptake of COVID-19 vaccines. Among participants not intending to receive an influenza vaccine, 50.3% stated that they are healthy and have no need for the vaccine and 36.2% stated they received too many vaccines over the previous year. The results of this study may suggest that influenza vaccination rates in the post-COVID-19 vaccine era may be reduced due to a perceived "vaccine saturation" phenomenon, owing to the density of COVID-19 vaccine administration. Future interventions such as campaigns related to maximizing influenza vaccination coverage should address repeated doses of COVID-19 vaccine administration.

How does the vaccine approval procedure affect COVID-19 vaccination intentions?

People's willingness to vaccinate is critical to combating the COVID-19 pandemic. We devise a representative experiment to study how the design of the vaccine approval procedure affects trust in newly developed vaccines and consequently public attitudes towards vaccination. Compared to an Emergency Use Authorization, choosing the more thorough Conditional Marketing Authorization approval procedure increases vaccination intentions by 13 percentage points. The effects of the increased duration of the approval procedure are positive and significant only for Emergency Use Authorization. Treatment effects do not differ between relevant subgroups, such as respondents who had (did not have) COVID-19, or between vaccinated and unvaccinated respondents. Increased trust in the vaccine is the key mediator of treatment effects on vaccination intentions.

From COVID-19 Vaccine Hesitancy to Vaccine Acceptance: Results of a Longitudinal Survey

OBJECTIVES

COVID-19 vaccines are widely available, but uptake is suboptimal. To develop strategies to increase vaccination rates, we sought to (1) characterize adults initially hesitant to be vaccinated for COVID-19 who later received the vaccine and (2) identify factors associated with their vaccination decision.

METHODS

In January 2021, we conducted an online survey of US adults via Prolific that assessed vaccination intent, COVID-19-related knowledge and attitudes, and demographic characteristics. In May 2021, we recontacted respondents to assess vaccination status and factors influencing their vaccination decision. We used χ² statistics and t tests to examine associations between respondents' vaccination status and their characteristics, knowledge, and attitudes. We analyzed reasons for vaccination using thematic analysis.

RESULTS

Of 756 initially vaccine-hesitant respondents, 529 (70.0%) completed the follow-up survey. Nearly half of those initially not sure about vaccination (47.3%, 112 of 237) were vaccinated at follow-up, while 21.2% (62 of 292) of those initially planning not to be vaccinated were vaccinated at follow-up. Of those initially not sure, higher educational attainment, greater knowledge of COVID-19, and a doctor's recommendation were associated with vaccination. Of those initially intending not to be vaccinated, male sex, Democratic political affiliation, receipt of an influenza shot within 5 years, being more worried about COVID-19, and having greater COVID-19 knowledge were associated with increased likelihood of being vaccinated. Of 167 respondents who gave reasons for vaccination, protecting oneself and others (59.9%), practical issues (29.9%), social influences (17.4%), and vaccine safety (13.8%) were the main reasons.

CONCLUSION

Providing information on the protective value of vaccination, implementing rules that make remaining unvaccinated burdensome, making vaccination easy, and providing social support may influence vaccine-hesitant adults to accept vaccination.

Changes in COVID-19 Vaccine Intent Among a Diverse Population of Older Adults, June 2021-February 2022

Introduction COVID-19 vaccination rates remain suboptimal in the United States. Clinicians and policymakers need to better understand how likely vaccine-hesitant individuals are to ultimately accept vaccination and what is associated with such changes. This study's aims were to 1) describe changes between vaccine intentions and actual uptake from June 2021 through February 2022, and 2) identify modifiable factors associated with vaccine uptake among those with initial hesitancy. Methods This cohort study included a stratified random sample of adults aged 65 years and older in an integrated health care system. The survey, conducted June through August 2021, elicited intent and perceptions regarding COVID-19 vaccination. Subsequent vaccine uptake through February 2022 was analyzed using electronic health records. Results Of 1195 individuals surveyed, 66% responded; 213 reported not yet having received a COVID-19 vaccine and were further analyzed. At baseline, most individuals said they would definitely not (42%) or probably not (5%) get the COVID-19 vaccine or were not sure (26%). During follow-up, 61 individuals (29%) were vaccinated, including 19% of those who initially said they would definitely not be vaccinated. Among vaccine-hesitant individuals, the rate of vaccination was highest for those who initially considered COVID-19 less dangerous than the vaccine (46%) or named short-term side effects (36%) as their most important concern. Conclusions COVID-19 vaccine intent among older adults was malleable during the pandemic's second year, even among those who initially said they would definitely not be vaccinated. Vaccine uptake could be enhanced by increasing awareness of COVID-19 risks and by addressing vaccine side effects.

Assessing the Impact of COVID-19 Phased Vaccine Eligibility on COVID-19 Vaccine Intent among African Americans in Southeastern Louisiana: A Community-Based, Cohort Study

The purpose of this study was to explore the impact of eligibility for the coronavirus 2019 (COVID-19) vaccine at the time of the vaccine rollout as a predictor of vaccine intent within the African American community.

METHODS

Four hundred eighty-seven African American participants in southeastern Louisiana were surveyed from January-April of 2021, with follow-up surveys occurring in Fall 2021. Survey domains included demographics, vaccine hesitancy, discrimination in the healthcare setting, and knowledge and experiences with COVID-19. Descriptive statistics, Chi-square tests, and binary logistic regression were performed.

RESULTS

Participants eligible for the vaccine were 1.61 times as likely to express positive vaccine intent versus ineligible participants. Additional predictors of vaccine intent were age, insurance status and coverage, and female sex at birth. In the multivariable logistic analysis, eligible individuals were 2.07 times as likely to receive the vaccine versus ineligible individuals.

CONCLUSIONS

Vaccine eligibility for the COVID-19 vaccine was a significant predictor of intent to vaccinate in the African American community. Younger individuals were less likely to have a positive intent, correlating with the eligibility of ages 16+ occurring 5 months post-vaccine approval.

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.

Characterising reasons for reversals of COVID-19 vaccination hesitancy among Japanese people: One-year follow-up survey

BACKGROUND

Vaccine hesitancy is a global public health threat. We present unique data that characterises those who experienced reversals of COVID-19 vaccination hesitancy in Japan.

METHODS

We administered a questionnaire on vaccination intention among 30053 Japanese adults aged 20 years or older before the COVID-19 vaccination was available to the general population (first survey) and conducted a follow-up survey on vaccination status one year later in February 2022 (second survey). Those who responded in the first survey that they did not intend to be vaccinated or were unsure and then responded in the second survey that they were vaccinated or intend to be vaccinated were asked about the reasons for their change of heart. Based on previous literature and expert opinion, 31 reasons for changing vaccination intention were compiled and respondents were asked to choose which among them applied to themselves, with multiple responses possible. Based on the results of those responses, each individual was then clustered using the Uniform Manifold Approximation and Projection (UMAP) dimensionality reduction technique and Ordering Points To Identify the Clustering Structure (OPTICS) algorithm. We then identified unique characteristics among each of the sub-populations (clusters).

FINDINGS

In the second survey we received 19195 responses (response rate 63.9%), of which 8077 responded 'no' or 'not sure' in the first survey regarding their intention to be vaccinated. Of these, 5861 responded having received or intending to receive the vaccine (72.6%). We detected six and five sub-populations (clusters) among the 'no' group and 'not sure' group, respectively. The clusters were characterized by perceived benefits of vaccination, including the COVID-19 vaccine, awareness of the COVID-19 vaccination status of those close to them, recognition of the social significance of COVID-19 vaccination for the spread of infection, and dispelled concerns about short-term adverse reactions and the safety of the COVID-19 vaccine. Work and personal relationship reasons were also found to be a unique overarching reason for vaccination changes of heart only among those who did not intend to vaccinate.

INTERPRETATION

Those who changed their intention to accept COVID-19 vaccination as well as their unique characteristics as detailed in this study will be important entry points when discussing how to promote vaccination to those who are hesitant to vaccinate in the future.

FUNDING

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

Understanding change in COVID-19 vaccination intention with network analysis of longitudinal data from Dutch adults

Prior research into the relationship between attitudes and vaccination intention is predominantly cross-sectional and therefore does not provide insight into directions of relations. During the COVID-19 vaccines development and enrollment phase, we studied the temporal dynamics of COVID-19 vaccination intention in relation to attitudes toward COVID-19 vaccines and the pandemic, vaccination in general, social norms and trust. The data are derived from a longitudinal survey study with Dutch participants from a research panel (N = 744; six measurements between December 2020 and May 2021; age 18–84 years [M = 53.32]) and analyzed with vector-autoregression network analyses. While cross-sectional results indicated that vaccination intention was relatively strongly related to attitudes toward the vaccines, results from temporal analyses showed that vaccination intention mainly predicted other vaccination-related variables and to a lesser extent was predicted by variables. We found a weak predictive effect from social norm to vaccination intention that was not robust. This study underlines the challenge of stimulating uptake of new vaccines developed during pandemics, and the importance of examining directions of effects in research into vaccination intention.

Short-sighted decision-making by those not vaccinated against COVID-19

Widespread vaccination is necessary to minimize or halt the effects of many infectious diseases, including COVID-19. Stagnating vaccine uptake can prolong pandemics, raising the question of how we might predict, prevent, and correct vaccine hesitancy and unwillingness. In a multinational sample (N = 4,452) recruited from 13 countries that varied in pandemic severity and vaccine uptake (July 2021), we examined whether short-sighted decision-making as exemplified by steep delay discounting-choosing smaller immediate rewards over larger delayed rewards-predicts COVID-19 vaccination status. Delay discounting was steeper in unvaccinated individuals and predicted vaccination status over and above demographics or mental health. The results suggest that delay discounting, a personal characteristic known to be modifiable through cognitive interventions, is a contributing cause of differences in vaccine compliance.

COVID-19 Vaccination Status, Attitudes, and Values among US Adults in September 2021

Background: The Delta COVID-19 variant caused a resurgence in cases and deaths during the summer of 2021, particularly among the unvaccinated, highlighting the need to increase vaccine coverage. We describe a survey conducted in September 2021, in the midst of the Delta variant surge, after the FDA fully approved Pfizer-BioNTech’s vaccine for ages 16+ and issued an emergency use authorization for ages 12−15. Methods and Findings: US adults were surveyed to measure COVID-19 vaccination status, intentions, attitudes, values, and trust in public health authorities. More than three-quarters (77%) reported receiving at least one dose of COVID-19 vaccination. Of the unvaccinated, 6% intended to vaccinate, 40% were unlikely to ever vaccinate, and 55% remained uncertain. Most of the unvaccinated were <45 years old (62%), without a bachelor’s degree (83%), earning less than $85,000 annually (74%), and Republican/Independent (66%). Concerns among the unvaccinated-yet-still-uncertain included the vaccines’ safety (86%), speed of development (86%), and suspicion of government (79%) and pharmaceutical companies (69%). Most (86%) of the unvaccinated reported they would not vaccinate if mandated by their employer. About one third (34%) of the unvaccinated reported facing at least one barrier to vaccination. Conclusion: More than half of unvaccinated adults remained uncertain about COVID-19 vaccination, indicating an opportunity to support their decision making. Public health must increase easy and equitable access to vaccination and renew efforts to provide unvaccinated populations access to information from trusted sources.

Effect of Electronic and Mail Outreach From Primary Care Physicians for COVID-19 Vaccination of Black and Latino Older Adults: A Randomized Clinical Trial

IMPORTANCE

COVID-19 morbidity is highest in Black and Latino older adults. These racial and ethnic groups initially had lower vaccination uptake than others, and rates in Black adults continue to lag.

OBJECTIVES

To evaluate the effect of outreach via electronic secure messages and mailings from primary care physicians (PCPs) on COVID-19 vaccination uptake among Black and Latino older adults and to compare the effects of culturally tailored and standard PCP messages.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial was conducted from March 29 to May 20, 2021, with follow-up surveys through July 31, 2021. Latino and Black individuals aged 65 years and older from 4 Kaiser Permanente Northern California (KPNC) service areas were included. Data were analyzed from May 27, 2021, to September 28, 2021.

INTERVENTIONS

Individuals who had not received COVID-19 vaccination after previous outreach were randomized to electronic secure message and/or mail outreach from their PCP, similar outreach with additional culturally tailored content, or usual care. Outreach groups were sent a secure message or letter in their PCP's name, followed by a postcard to those still unvaccinated after 4 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was time to receipt of COVID-19 vaccination during the 8 weeks after initial study outreach. KPNC data were supplemented with state data from external sources. Intervention effects were evaluated via proportional hazards regression.

RESULTS

Of 8287 included individuals (mean [SD] age, 72.6 [7.0] years; 4665 [56.3%] women), 2434 (29.4%) were Black, 3782 (45.6%) were Latino and preferred English-language communications, and 2071 (25.0%) were Latino and preferred Spanish-language communications; 2847 participants (34.4%) had a neighborhood deprivation index at the 75th percentile or higher. A total of 2767 participants were randomized to culturally tailored PCP outreach, 2747 participants were randomized to standard PCP outreach, and 2773 participants were randomized to usual care. Culturally tailored PCP outreach led to higher COVID-19 vaccination rates during follow-up compared with usual care (664 participants [24.0%] vs 603 participants [21.7%]; adjusted hazard ratio (aHR), 1.22; 95% CI, 1.09-1.37), as did standard PCP outreach (635 participants [23.1%]; aHR, 1.17; 95% CI, 1.04-1.31). Individuals who were Black (aHR, 1.19; 95% CI, 1.06-1.33), had high neighborhood deprivation (aHR, 1.17; 95% CI, 1.03-1.33), and had medium to high comorbidity scores (aHR, 1.19; 95% CI, 1.09-1.31) were more likely to be vaccinated during follow-up.

CONCLUSIONS AND RELEVANCE

This randomized clinical trial found that PCP outreach using electronic and mailed messages increased COVID-19 vaccination rates among Black and Latino older adults.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05096026.

Deep-seated psychological histories of COVID-19 vaccine hesitance and resistance

To design effective pro-vaccination messaging, it is important to know “where people are coming from”—the personal experiences and long-standing values, motives, lifestyles, preferences, emotional tendencies, and information-processing capacities of people who end up resistant or hesitant toward vaccination. We used prospective data from a 5-decade cohort study spanning childhood to midlife to construct comprehensive early-life psychological histories of groups who differed in their vaccine intentions in months just before COVID vaccines became available in their country. Vaccine-resistant and vaccine-hesitant participants had histories of adverse childhood experiences that foster mistrust, longstanding mental-health problems that foster misinterpretation of messaging, and early-emerging personality traits including tendencies toward extreme negative emotions, shutting down mentally under stress, nonconformism, and fatalism about health. Many vaccine-resistant and -hesitant participants had cognitive difficulties in comprehending health information. Findings held after control for socioeconomic origins. Vaccine intentions are not short-term isolated misunderstandings. They are part of a person’s style of interpreting information and making decisions that is laid down before secondary school age. Findings suggest ways to tailor vaccine messaging for hesitant and resistant groups. To prepare for future pandemics, education about viruses and vaccines before or during secondary schooling could reduce citizens’ level of uncertainty during a pandemic, and provide people with pre-existing knowledge frameworks that prevent extreme emotional distress reactions and enhance receptivity to health messages. Enhanced medical technology and economic resilience are important for pandemic preparedness, but a prepared public who understands the need to mask, social distance, and vaccinate will also be important.

Factors Affecting Young Adults’ Decision Making to Undergo COVID-19 Vaccination: A Patient Preference Study

Young adults are a substantial driver of lagging vaccination against COVID-19 worldwide. We aimed to understand what vaccine or vaccination environment attributes may affect young adults’ vaccine inclination. We contacted a convenience sample of 1415 students to recruit a minimum of 150 individuals for a web-based discrete choice experiment. The respondents were asked to choose one of two hypothetical vaccines, defined by six attributes—vaccine efficacy, risk of mild side effects, protection duration, administration route, recommender, and travel time to the vaccination site. Individual preferences were calculated with the Markov chain Monte Carlo hierarchical Bayes estimation. A total of 445 individuals (mean age 24.4 years, 272 (61.1%) women) completed the survey between 22 March and 3 May 2021. Vaccine protection duration (28.3 (95% CI, 27.0–29.6)) and vaccine efficacy in preventing COVID-19 (27.5 (95% CI, 26.3–28.8)) were the most important, followed by the risk of vaccine side effects (17.3 (95% CI, 16.2–18.4)). Individuals reluctant or unsure about vaccination (21.1%) prioritized the potential for mild side effects higher and vaccine efficacy lower than the vaccine-inclined individuals. New vaccination programs that target young adults should emphasize the protection duration, low risk of vaccine side effects, and high efficacy.