COVID-19 vaccine acceptance: A comparative longitudinal analysis of the association between risk perception, confidence, and the acceptance of a COVID-19 vaccine

Following the outbreak of COVID-19, scientists rushed to develop vaccines to protect individuals and ferry the world out of the pandemic. Unfortunately, vaccine hesitancy is a major threat to the success of vaccination campaigns. Research on previous pandemics highlighted the centrality of perceived risk and confidence as core determinants of vaccine acceptance. Research on COVID-19 is less conclusive, and frequently it relies on one-country, cross-sectional data, thus making it hard to generalize results across contexts and observe these relationships over time. To bridge these gaps, in this article, we analyzed the association between perceived risk, confidence, and vaccine acceptance cross-sectionally at individual and country levels. Then, we longitudinally explored whether a within-country variation in perceived risk and confidence was correlated with a variation in vaccine acceptance. We used data from a large-scale survey of individuals in 23 countries and 19 time-points between June 2020 and March 2021 and comparative longitudinal multilevel models to estimate the associations at different levels of analysis simultaneously. Results show the existence of cross-sectional relationships at the individual and country levels but no significant associations within countries over time. This article contributes to our understanding of the roles of risk perception and confidence in COVID-19 vaccines' acceptance by underlining that these relationships might differ at diverse levels of analysis. To foster vaccine uptake, it might be important to address individual concerns and persisting contextual characteristics, but increasing levels of perceived risk and confidence might not be a sufficient strategy to increase vaccine acceptance rates.

Parental perceptions of chickenpox and the varicella vaccine: A qualitative systematic review

BACKGROUND

In countries where varicella vaccination is not on the routine childhood immunisation schedule, such as those in the United Kingdom (UK), chickenpox is an almost universal disease of childhood. Chickenpox can cause serious complications, particularly in infants, pregnant women, and the immunocompromised. In November 2023 the varicella vaccine was recommended for inclusion in the UK routine childhood immunisation schedule. Successful rollout of the vaccine may be hindered by parental concerns about vaccine safety and efficacy, and perceptions of chickenpox as a mild illness.

OBJECTIVE

To examine parental perceptions of chickenpox and varicella vaccination, which may be crucial to effective vaccination campaigns.

DESIGN

Qualitative systematic review and thematic analysis.

METHODS

Six electronic databases were systematically searched for studies published between 2016 and 2023: CINAHL, EMBASE, MEDLINE, PsycInfo, PubMed, and Web of Science. The included studies were appraised against the Critical Appraisal Skills Program checklist for qualitative studies. Thematic analysis was used to analyse qualitative data, through the development of themes.

RESULTS

22 articles were included in this review, and five themes identified: perceptions that chickenpox is a mild illness, that parents have concerns about varicella vaccine efficacy and safety, a notion of natural immunity as superior, social determinants of health influence vaccine decision making, and vaccination is overwhelming perceived as a parental decision.

CONCLUSIONS

Whilst some parents displayed an acceptance and willingness to vaccinate against chickenpox, many expressed concerns, and perceived chickenpox as a routine unworrying childhood illness. Analysis demonstrated a knowledge gap in understanding UK parental opinions regarding chickenpox and varicella vaccination, highlighting the need for research in this area, particularly given ongoing reconsideration for inclusion in the UK vaccination schedule.

REGISTRATION

The review was registered on PROSPERO, registration ID CRD42021236120.

Linking cognitive and affective heuristic cues to interpersonal risk perceptions and behavior

People often use cognitive and affective heuristics when judging the likelihood of a health outcome and making health decisions. However, little research has examined how heuristics shape risk perceptions and behavior among people who make decisions on behalf of another person. We examined associations between heuristic cues and caregivers' perceptions of their child's asthma risk, the frequency of caregivers' asthma management behaviors, and child health outcomes. We used Ipsos KnowledgePanel to recruit 814 U.S. adult caregivers of children with asthma of the age <18 years. Participants completed a survey at baseline (T1) and 3 months later (T2). Caregivers who, at T1, reported greater negative affect about their child's asthma (affect heuristic cue), greater ease of imagining their child experiencing asthma symptoms (availability heuristic cue), and greater perceived similarity between their child and a child who has ever experienced asthma symptoms (representativeness heuristic cue) reported statistically significantly (p < 0.05) higher interpersonal perceived risk of their child having an exacerbation or uncontrolled asthma at T1. They also indicated at T2 that their child had poorer asthma control and more frequent exacerbations. Greater T1 negative affect was associated with more frequent T2 actions to reduce inflammation, manage triggers, and manage symptoms, and with poorer T2 child health outcomes. Heuristic cues are likely important for interpersonal-not just personal-risk perceptions. However, the interrelationship between caregivers' ratings of heuristic cues (in particular, negative affect) and risk judgments may signify a struggle with managing their child's asthma and need for extra support from health care providers or systems.

The doctor knows or the evidence shows: An online survey experiment testing the effects of source trust, pro-vaccine evidence, and dual-processing in expert messages recommending child COVID-19 vaccination to parents

Increasing child vaccination rates is a critical step toward mitigating the spread of COVID-19. Both distrust in expert sources and concern about the safety and efficacy of vaccines may contribute to parent vaccine hesitancy. The present study is the first to test the effectiveness of building trust and providing evidence supporting child COVID-19 vaccines in recommendation messages for parents. Based on dual-processing theories, emphasis on source trustworthiness and pro-vaccine evidence may each be particularly effective when the other is not present. It was hypothesized that these two approaches would have main and interaction effects on perceived message effectiveness and pro-vaccine beliefs. A between-subjects 2 (trust-building appeal vs. no trust-building appeal) X 2 (pro-vaccine evidence vs. no pro-vaccine evidence) online survey experiment was conducted in December 2021 and January 2022 with United States parents/guardians of children <18 years old (n = 401). As hypothesized, trust and pro-vaccine evidence each had significant simple main effects on both outcomes. Analysis of variance showed a significant negative interaction effect of trust and pro-vaccine evidence on perceived message effectiveness [F(3, 394) = 6.47; η2 = 0.02, p = 0.002; 95% CI (0.01, 0.11)], supporting the dual-processing hypothesis. The interaction effect on pro-vaccine beliefs was also negative but not significant [F(3, 394) = 2.69; η2 = 0.01; p = 0.102; 95% CI (0.00, 0.03)]. Either highlighting evidence supporting vaccines or building trust in expert sources can influence parent vaccine support. Messages which include strong evidence supporting recommended behaviors may influence recommendation acceptance even among those with lower trust in expert sources and establishing trust may reduce the need to describe available evidence.

Perceptions and tolerance of uncertainty: relationship to trust in COVID-19 health information and vaccine hesitancy

The COVID-19 crisis has exposed the public to considerable scientific uncertainty, which may promote vaccine hesitancy among individuals with lower tolerance of uncertainty. In a national sample of US adults in May-June 2020, we examined how both perceptions of uncertainty about COVID-19 and trait-level differences in tolerance of uncertainty arising from various sources (risk, ambiguity, and complexity) are related to vaccine hesitancy-related outcomes, including trust in COVID-19 information, COVID-19 vaccine intentions, and beliefs that COVID-19 vaccines should undergo a longer testing period before being released to the public. Overall, perceptions of COVID-19 uncertainty were not associated with trust in information, vaccine intentions, or beliefs about vaccine testing. However, higher tolerance of risk was associated with lower intentions to get vaccinated, and lower tolerance of ambiguity was associated with lower intentions to get vaccinated and preferring a longer period of vaccine testing. Critically, perceptions of COVID-19 uncertainty and trait-level tolerance for uncertainty also interacted as predicted, such that greater perceived COVID-19 uncertainty was more negatively associated with trust in COVID-19 information among individuals with lower tolerance for risk and ambiguity. Thus, although perceptions of uncertainty regarding COVID-19 may not reduce trust and vaccine hesitancy for all individuals, trait-level tolerance of uncertainty arising from various sources may have both direct and moderating effects on these outcomes. These findings can inform public health communication or other interventions to increase COVID-19 vaccination uptake.

Effects of Construal Level on Responses to Ambiguous Health Information about Alcohol Consumption

Information about the health effects of alcohol consumption can be ambiguous (i.e., lacking in reliability, credibility, or adequacy) and thus may promote maladaptive health behavior. Guided by Construal Level Theory and a conceptual taxonomy of uncertainty in health care, we tested the hypothesis that manipulating construal level would promote adaptive responses to ambiguous health information. We examined the effects of ambiguous health information about alcohol on health cognitions, message responses, and intentions, as well as whether manipulating construal moderated these effects. Alcohol users (n = 135, M_age = 20.15, 68.9% female) were randomly assigned to either a high-level or low-level construal task and then to read either an ambiguous or unambiguous health communication about the health effects of alcohol. Participants responded similarly to ambiguous health information as they did to unambiguous health information and participants in a high-level construal did not generally report differences compared with those in a low-level construal. Findings suggest that ambiguous health information might not always lead to maladaptive effects. More research is needed to examine moderators of the relationship between ambiguous health information and health outcomes, as well as to understand how and when using construal manipulations are effective in different health contexts.

The predictive role of parental attitudes toward COVID-19 vaccines and child vulnerability: A multi-country study on the relationship between parental vaccine hesitancy and financial well-being

Background and purpose

Recent new mutations and increases in transmission of COVID-19 among adolescents and children highlight the importance of identifying which factors influence parental decisions regarding vaccinating their children. The current study aims to explore whether child vulnerability and parents' attitudes toward vaccines mediate the association between perceived financial well-being and vaccine hesitancy among parents.

Method

A predictive, cross-sectional, multi-country online questionnaire was administered with a convenience sample of 6,073 parents (Australia, 2,734; Iran, 2,447; China, 523; Turkey, 369). Participants completed the Parent Attitude About Child Vaccines (PACV), the Child Vulnerability Scale (CVS), a Financial Well-being (FWB) measure, and Parental Vaccine Hesitancy (PVH) questionnaire.

Results

The current study revealed that perceived financial well-being had significant and negative associations with parents' attitudes toward COVID-19 vaccines and child vulnerability among the Australian sample. Contrary to the Australian findings, results from Chinese participants indicated that financial well-being had significant and positive predictive effects on parent attitudes toward vaccines, child vulnerability, and parental vaccine hesitancy. The results of the Iranian sample revealed that parents' attitudes toward vaccines and child vulnerability significantly and negatively predicted parental vaccine hesitancy.

Conclusion

The current study revealed that a parents' perceived financial well-being had a significant and negative relationship with parental attitudes about vaccines and child vulnerability; however, it did not significantly predict parental vaccine hesitancy among Turkish parents as it did for parents in Australia, Iran, and China. Findings of the study have policy implications for how certain countries may tailor their vaccine-related health messages to parents with low financial wellbeing and parents with vulnerable children.

A systematic literature review to clarify the concept of vaccine hesitancy

Vaccine hesitancy (VH) is considered a top-10 global health threat. The concept of VH has been described and applied inconsistently. This systematic review aims to clarify VH by analysing how it is operationalized. We searched PubMed, Embase and PsycINFO databases on 14 January 2022. We selected 422 studies containing operationalizations of VH for inclusion. One limitation is that studies of lower quality were not excluded. Our qualitative analysis reveals that VH is conceptualized as involving (1) cognitions or affect, (2) behaviour and (3) decision making. A wide variety of methods have been used to measure VH. Our findings indicate the varied and confusing use of the term VH, leading to an impracticable concept. We propose that VH should be defined as a state of indecisiveness regarding a vaccination decision.

Vaccine Hesitancy in Pediatrics

Vaccine hesitancy is a growing complex and multifaceted phenomenon. It encompasses a wide spectrum of context-dependent attitudes and beliefs. Multiple factors influence parental decision-making including knowledge, sources of information, risk perception, trust, and individual experiences among others. This review focuses on describing the most common reasons that contribute to vaccine hesitancy among parents. Social media and the Internet have been described as major elements that can negatively influence parental decision-making regarding vaccines. The next focus is describing effective interventions that clinical providers can apply. Nonconfrontational and open discussions along with trusting and strong relationships between parents and providers seem to create a solid foundation toward vaccine acceptance. In addition, motivational interviewing is a helpful tool that has proven to be effective during these discussions. Ultimately, an individualized approach tailored to a specific community will likely be most effective in addressing vaccine hesitancy.

Reporting adverse events of COVID-19 vaccines: The case of Bulgaria

As a member state of the European Union, where vaccines against COVID-19 are available and affordable, Bulgaria reports the lowest immunization coverage and the most pronounced vaccine distrust. The present study aimed to assess the self-reported adverse reactions following COVID-19 vaccination as a possible tool to increase the trust in vaccines. A cross-sectional survey-based study, covering 761 vaccinated respondents, was conducted in Plovdiv (469 with an mRNA vaccine and 292 with an adenoviral vector vaccine). Descriptive statistics parametric and non-parametric methods were applied. Statistical significance was set at p<0.05. The median age of the respondents was 42 years, females (72.5%). At least one adverse reaction was reported in 89.9% of those immunized with mRNA vaccine and 93.8% in the adenoviral vector vaccine group (p>0.05). They were mild to moderate and resolved within several days. The levels of local reactions were comparable: 91.7% in those who received mRNA and 89.7% in those who received an adenoviral vector vaccine (p = 0.366). The most common types of systemic reactions were fatigue, headache, and muscle pains. An association was found between the systemic reactions and the type of vaccine administered: 59.7% in mRNA recipients and 89.4% in adenoviral vector vaccinees (p<0.001). None of the registered systemic reactions required medical attention. There were 3 reports of generalized urticaria after an mRNA and 2 after an adenoviral vector vaccine. The reported reactions are relatively high but expected and no adverse events have been reported that are not listed in the official Summary of Product Characteristics.

Parent's risk preference and childhood vaccination: evidence from Indonesia

A vaccines advisory group to the World Health Organization (WHO) identified complacency, inconvenience in accessing vaccines, and lack of confidence as key reasons for hesitancy. In childhood vaccination, the decision to take a vaccine relies on parents' decisions. Our study explored the relationship between parents' risk aversion and complete childhood vaccination status to identify whether demand contributes to vaccine hesitancy in Indonesia. We examined risk aversion using data from the fifth-wave Indonesian Family Life Survey (IFLS), focusing on parents with extreme risk aversion or fear of uncertainty. The logistic regression shows a negligible relationship between parents' risk aversion and childhood vaccination; nevertheless, parents who fear uncertainty tend to avoid vaccination. The results of this study encourage public health professionals and policymakers to properly design vaccine campaigns with careful consideration of the risk preference dimension of the targeted beneficiaries.

Psychological Impact of Ambiguous Health Messages about COVID-19

Perceiving ambiguity in health information-that is, uncertainty elicited from believing information lacks credibility, reliability, or adequacy-is typically associated with pessimistic appraisals (e.g., high perceived disease risk) and behavioral avoidance. We examined the effect of ambiguous health information about COVID-19 on health cognitions and vaccination intentions, and tested a "normalized-uncertainty" intervention. Two studies with identical methodology (online adult sample: n = 299, undergraduate sample: n = 150) were conducted in March to April 2020. Participants were randomly assigned to read one of three health messages about COVID-19 that emphasized what was currently unknown (ambiguity condition), what was currently unknown but that scientific uncertainty is expected (intervention condition), or what was currently known (control condition). The ambiguity condition led to greater perceived ambiguity than the control condition and perceived ambiguity in the intervention condition was comparable to the ambiguity condition. There were few differences in health cognitions, and no differences in vaccination intentions, when examining pairwise comparisons across the three conditions. Correlational analyses collapsing across condition indicated evidence of pessimistic appraisal but not behavioral avoidance among individuals who perceived greater ambiguity. Future research should examine longer, more detailed normalized-uncertainty interventions.

Factors that influence parents' and informal caregivers' views and practices regarding routine childhood vaccination: a qualitative evidence synthesis

BACKGROUND

Childhood vaccination is one of the most effective ways to prevent serious illnesses and deaths in children. However, worldwide, many children do not receive all recommended vaccinations, for several potential reasons. Vaccines might be unavailable, or parents may experience difficulties in accessing vaccination services; for instance, because of poor quality health services, distance from a health facility, or lack of money. Some parents may not accept available vaccines and vaccination services. Our understanding of what influences parents' views and practices around childhood vaccination, and why some parents may not accept vaccines for their children, is still limited. This synthesis links to Cochrane Reviews of the effectiveness of interventions to improve coverage or uptake of childhood vaccination.

OBJECTIVES

- Explore parents' and informal caregivers' views and practices regarding routine childhood vaccination, and the factors influencing acceptance, hesitancy, or nonacceptance of routine childhood vaccination. - Develop a conceptual understanding of what and how different factors reduce parental acceptance of routine childhood vaccination. - Explore how the findings of this review can enhance our understanding of the related Cochrane Reviews of intervention effectiveness.

SEARCH METHODS

We searched MEDLINE, Embase, CINAHL, and three other databases for eligible studies from 1974 to June 2020.

SELECTION CRITERIA

We included studies that: utilised qualitative methods for data collection and analysis; focused on parents' or caregivers' views, practices, acceptance, hesitancy, or refusal of routine vaccination for children aged up to six years; and were from any setting globally where childhood vaccination is provided.

DATA COLLECTION AND ANALYSIS

We used a pre-specified sampling frame to sample from eligible studies, aiming to capture studies that were conceptually rich, relevant to the review's phenomenon of interest, from diverse geographical settings, and from a range of income-level settings. We extracted contextual and methodological data from each sampled study. We used a meta-ethnographic approach to analyse and synthesise the evidence. We assessed methodological limitations using a list of criteria used in previous Cochrane Reviews and originally based on the Critical Appraisal Skills Programme quality assessment tool for qualitative studies. We used the GRADE-CERQual (Confidence in the Evidence from Reviews of Qualitative research) approach to assess our confidence in each finding. We integrated the findings of this review with those from relevant Cochrane Reviews of intervention effectiveness. We did this by mapping whether the underlying theories or components of trial interventions included in those reviews related to or targeted the overarching factors influencing parental views and practices regarding routine childhood vaccination identified by this review.

MAIN RESULTS

We included 145 studies in the review and sampled 27 of these for our analysis. Six studies were conducted in Africa, seven in the Americas, four in South-East Asia, nine in Europe, and one in the Western Pacific. Studies included urban and rural settings, and high-, middle-, and low-income settings. Many complex factors were found to influence parents' vaccination views and practices, which we divided into four themes. Firstly, parents' vaccination ideas and practices may be influenced by their broader ideas and practices surrounding health and illness generally, and specifically with regards to their children, and their perceptions of the role of vaccination within this context. Secondly, many parents' vaccination ideas and practices were influenced by the vaccination ideas and practices of the people they mix with socially. At the same time, shared vaccination ideas and practices helped some parents establish social relationships, which in turn strengthened their views and practices around vaccination. Thirdly, parents' vaccination ideas and practices may be influenced by wider political issues and concerns, and particularly their trust (or distrust) in those associated with vaccination programmes. Finally, parents' vaccination ideas and practices may be influenced by their access to and experiences of vaccination services and their frontline healthcare workers. We developed two concepts for understanding possible pathways to reduced acceptance of childhood vaccination. The first concept, 'neoliberal logic', suggests that many parents, particularly from high-income countries, understood health and healthcare decisions as matters of individual risk, choice, and responsibility. Some parents experienced this understanding as in conflict with vaccination programmes, which emphasise generalised risk and population health. This perceived conflict led some parents to be less accepting of vaccination for their children. The second concept, 'social exclusion', suggests that some parents, particularly from low- and middle-income countries, were less accepting of childhood vaccination due to their experiences of social exclusion. Social exclusion may damage trustful relationships between government and the public, generate feelings of isolation and resentment, and give rise to demotivation in the face of public services that are poor quality and difficult to access. These factors in turn led some parents who were socially excluded to distrust vaccination, to refuse vaccination as a form of resistance or a way to bring about change, or to avoid vaccination due to the time, costs, and distress it creates. Many of the overarching factors our review identified as influencing parents' vaccination views and practices were underrepresented in the interventions tested in the four related Cochrane Reviews of intervention effectiveness.

AUTHORS' CONCLUSIONS

Our review has revealed that parents' views and practices regarding childhood vaccination are complex and dynamic social processes that reflect multiple webs of influence, meaning, and logic. We have provided a theorised understanding of the social processes contributing to vaccination acceptance (or not), thereby complementing but also extending more individualistic models of vaccination acceptance. Successful development of interventions to promote acceptance and uptake of childhood vaccination will require an understanding of, and then tailoring to, the specific factors influencing vaccination views and practices of the group(s) in the target setting. The themes and concepts developed through our review could serve as a basis for gaining this understanding, and subsequent development of interventions that are potentially more aligned with the norms, expectations, and concerns of target users.

Vaccine hesitancy: evidence from an adverse events following immunization database, and the role of cognitive biases

BACKGROUND

Vaccine hesitancy has been a growing challenge for public health in recent decades. Among factors contributing to vaccine hesitancy, concerns regarding vaccine safety and Adverse Events (AEs) play the leading role. Moreover, cognitive biases are critical in connecting such concerns to vaccine hesitancy behaviors, but their role has not been comprehensively studied. In this study, our first objective is to address concerns regarding vaccine AEs to increase vaccine acceptance. Our second objective is to identify the potential cognitive biases connecting vaccine hesitancy concerns to vaccine-hesitant behaviors and identify the mechanism they get triggered in the vaccine decision-making process.

METHODS

First, to mitigate concerns regarding AEs, we quantitatively analyzed the U.S. Vaccine Adverse Event Reporting System (VAERS) from 2011 to 2018 and provided evidence regarding the non-severity of the AEs that can be used as a communicable summary to increase vaccine acceptance. Second, we focused on the vaccination decision-making process. We reviewed cognitive biases and vaccine hesitancy literature to identify the most potential cognitive biases that affect vaccine hesitancy and categorized them adopting the Precaution Adoption Process Model (PAPM).

RESULTS

Our results show that the top frequent AEs are expected mild reactions like injection site erythema (4.29%), pyrexia (3.66%), and injection site swelling (3.21%). 94.5% of the reports are not serious and the average population-based serious reporting rate over the 8 years was 25.3 reports per 1 million population. We also identified 15 potential cognitive biases that might affect people's vaccination decision-making and nudge them toward vaccine hesitancy. We categorized these biases based on the factors that trigger them and discussed how they contribute to vaccine hesitancy.

CONCLUSIONS

This paper provided an evidence-based communicable summary of VAERS. As the most trusted sources of vaccine information, health practitioners can use this summary to provide evidence-based vaccine information to vaccine decision-makers (patients/parents) and mitigate concerns over vaccine safety and AEs. In addition, we identified 15 potential cognitive biases that might affect the vaccination decision-making process and nudge people toward vaccine hesitancy. Any plan, intervention, and message to increase vaccination uptake should be modified to decrease the effect of these potential cognitive biases.

Vaccine Hesitancy, Acceptance, and Anti-Vaccination: Trends and Future Prospects for Public Health

An often-stated public health comment is that "vaccination is a victim of its own success." While the scientific and medical consensus on the benefits of vaccination is clear and unambiguous, an increasing number of people are perceiving vaccines as unsafe and unnecessary. The World Health Organization identified "the reluctance or refusal to vaccinate despite availability of vaccines" as one of the 10 threats to global health in 2019. The negative influence of anti-vaccination movements is often named as a cause of increasing vaccine resistance in the public. In this review, we give an overview of the current literature on the topic, beginning by agreeing on terminology and concepts before looking at potential causes, consequences, and impacts of resistance to vaccination.

Vaccination coverage estimates and utilization patterns of inactivated enterovirus 71 vaccine post vaccine introduction in Ningbo, China

Background

In China, enterovirus 71 (EV71) is the major etiological agents of hand foot mouth disease that poses severe risks to children’s health. Since 2015, three inactivated EV71 vaccines have been approved for use. Previous studies indicated the high willingness of EV71 vaccination in eastern China. However, few studies have assessed coverage and utilization patterns of EV71 vaccine in China.

Methods

Children born during 2012–2018 were sampled and their records were abstracted from Ningbo childhood immunization information management system. Descriptive statistics characterized the study population and assessed coverage and timeliness for EV71 vaccination. Simultaneous administration patterns as well as type of EV71 vaccine used were also evaluated. Bivariate and multivariable analysis was used to examine the relationship of socio-demographic characteristics with vaccination coverage and timeliness.

Results

Of 716,178 children living in Ningbo. One hundred seventy-two thousand two hundred thirty-six received EV71 vaccine with a coverage rate of 24.05% and only 8.61% received vaccination timely. 21.97% of children received the complete two dose EV71 series but only 6.49% completed timely. Vaccination coverage and timeliness increased significantly from 2012 birth cohort to 2018 birth cohort. Relatively higher coverage and timeliness were observed in resident children, Inner districts, high socioeconomic areas and large-scaled immunization clinics. Of 329,569 doses of EV71 vaccine, only 5853(1.78%) doses were administered at the same day as other vaccines.

Conclusions

There is a need for increasing EV71 vaccination coverage and timeliness as well as eliminating disparities among different populations. Our study highlights the importance of simultaneous administration to increasing coverage and timeliness of EV71 vaccination.

Vaccination against SARS-CoV-2: a human enhancement story

BACKGROUND

Vaccination is an essential strategy for mitigating the COVID-19 pandemic. Besides its significance as a public health measure, vaccination is a sophisticated example of modern biotechnology. Since vaccination gives the human body an ability that it does not naturally possess, the question arises as to its classification as Human Enhancement.

MAIN BODY

Exemplified on a selection of different definitions, we conclude that vaccinations may indeed be classified and treated as a form of Human Enhancement. This raises some ethical issues that are notorious in the broad field of Human Enhancement. A study with N = 67 participants revealed that vaccinations are perceived neither as a clear nor poor example of Human Enhancement.

CONCLUSION

 We argue that qualifying vaccination technology as Human Enhancement does not provide convincing arguments to reject vaccination. By examining the Human Enhancement debate and the similarities to the issue of vaccination shown here, policymakers can learn valuable lessons regarding mass vaccination programs' current and future handling.

Decision making processes underlying avoidance of mandatory child vaccination in Croatia - a qualitative study

Despite extensive research evidencing child vaccination is safe and effective, we are witnessing a trend of increasing vaccine hesitancy which is listed among the top ten global health threats. Although some countries incorporate mandatory vaccination programs, no particularly efficient strategies for addressing vaccine avoidance have so far been identified. Within this study we investigated perceptions and reasoning of vaccine hesitant parents from Croatia where child vaccination is mandatory. The aims were to reveal different strategies by which they avoid mandatory vaccination schedules and hypothetical situations in which they would reconsider vaccinating, as well as to identify features of related decision-making. We conducted 25 semi-structured interviews with vaccine hesitant parents and analyzed the data using the framework of thematic analyses. The identified themes were related to the parents’ decision-making process, reflection as well as justification of their decision, avoidance behavior of mandatory vaccination schedules and related consequences, dealing with outcomes of the decision and reconsidering vaccinating. The results support and extend previous findings regarding vaccine reasoning, linking hesitancy with the experientially intuitive thinking style and social intuitionist model of moral reasoning. The findings provide important insights into vaccination avoidance and potential for reconsideration, as well as dealing with related risks. Furthermore, we offer a general framework as well as practical guidelines that may help the development of strategies aimed at increasing vaccination rates.

Clinical Practices for Measles-Mumps-Rubella Vaccination Among US Pediatric International Travelers

IMPORTANCE

The US population is experiencing a resurgence of measles, with more than 1000 cases during the first 6 months of 2019. Imported measles cases among returning international travelers are the source of most US measles outbreaks, and these importations can be reduced with pretravel measles-mumps-rubella (MMR) vaccination of pediatric travelers. Although it is estimated that children account for less than 10% of US international travelers, pediatric travelers account for 47% of all known measles importations.

OBJECTIVE

To examine clinical practice regarding MMR vaccination of pediatric international travelers and to identify reasons for nonvaccination of pediatric travelers identified as MMR eligible.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study of pediatric travelers (ages ≥6 months and <18 years) attending pretravel consultation at 29 sites associated with Global TravEpiNet (GTEN), a Centers for Disease Control and Prevention-supported consortium of clinical sites that provide pretravel consultations, was performed from January 1, 2009, through December 31, 2018.

MAIN OUTCOMES AND MEASURES

Measles-mumps-rubella vaccination among MMR vaccination-eligible pediatric travelers.

RESULTS

Of 14 602 pretravel consultations for pediatric international travelers, 2864 travelers (19.6%; 1475 [51.5%] males; 1389 [48.5%] females) were eligible to receive pretravel MMR vaccination at the time of the consultation: 365 of 398 infants aged 6 to 12 months (91.7%), 2161 of 3623 preschool-aged travelers aged 1 to 6 years (59.6%), and 338 of 10 581 school-aged travelers aged 6 to 18 years (3.2%). Of 2864 total MMR vaccination-eligible travelers, 1182 (41.3%) received the MMR vaccine and 1682 (58.7%) did not. The MMR vaccination-eligible travelers who did not receive vaccine included 161 of 365 infants (44.1%), 1222 of 2161 preschool-aged travelers (56.5%), and 299 of 338 school-aged travelers (88.5%). We observed a diversity of clinical practice at different GTEN sites. In multivariable analysis, MMR vaccination-eligible pediatric travelers were less likely to be vaccinated at the pretravel consultation if they were school-aged (model 1: odds ratio [OR], 0.32 [95% CI, 0.24-0.42; P < .001]; model 2: OR, 0.26 [95% CI, 0.14-0.47; P < .001]) or evaluated at specific GTEN sites (South: OR, 0.06 [95% CI, 0.01-0.52; P < .001]; West: OR, 0.10 [95% CI, 0.02-0.47; P < .001]). The most common reasons for nonvaccination were clinician decision not to administer MMR vaccine (621 of 1682 travelers [36.9%]) and guardian refusal (612 [36.4%]).

CONCLUSIONS AND RELEVANCE

Although most infant and preschool-aged travelers evaluated at GTEN sites were eligible for pretravel MMR vaccination, only 41.3% were vaccinated during pretravel consultation, mostly because of clinician decision or guardian refusal. Strategies may be needed to improve MMR vaccination among pediatric travelers and to reduce measles importations and outbreaks in the United States.

A meta-synthesis study of the key elements involved in childhood vaccine hesitancy

OBJECTIVES

Immunization is one of the most successful and cost-effective interventions to improve health outcomes. However, internationally, the phenomenon of parental vaccine hesitancy is increasing and presents a growing challenge for health professionals. This article summarizes the evidence surrounding childhood vaccine hesitancy from the perspective of parents.

STUDY DESIGN

We conducted a systematic review and meta-synthesis of qualitative studies.

METHODS

We searched for qualitative research articles in electronic databases from inception to March 2018. In addition, a manual search of the retrieved articles and their references was conducted to identify other potential articles. We used the Critical Appraisal Skills Programme to examine study validity, adequacy and potential applicability of the results. No articles were excluded for reasons of quality. By performing a meta-synthesis, we identified descriptive themes and, subsequently, the conceptual elements of vaccine hesitancy.

RESULTS

The review included 27 studies involving a total of 1557 parents who were hesitant about vaccinating their child. Five overarching categories were identified: (1) risk conceptualization; (2) mistrust towards vaccine-related institutions, pharmaceutical companies, researchers, health professionals and the information from media; (3) parental alternative health beliefs about childhood immunity, vaccine scheduling and the perceived toxicity of vaccinations; (4) philosophical views on parental responsibility; and (5) parents' information levels about vaccination.

CONCLUSIONS

Healthcare providers need to approach this difficult situation considering that parents desire to do what they feel right for the child. Understanding the core elements of hesitancy will allow health professionals to adopt effective communication and behavioural strategies.

It just doesn't feel right - the relevance of emotions and intuition for parental vaccine conspiracy beliefs and vaccination uptake

Objective: Vaccine hesitancy has been identified as one of the major contributors to child under-vaccination. Research indicates that some hesitant parents' mistrust extends to specific conspiracy ideation, but research on vaccine conspiracy beliefs is still scarce. Our objective was to explore factors contributing to parental vaccine conspiracy beliefs and actual vaccine uptake in children.Design: A cross-sectional correlational design with a non-probabilistic sample of 823 volunteer participants surveyed online.Main outcome measures: We focussed on the contributions of the analytically rational and experientially intuitive thinking styles, as well as measures of emotional functioning, namely optimism and emotions towards vaccination, to vaccine conspiracy beliefs and vaccine uptake as outcomes.Results: The obtained results showed that greater vaccine conspiracy beliefs were associated with stronger unpleasant emotions towards vaccination and greater experientially intuitive thinking, as well as lower levels of education. Furthermore, unpleasant emotions towards vaccination and intuitive thinking were associated with vaccine refusal.Conclusion: These findings confirm the primary importance of emotions, along with the propensity towards intuitive thinking, in the context of vaccine conspiracy beliefs and refusal, supporting the notion that parents' avoidance is guided by their affect. These results have direct implications for addressing vaccine hesitancy within public campaigns and policies.

Beliefs around childhood vaccines in the United States: A systematic review

BACKGROUND

While childhood vaccines are safe and effective, some parents remain hesitant to vaccinate their children, which has led to outbreaks of vaccine preventable diseases. The goal of this systematic review was to identify and summarize the range of beliefs around childhood vaccines elicited using open-ended questions, which are better suited for discovering beliefs compared to closed-ended questions.

METHODS

PubMed, Embase, and PsycINFO were searched using keywords for childhood vaccines, decision makers, beliefs, and attitudes to identify studies that collected primary data using a variety of open-ended questions regarding routine childhood vaccine beliefs in the United States. Study designs, population characteristics, vaccine types, and vaccine beliefs were abstracted. We conducted a qualitative analysis to conceptualize beliefs into themes and generated descriptive statistics.

RESULTS

Of 1727 studies identified, 71 were included, focusing largely on parents (including in general, and those who were vaccine hesitant or at risk of hesitancy). Seven themes emerged: Adverse effects was most prominent, followed by mistrust, perceived lack of necessity, pro-vaccine opinions, skepticism about effectiveness, desire for autonomy, and morality concerns. The most commonly described beliefs included that vaccines can cause illnesses; a child's immune system can be overwhelmed if receiving too many vaccines at once; vaccines contain harmful ingredients; younger children are more susceptible to vaccine adverse events; the purpose of vaccines is profit-making; and naturally developed immunity is better than that acquired from vaccines. Nearly a third of the studies exclusively assessed minority populations, and more than half of the studies examined beliefs only regarding HPV vaccine.

CONCLUSIONS

Few studies used open-ended questions to elicit beliefs about vaccines. Many of the studies that did so, focused on HPV vaccine. Concerns about vaccine safety were the most commonly stated beliefs about childhood vaccines, likely because studies were designed to capture barriers and challenges to vaccination.

Nudge or Grudge? Choice Architecture and Parental Decision-Making

Richard Thaler and Cass Sunstein define a nudge as "any aspect of the choice architecture that alters people's behavior in a predictable way without forbidding any options or significantly changing their economic incentives." Much has been written about the ethics of nudging competent adult patients. Less has been written about the ethics of nudging surrogates' decision-making and how the ethical considerations and arguments in that context might differ. Even less has been written about nudging surrogate decision-making in the context of pediatrics, despite fundamental differences that exist between the pediatric and adult contexts. Yet, as the field of behavioral economics matures and its insights become more established and well-known, nudges will become more crafted, sophisticated, intentional, and targeted. Thus, the time is now for reflection and ethical analysis regarding the appropriateness of nudges in pediatrics. We argue that there is an even stronger ethical justification for nudging in parental decision-making than with competent adult patients deciding for themselves. We give three main reasons in support of this: (1) child patients do not have autonomy that can be violated (a concern with some nudges), and nudging need not violate parental decision-making authority; (2) nudging can help fulfill pediatric clinicians' obligations to ensure parental decisions are in the child's interests, particularly in contexts where there is high certainty that a recommended intervention is low risk and of high benefit; and (3) nudging can relieve parents' decisional burden regarding what is best for their child, particularly with decisions that have implications for public health.

Communication of Scientific Uncertainty about a Novel Pandemic Health Threat: Ambiguity Aversion and Its Mechanisms

Communicating scientific uncertainty about public health threats is ethically desirable but challenging due to its tendency to promote avoidance of choice options with unknown probabilities-a phenomenon known as "ambiguity aversion." This study examined this phenomenon's potential magnitude, its responses to different communication strategies, and its mechanisms. In a factorial experiment, 2701 adult laypersons in Spain read one of three versions of a hypothetical newspaper article describing a pandemic vaccine-preventable disease (VPD), but varying in scientific uncertainty about VPD risk and vaccine effectiveness: No-Uncertainty, Uncertainty, and Normalized-Uncertainty (emphasizing its expected nature). Vaccination intentions were lower for the Uncertainty and Normalized-Uncertainty groups compared to the No-Uncertainty group, consistent with ambiguity aversion; Uncertainty and Normalized-Uncertainty groups did not differ. Ambiguity-averse responses were moderated by health literacy and mediated by perceptions of vaccine effectiveness, VPD likelihood, and VPD severity. Communicating scientific uncertainty about public health threats warrants caution and further research to elucidate its outcomes, mechanisms, and management.

Understanding the Cognitive and Affective Mechanisms that Underlie Proxy Risk Perceptions among Caregivers of Asthmatic Children

OBJECTIVE

Medical decisions made on behalf of another person-particularly those made by adult caregivers for their minor children-are often informed by the decision maker's beliefs about the treatment's risks and benefits. However, we know little about the cognitive and affective mechanisms influencing such "proxy" risk perceptions and about how proxy risk perceptions are related to prominent judgment phenomena.

METHODS

Adult caregivers of minor children with asthma ( N = 132) completed an online, cross-sectional survey assessing 1) cognitions and affects that form the basis of the availability, representativeness, and affect heuristics; 2) endorsement of the absent-exempt and the better-than-average effect; and 3) proxy perceived risk and unrealistic comparative optimism of an asthma exacerbation. We used the Pediatric Asthma Control and Communication Instrument (PACCI) to assess asthma severity.

RESULTS

Respondents with higher scores on availability, representativeness, and negative affect indicated higher proxy risk perceptions and (for representativeness only) lower unrealistic optimism, irrespective of asthma severity. Conversely, respondents who showed a stronger display of the better-than-average effect indicated lower proxy risk perceptions but did not differ in unrealistic optimism. The absent-exempt effect was unrelated to proxy risk perceptions and unrealistic optimism.

CONCLUSION

Heuristic judgment processes appear to contribute to caregivers' proxy risk perceptions of their child's asthma exacerbation risk. Moreover, the display of other, possibly erroneous, judgment phenomena is associated with lower caregiver risk perceptions. Designing interventions that target these mechanisms may help caregivers work with their children to reduce exacerbation risk.

Missed Opportunities for Measles, Mumps, Rubella Vaccination Among Departing U.S. Adult Travelers Receiving Pretravel Health Consultations

Background

Measles outbreaks continue to occur in the United States and are mostly due to infections in returning travelers.

Objective

To describe how providers assessed the measles immunity status of departing U.S. adult travelers seeking pretravel consultation and to assess reasons given for nonvaccination among those considered eligible to receive the measles, mumps, rubella (MMR) vaccine.

Design

Observational study in U.S. pretravel clinics.

Setting

24 sites associated with Global TravEpiNet (GTEN), a Centers for Disease Control and Prevention-funded consortium.

Patients

Adults (born in or after 1957) attending pretravel consultations at GTEN sites (2009 to 2014).

Measurements

Structured questionnaire completed by traveler and provider during pretravel consultation.

Results

40 810 adult travelers were included; providers considered 6612 (16%) to be eligible for MMR vaccine at the time of pretravel consultation. Of the MMR-eligible, 3477 (53%) were not vaccinated at the visit; of these, 1689 (48%) were not vaccinated because of traveler refusal, 966 (28%) because of provider decision, and 822 (24%) because of health systems barriers. Most MMR-eligible travelers who were not vaccinated were evaluated in the South (2262 travelers [65%]) or at nonacademic centers (1777 travelers [51%]). Nonvaccination due to traveler refusal was most frequent in the South (1432 travelers [63%]) and in nonacademic centers (1178 travelers [66%]).

Limitation

These estimates could underrepresent the opportunities for MMR vaccination because providers accepted verbal histories of disease and vaccination as evidence of immunity.

Conclusion

Of U.S. adult travelers who presented for pretravel consultation at GTEN sites, 16% met criteria for MMR vaccination according to the provider's assessment, but fewer than half of these travelers were vaccinated. An increase in MMR vaccination of eligible U.S. adult travelers could reduce the likelihood of importation and transmission of measles virus.

Primary Funding Source

Centers for Disease Control and Prevention, National Institutes of Health, and the Steve and Deborah Gorlin MGH Research Scholars Award.

Parents' and informal caregivers' views and experiences of communication about routine childhood vaccination: a synthesis of qualitative evidence

BACKGROUND

Childhood vaccination is an effective way to prevent serious childhood illnesses, but many children do not receive all the recommended vaccines. There are various reasons for this; some parents lack access because of poor quality health services, long distances or lack of money. Other parents may not trust vaccines or the healthcare workers who provide them, or they may not see the need for vaccination due to a lack of information or misinformation about how vaccinations work and the diseases they can prevent.Communication with parents about childhood vaccinations is one way of addressing these issues. Communication can take place at healthcare facilities, at home or in the community. Communication can be two-way, for example face-to-face discussions between parents and healthcare providers, or one-way, for instance via text messages, posters or radio programmes. Some types of communication enable parents to actively discuss vaccines and their benefits and harms, as well as diseases they can prevent. Other communication types simply give information about vaccination issues or when and where vaccines are available. People involved in vaccine programmes need to understand how parents experience different types of communication about vaccination and how this influences their decision to vaccinate.

OBJECTIVES

The specific objectives of the review were to identify, appraise and synthesise qualitative studies exploring: parents' and informal caregivers' views and experiences regarding communication about childhood vaccinations and the manner in which it is communicated; and the influence that vaccination communication has on parents' and informal caregivers' decisions regarding childhood vaccination.

SEARCH METHODS

We searched MEDLINE (OvidSP), MEDLINE In-process and Other Non-Index Citations (Ovid SP), Embase (Ovid), CINAHL (EbscoHOST), and Anthropology Plus (EbscoHost) databases for eligible studies from inception to 30 August 2016. We developed search strategies for each database, using guidelines developed by the Cochrane Qualitative Research Methods Group for searching for qualitative evidence as well as modified versions of the search developed for three related reviews of effectiveness. There were no date or geographic restrictions for the search.

SELECTION CRITERIA

We included studies that utilised qualitative methods for data collection and analysis; focused on the views and experiences of parents and informal caregivers regarding information about vaccination for children aged up to six years; and were from any setting globally where information about childhood vaccinations was communicated or distributed.

DATA COLLECTION AND ANALYSIS

We used maximum variation purposive sampling for data synthesis, using a three-step sampling frame. We conducted a thematic analysis using a constant comparison strategy for data extraction and synthesis. We assessed our confidence in the findings using the GRADE-CERQual approach. High confidence suggests that it is highly likely that the review finding is a reasonable representation of the phenomenon of interest, while very low confidence indicates that it is not clear whether the review finding is a reasonable representation of it. Using a matrix model, we then integrated our findings with those from other Cochrane reviews that assessed the effects of different communication strategies on parents' knowledge, attitudes and behaviour about childhood vaccination.

MAIN RESULTS

We included 38 studies, mostly from high-income countries, many of which explored mothers' perceptions of vaccine communication. Some focused on the MMR (measles, mumps, rubella) vaccine.In general, parents wanted more information than they were getting (high confidence in the evidence). Lack of information led to worry and regret about vaccination decisions among some parents (moderate confidence).Parents wanted balanced information about vaccination benefits and harms (high confidence), presented clearly and simply (moderate confidence) and tailored to their situation (low confidence in the evidence). Parents wanted vaccination information to be available at a wider variety of locations, including outside health services (low confidence) and in good time before each vaccination appointment (moderate confidence).Parents viewed health workers as an important source of information and had specific expectations of their interactions with them (high confidence). Poor communication and negative relationships with health workers sometimes impacted on vaccination decisions (moderate confidence).Parents generally found it difficult to know which vaccination information source to trust and challenging to find information they felt was unbiased and balanced (high confidence).The amount of information parents wanted and the sources they felt could be trusted appeared to be linked to acceptance of vaccination, with parents who were more hesitant wanting more information (low to moderate confidence).Our synthesis and comparison of the qualitative evidence shows that most of the trial interventions addressed at least one or two key aspects of communication, including the provision of information prior to the vaccination appointment and tailoring information to parents' needs. None of the interventions appeared to respond to negative media stories or address parental perceptions of health worker motives.

AUTHORS' CONCLUSIONS

We have high or moderate confidence in the evidence contributing to several review findings. Further research, especially in rural and low- to middle-income country settings, could strengthen evidence for the findings where we had low or very low confidence. Planners should consider the timing for making vaccination information available to parents, the settings where information is available, the provision of impartial and clear information tailored to parental needs, and parents' perceptions of health workers and the information provided.

Food Labeling and Consumer Associations with Health, Safety, and Environment

The food supply is complicated and consumers are increasingly calling for labeling on food to be more informative. In particular, consumers are asking for the labeling of food derived from genetically modified organisms (GMO) based on health, safety, and environmental concerns. At issue is whether the labels that are sought would accurately provide the information desired. The present study examined consumer (n = 181) perceptions of health, safety and the environment for foods labeled organic, natural, fat free or low fat, GMO, or non-GMO. Findings indicated that respondents consistently believed that foods labeled GMO are less healthy, safe and environmentally-friendly compared to all other labels (ps < .05). These results suggest that labels mean something to consumers, but that a disconnect may exist between the meaning associated with the label and the scientific consensus for GMO food. These findings may provide insight for the development of labels that provide information that consumers seek.

Attitudes and Beliefs of Pregnant Women and New Mothers Regarding Influenza Vaccination in British Columbia

OBJECTIVE

Although pregnant women have increased risks for influenza morbidity and mortality, influenza vaccination rates among pregnant women in Canada are consistently very low. This mixed-methods study investigated the attitudes and behaviour of pregnant women and new mothers regarding seasonal and pandemic influenza vaccination.

METHODS

We conducted a baseline survey and qualitative focus groups with 34 women (26 pregnant women and 8 mothers of newborns), with a follow-up survey to assess outcomes at the end of the subsequent influenza season. Data analysis included descriptive statistics and directed content analysis based on the health belief model.

RESULTS

Most women did not consider influenza vaccination to be an important preventative measure to take while pregnant, although some were more willing to consider vaccination during a pandemic. Omission bias played a substantial role as justification for not vaccinating. Participants expressed confusion about recommendations regarding vaccination during pregnancy and frustration with inconsistent messages from health care providers (HCPs), particularly with regard to pandemic vaccines. Women were vaccinated when they perceived themselves and/or their babies to be at increased risk for influenza. Vaccinated women had strong normative influences (usually an HCP or a family member) that affected their decision. Intentions accurately predicted behaviour for women who did and did not intend to be vaccinated.

CONCLUSION

Pregnant women did not perceive themselves to be at increased risk for influenza and did not believe that influenza vaccination was a necessary preventative health measure. A lack of safety information about vaccination during pregnancy and inconsistent messages from HCPs were barriers to vaccine acceptance. Recommendations from maternity care providers and communication about the severity of and susceptibility to influenza for pregnant women would facilitate vaccine uptake.

"You need to be an advocate for yourself": Factors associated with decision-making regarding influenza and pneumococcal vaccine use among US older adults from within a large metropolitan health system

In the United States, influenza and pneumonia account significantly to emergency room use and hospitalization of adults >65 y. The Centers for Disease Control and Prevention recommends use of the annual influenza vaccine and 2 pneumococcal vaccines for older adults to decrease risks of morbidity and mortality. However, actual vaccine up-take is estimated at 61.3% for pneumococcal vaccines and 65% for influenza vaccine in the 2013-2014 season. Vaccine up-take is affected by multiple socio-cultural and economic factors including general healthcare access and utilization, social networks and norms, communication with health providers and health information sources, as well as perceptions related to vaccines and targeted diseases. In this study, 8 focus group discussions (total N = 48) were conducted with adults 65+ years living in urban and suburban communities in the Detroit Metropolitan Area. The research objective was to increase understanding of barriers and facilitators to vaccine up-take in this age cohort within the context of general healthcare availability and accessibility, social networks, information sources, and personal perceptions of diseases and vaccines. The data suggest the need to integrate broader health care service experiences, concepts of knowledge of one's own well-being and vulnerabilities, and self-advocacy as factors associated with older adults' vaccine-use decisions. These data also support recognition of multiple levels of vaccine acceptance which can be disease specific. Implications include potential for increasing vaccine up-take through general improvement in health care delivery and services, as well as specific vaccine-focused patient and provider education programs.

The Challenges in Measuring Local Immunization Coverage: A Statewide Case Study

There are many forms of existing immunization surveillance in the United States and Washington state, but all are limited in their ability to provide timely identification of clusters of unimmunized individuals and assess the risk of vaccine-preventable diseases. This article aims to: (1) describe challenges to measuring immunization coverage at a local level in the United States using Washington State as a case study; and (2) propose improvements to existing surveillance systems that address the challenges identified.

Can the vaccine adverse event reporting system be used to increase vaccine acceptance and trust?

Vaccine refusal has an impact on public health, and the human pappillomavirus (HPV) vaccine is particularly underutilized. Research suggests that it may be difficult to change vaccine-related attitudes, and there is currently no good evidence to recommend any particular intervention strategy. One reason for vaccine hesitancy is lack of trust that vaccine harms are adequately documented and reported, yet few communication strategies have explicitly attempted to improve this trust. This study tested the possibility that data from the vaccine adverse event reporting system (VAERS) can be used to increase trust that vaccine harms are adequately researched and that potential harms are disclosed to the public, and thereby improve perceptions of vaccines. In the study, participants were randomly assigned to one of three communication interventions. All participants read the Centers for Disease Control (CDC) vaccine information statement (VIS) for the HPV vaccine. Two other groups were exposed to additional information about VAERS, either summary data or full detailed reports of serious adverse events from 2013. Results showed that the CDC's VIS alone significantly increased perceptions of vaccine benefits and decreased perceived risks. Participants who were also educated about VAERS and given summary data about the serious adverse events displayed more trust in the CDC and greater HPV vaccine acceptance relative to the VIS alone. However, exposure to the detailed VAERS reports significantly reduced trust in the CDC and vaccine acceptance. Hence, general information about the VAERS data slightly increased trust in the CDC and improved vaccine acceptance, but the specific VAERS reports negatively influenced both trust and acceptance. Implications for communicating about vaccines are discussed.