Interventions to help people understand community immunity: A systematic review

Collective antiretroviral protection: new dimensions of community HIV prevention practices at the intersection of U=U and PrEP

Collective antiretroviral protection is an evolving sexual health strategy in HIV prevention, used in particular by gay, bisexual, and other men who have sex with men. The strategy involves HIV-negative individuals who engage in condomless sexual activities but, instead of using pre-exposure prophylaxis (PrEP) themselves, choose partners who either have undetectable viral loads or are on PrEP. This biomedical-sorting practice, rooted in the scientific principles of undetectable equals untransmittable (U=U) and PrEP, relies on an indirect protection strategy. Collective antiretroviral protection allows for HIV-negative individuals not on PrEP to benefit from their partner's antiretroviral use, without directly consuming antiretrovirals themselves for HIV prevention, during condomless sex. Empirical research is needed to evaluate the public health implications of this emerging sexual health approach. Research and public health initiatives should adopt a non-stigmatising approach to individuals engaging in collective antiretroviral protection and look beyond individual behaviour to understand the broader community-level effects of this innovative HIV prevention strategy.

Moral obligation, autonomous motivation and vaccine hesitancy: Highlighting moral obligation increases reactance in hesitant individuals

Vaccine hesitancy is widespread, and developing effective communication strategies that encourage hesitant individuals to choose vaccination is essential. This pre-registered research aimed to examine associations among moral obligation, autonomous motivation, vaccination intentions and reactance, and to test messages highlighting moral obligation and autonomy support. In Study 1, participants who had not received a Covid-19 vaccine (N = 1036) completed measures of autonomous motivation, moral obligation, reactance, intentions to vaccinate and vaccine hesitancy. Autonomous motivation and moral obligation emerged as strong independent predictors of lower reactance, lower hesitancy and greater vaccination intentions. In Study 2 (N = 429), the participants received a vaccination-promoting message that highlighted moral obligation versus personal protection and used autonomy supportive versus controlling language. Messages with autonomy-supportive language and highlighting personal protection elicited lower reactance and greater perceived legitimacy compared to messages with controlling language and highlighting moral obligation. All messages elicited greater reactance and lower perceived legitimacy compared to an information-only message, and there were no effects of message type on vaccination intentions or vaccine hesitancy. The research has implications for the design of communications encouraging vaccination in hesitant individuals and suggests caution should be taken when developing messages to encourage vaccination in hesitant individuals.

Overview of childhood vaccination coverage in Brazil and the impact of the COVID-19 pandemic: Is our children's health at risk? A review of pre-COVID-19 periods and during the COVID-19 pandemic

Introduction

The coronavirus disease (COVID)-19 has had a great impact on several aspects related to the population's health, including the vaccination adherence rate. This study describes how childhood vaccination coverage (CVC) in Brazil was affected by the pandemic in the period from 2020 to 2022 and explores the relationship between this data and the Human Development Index (HDI), and the number of votes received in the government with a right-wing political ideology.

Methods

An ecological analysis of CVC was carried out including 12 vaccines. The HDI was evaluated considering the HDI-General, HDI-Income, HDI-Longevity, and HDI-Education. The percentage of valid votes received by the former president (right-wing political ideology) was also obtained. Spearman correlation tests were applied to compare markers.

Results

During the period analyzed, it was observed a linear growth trend in CVC between 2015 and 2018 regarding all vaccines. However, from 2018 onwards, after the presidential elections in Brazil, the CVC reduced significantly, showing an even more pronounced decrease with the start of the COVID-19 pandemic. This reduction in CVC observed for some vaccines was related to the higher percentage of votes for the government with a right-wing political ideology, especially in relation to the BCG (bacillus Calmette and Guerin) and pentavalent (protecting against diphtheria, tetanus, pertussis, hepatitis B, and Haemophilus influenzae type b bacteria) vaccines. In addition, when analyzing the HDI, it was observed that the lowest values of this indicator were associated with a more expressive reduction in CVC, mainly related to yellow fever, pentavalent, 10-valent pneumococcal conjugate, Human rotavirus, and triple viral (protecting against measles, mumps, and rubella - MMR) vaccines.

Conclusion

Although Brazil has a successful and exemplary record in combating several diseases, mainly due to the high rate of CVC, the continuous reduction in this coverage must be thoroughly evaluated by health managers.

Long-Term Field Application of a Plant Growth-Promoting Rhizobacterial Consortium Suppressed Root-Knot Disease by Shaping the Rhizosphere Microbiota

Root-knot nematodes (Meloidogyne spp.) are one of the most economically important plant parasitic nematodes, infecting almost all cultivated plants and resulting in severe yield losses every year. Plant growth-promoting rhizobacteria (PGPR) have been extensively used to prevent and control root-knot diseases and increase yield. In this study, the effect of a consortium of three PGPR strains (Bacillus cereus AR156, B. subtilis SM21, and Serratia sp. XY21; hereafter "BBS") on root-knot disease of cucumber was evaluated. The application of BBS significantly reduced the severity of root-knot disease by 56 to 72%, increased yield by 36 to 55%, and improved fruit quality by 14 to 90% and soil properties by 1 to 90% relative to the control in the cucumber fields of the Nanjing suburb, Jiangsu Province, from 2015 to 2018. BBS altered the rhizosphere bacterial community. Compared with the control group, it significantly (false discovery rate, P < 0.05) increased the abundance of 14 bacterial genera that were negatively correlated with disease severity. Additionally, the redundancy analysis suggested that BBS-treated rhizosphere soil samples were dominated by disease-suppressive bacteria, including the genera Iamia, Kutzneria, Salinibacterium, Mycobacterium, Kribbella, Pseudonocardia, Sporichthya, Sphaerisporangium, Actinomadura, Flavisolibacter, Phenylobacterium, Bosea, Hyphomicrobium, Agrobacterium, Sphingomonas, and Nannocystis, which were positively related to total organic carbon, total nitrogen, total organic matter, dissolved organic carbon, [Formula: see text]-N, and available phosphorus contents. This suggests that BBS suppresses root-knot nematodes and improves the soil chemical properties of cucumber by altering the rhizosphere microbial community.

To vaccinate or not to vaccinate? The interplay between pro- and against- vaccination reasons

BACKGROUND

By mid 2023, European countries reached 75% of vaccine coverage for COVID-19 and although vaccination rates are quite high, many people are still hesitant. A plethora of studies have investigated factors associated with COVID-19 vaccine hesitancy, however, insufficient attention has been paid to the reasons why people get vaccinated against COVID-19. Our work aims to investigate the role of reasons in the decision to get vaccinated against COVID-19 in a representative sample of 1,689 adult Italians (March-April 2021) balanced in terms of age, gender, educational level and area of residence.

METHODS

Through an online questionnaire, we asked participants to freely report up to three reasons for and against COVID-19 vaccination, and the weight each had in the decision to get vaccinated. We first investigated the role of emotional competence and COVID-19 risk perception in the generation of both reasons using regression models. Next, we studied the role that the different reasons had in the vaccination decision, considering both the intention to vaccinate (using a beta regression model) and the decision made by the participants who already had the opportunity to get vaccinated (using a logistic regression model). Finally, two different classification tree analyses were carried out to characterize profiles with a low or high willingness to get vaccinated or with a low or high probability to accept/book the vaccine.

RESULTS

High emotional competence positively influences the generation of both reasons (ORs > 1.5), whereas high risk perception increases the generation of positive reasons (ORs > 1.4) while decreasing reasons against vaccination (OR = 0.64). As pro-reasons increase, vaccination acceptance increases, while the opposite happens as against-reasons increase (all p < 0.001). One strong reason in favor of vaccines is enough to unbalance the decision toward acceptance of vaccination, even when reasons against it are also present (p < 0.001). Protection and absence of distrust are the reasons that mostly drive willingness to be vaccinated and acceptance of an offered vaccine.

CONCLUSIONS

Knowing the reasons that drive people's decision about such an important choice can suggest new communication insights to reduce possible negative reactions toward vaccination and people's hesitancy. Results are discussed considering results of other national and international studies.

Experiencing herd immunity in virtual reality increases COVID-19 vaccination intention: Evidence from a large-scale field intervention study

This study investigates the impact of an immersive virtual reality (VR) simulation of herd immunity on vaccination intentions and its potential underlying mechanisms. In this preregistered field study, N = 654 participants were randomly assigned to one of the three VR conditions: (1) Gamified Herd Immunity; (2) Gamified Herd Immunity + Empathy (with additional narrative elements); (3) Control (gamified with no vaccination-related content). In the Gamified Herd Immunity simulation, participants embodied a vulnerable person and navigated a wedding venue trying to avoid getting infected. A total of 455 participants with below maximum intentions to take a novel vaccine and without severe cybersickness were analyzed. The Gamified Herd Immunity + Empathy and the Gamified Herd Immunity conditions increased vaccination intentions by 6.68 and 7.06 points on a 0-100 scale, respectively, compared to 1.91 for the Control condition. The Gamified Herd Immunity + Empathy condition enhanced empathy significantly more than the Gamified Herd Immunity condition but did not result in higher vaccination intentions. Experienced presence was related to the change in vaccination intentions. The results suggest that VR vaccination communication can effectively increase vaccination intentions; the effect is not solely due to the technological novelty and does not depend on empathy.

Pilot study to determine effect of an altruism intervention focusing on herd immunity to enhance influenza vaccination rates

OBJECTIVE

A prospective, single-arm clinical trial was conducted to evaluate an altruism-tailored educational intervention to improve parental attitudes and vaccine uptake in vaccine-hesitant parents.

METHODS

Vaccine-hesitant parents at two primary care sites, spanning two influenza seasons from 2020 to 2021 were provided an intervention (spoken and written communication) which highlighted altruistic benefits of accepting the seasonal influenza vaccine to optimize herd immunity to help protect pediatric cancer patients. Eligible parents included those with children eligible for the seasonal influenza vaccine, those who were proficient in English, and those with scores on the adjusted Vaccine Hesitancy Scale (aVHS) suggesting vaccine hesitancy (score ≥ 3). Enrollees completed a demographic questionnaire, underwent the educational intervention, and repeated the aVHS. Vaccination status at that visit was assessed. The primary outcome was change in aVHS scores obtained pre- and post-intervention. Influenza vaccine acceptance, along with demographic information, were also analyzed.

RESULTS

We enrolled 510 parents of influenza vaccine eligible children and identified 73 vaccine-hesitant parents. There was an overall trend toward lower aVHS score, with a mean change in hesitancy score of -0.4 (P < 0.01). 43/73 (58.9 %) of the cohort experienced a positive effect toward a lower aVHS score, and 27/73 (37.0 %) of vaccine hesitant subjects became non-hesitant on the aVHS. Several demographic characteristics were associated with vaccine hesitancy in the screening population: educational level lower than bachelor's degree (p = 0.03), household income < 400 % of federal poverty level (p < 0.01), unmarried (p = 0.02), and identifying with a political affiliation other than Democrat (p < 0.01). However, no demographic characteristics were significantly associated with an individual becoming non-hesitant. Our altruism-tailored communication approach carried the largest positive impact on the altruism-specific question on the aVHS, decreasing the post-intervention response value by nearly 25 % (P < 0.01).

CONCLUSIONS

Our altruism-tailored communication approach significantly improved attitudes regarding childhood influenza vaccine among vaccine-hesitant parents.

CLINICALTRIALS

gov Identifier: NCT04568590.

The effect of herd immunity thresholds on willingness to vaccinate

Throughout the COVID-19 pandemic, media and policymakers openly speculated about the number of immune citizens needed to reach a herd immunity threshold. What are the effects of such numerical goals on the willingness to vaccinate? In a large representative sample (N = 1540) of unvaccinated Swedish citizens, we find that giving a low (60%) compared to a high (90%) threshold has direct effects on beliefs about reaching herd immunity and beliefs about how many others that will get vaccinated. Presenting the high threshold makes people believe that herd immunity is harder to reach (on average about half a step on a seven-point scale), compared to the low threshold. Yet at the same time, people also believe that a higher number of the population will get vaccinated (on average about 3.3% more of the population). Since these beliefs affect willingness to vaccinate in opposite directions, some individuals are encouraged and others discouraged depending on the threshold presented. Specifically, in mediation analysis, the high threshold indirectly increases vaccination willingness through the belief that many others will get vaccinated (B = 0.027, p = 0.003). At the same time, the high threshold also decreases vaccination willingness through the belief that the threshold goal is less attainable (B = -0.053, p < 0.001) compared to the low threshold condition. This has consequences for ongoing COVID-19 vaccination and future vaccination campaigns. One message may not fit all, as different groups can be encouraged or discouraged from vaccination.

Level of Acceptance of Mandatory Vaccination and Legal Sanctions for Refusing Mandatory Vaccination of Children

A preventive vaccination program is in operation in Poland. There are mandatory vaccinations for Polish residents under the age of 19 years. The law provides for financial penalties for parents who refuse to vaccinate their children. The aim of this study was to describe the attitudes of Polish residents aged 15–39 years to mandatory preventive vaccination and the level of acceptance for legal and financial sanctions for refusing mandatory vaccination of children. Materials and Methods: A face-to-face questionnaire-based study of a representative sample of 1560 residents of Poland aged 15–39 years. Data was collected in the fourth quarter of 2021. Results: In the study group, 51.5% of the respondents believed that preventive vaccination should be mandatory, and parents should have the right to decide only about additional vaccinations. Multivariate analyses (logistic regression) revealed a significant association between acceptance of mandatory vaccination and the following factors: positive COVID-19 vaccination status, self-declared religiosity, and having children. Of the 1560 respondents, 25.3% declared support for legal or financial sanctions for those refusing to vaccinate their children. In this group (n = 394), the highest percentage of respondents (59.4%) supported sanctions in the form of refusal to admit an unvaccinated child to a nursery or kindergarten. Conclusions: Despite preventive (mandatory) vaccination programs having been in operation in Poland since the 1960′s, only a little over 50% of adolescent Poles and young adults accept the vaccine mandate. Only 25% of this group declare their support for sanctions for refusing mandatory vaccination of children.

Keeping the Kids Home

Abstract. During the COVID-19 pandemic, social consequences in day-to-day decisions might not have been salient to the decider and thus egoistic. How can prosocial intentions be increased? In an experimental vignette study with N = 206, we compared the likelihood that parents send sick children to kindergarten after four interventions (general information about COVID-19, empathy, reflection of consequences via mental simulation, and control group). Independent of the intervention, empathic concern with individuals who were affected by COVID-19 and the salience of social consequences were high. The reported likelihood of sending a sick child to kindergarten was somewhat reduced in the control group and even more reduced in the reflection and empathy group, but not in the information group.

Virtual reality reduces COVID-19 vaccine hesitancy in the wild: a randomized trial

Vaccine hesitancy poses one of the largest threats to global health. Informing people about the collective benefit of vaccination has great potential in increasing vaccination intentions. This research investigates the potential for engaging experiences in immersive virtual reality (VR) to strengthen participants' understanding of community immunity, and therefore, their intention to get vaccinated. In a pre-registered lab-in-the-field intervention study, participants were recruited in a public park (tested: [Formula: see text], analyzed: [Formula: see text]). They were randomly assigned to experience the collective benefit of community immunity in a gamified immersive virtual reality environment ([Formula: see text] of sample), or to receive the same information via text and images ([Formula: see text] of sample). Before and after the intervention, participants indicated their intention to take up a hypothetical vaccine for a new COVID-19 strain (0-100 scale) and belief in vaccination as a collective responsibility (1-7 scale). The study employs a crossover design (participants later received a second treatment), but the primary outcome is the effect of the first treatment on vaccination intention. After the VR treatment, for participants with less-than-maximal vaccination intention, intention increases by 9.3 points (95% CI: 7.0 to [Formula: see text]). The text-and-image treatment raises vaccination intention by 3.3 points (difference in effects: 5.8, 95% CI: 2.0 to [Formula: see text]). The VR treatment also increases collective responsibility by 0.82 points (95% CI: 0.37 to [Formula: see text]). The results suggest that VR interventions are an effective tool for boosting vaccination intention, and that they can be applied "in the wild"-providing a complementary method for vaccine advocacy.

Qualitative exploration of intentions, concerns and information needs of vaccine-hesitant adults initially prioritised to receive COVID-19 vaccines in Australia

OBJECTIVE

Tailored communication is necessary to address COVID-19 vaccine hesitancy and increase uptake. We aimed to understand the information needs, perceived benefits and barriers to COVID-19 vaccination of people prioritised, but hesitant to receive the vaccine.

METHOD

In this qualitative study in Victoria, Australia (February-May 2021), we purposively sampled hesitant adults who were health or aged/disability care workers (n=20), or adults aged 18-69 with comorbidities or aged ≥70 years ('prioritised adults'; n=19). We thematically analysed interviews inductively, then deductively organised themes within the World Health Organization Behavioural and Social Drivers of vaccination model. Two stakeholder workshops (n=12) explored understanding and preferences for communicating risks and benefits. We subsequently formed communication recommendations.

RESULTS

Prioritised adults and health and aged care workers had short- and long-term safety concerns specific to personal circumstances, and felt like "guinea pigs". They saw vaccination as beneficial for individual and community protection and travel. Some health and aged care workers felt insufficiently informed to recommend vaccines, or viewed this as outside their scope of practice. Workshop participants requested interactive materials and transparency from spokespeople about uncertainty. Conclusions and public health implications: Eleven recommendations address communication content, delivery and context to increase uptake and acceptance of COVID-19 vaccines.

Information nudges for influenza vaccination: Evidence from a large-scale cluster-randomized controlled trial in Finland

BACKGROUND

Vaccination is the most effective means of preventing the spread of infectious diseases. Despite the proven benefits of vaccination, vaccine hesitancy keeps many people from getting vaccinated.

METHODS AND FINDINGS

We conducted a large-scale cluster randomized controlled trial in Finland to test the effectiveness of centralized written reminders (distributed via mail) on influenza vaccination coverage. The study included the entire older adult population (aged 65 years and above) in 2 culturally and geographically distinct regions with historically low (31.8%, n = 7,398, mean age 75.5 years) and high (57.7%, n = 40,727, mean age 74.0 years) influenza vaccination coverage. The study population was randomized into 3 treatments: (i) no reminder (only in the region with low vaccination coverage); (ii) an individual-benefits reminder, informing recipients about the individual benefits of vaccination; and (iii) an individual- and social-benefits reminder, informing recipients about the additional social benefits of vaccination in the form of herd immunity. There was no control treatment group in the region with high vaccination coverage as general reminders had been sent in previous years. The primary endpoint was a record of influenza vaccination in the Finnish National Vaccination Register during a 5-month follow-up period (from October 18, 2018 to March 18, 2019). Vaccination coverage after the intervention in the region with historically low coverage was 41.8% in the individual-benefits treatment, 38.9% in the individual- and social-benefits treatment and 34.0% in the control treatment group. Vaccination coverage after the intervention in the region with historically high coverage was 59.0% in the individual-benefits treatment and 59.2% in the individual- and social-benefits treatment. The effect of receiving any type of reminder letter in comparison to control treatment group (no reminder) was 6.4 percentage points (95% CI: 3.6 to 9.1, p < 0.001). The effect of reminders was particularly large among individuals with no prior influenza vaccination (8.8 pp, 95% CI: 6.5 to 11.1, p < 0.001). There was a substantial positive effect (5.3 pp, 95% CI: 2.8 to 7.8, p < 0.001) among the most consistently unvaccinated individuals who had not received any type of vaccine during the 9 years prior to the study. There was no difference in influenza vaccination coverage between the individual-benefit reminder and the individual- and social-benefit reminder (region with low vaccination coverage: 2.9 pp, 95% CI: -0.4 to 6.1, p = 0.087, region with high vaccination coverage: 0.2 pp, 95% CI: -1.0 to 1.3, p = 0.724). Study limitations included potential contamination between the treatments due to information spillovers and the lack of control treatment group in the region with high vaccination coverage.

CONCLUSIONS

In this study, we found that sending reminders was an effective and scalable intervention strategy to increase vaccination coverage in an older adult population with low vaccination coverage. Communicating the social benefits of vaccinations, in addition to individual benefits, did not enhance vaccination coverage. The effectiveness of letter reminders about the benefits of vaccination to improve influenza vaccination coverage may depend on the prior vaccination history of the population.

TRIAL REGISTRATION

AEA RCT registry AEARCTR-0003520 and ClinicalTrials.gov NCT03748160.

Collective Value Promotes the Willingness to Share Pro-Vaccination Messages on Social Media in China: A Randomized Controlled Trial (Preprint)

Background

The proliferation of vaccine misinformation on social media has seriously corrupted the public’s confidence in vaccination. Proactively sharing provaccination messages on social media is a cost-effective way to enhance global vaccination rates and resist vaccine misinformation. However, few strategies for encouraging the public to proactively share vaccine-related knowledge on social media have been developed.

Objective

This research examines the effect of value type (individual vs collective) and message framing (gain vs loss) on influenza vaccination intention (experiment 1) and the willingness to share provaccination messages (experiment 2) among Chinese adults during the COVID-19 pandemic. The primary aim was to evaluate whether messages that emphasized collective value were more effective in increasing the willingness to share than messages that emphasized individual value.

Methods

We enrolled 450 Chinese adults for experiment 1 (n=250, 55.6%) and experiment 2 (n=200, 44.4%). Participants were randomly assigned to individual-gain, individual-loss, collective-gain, or collective-loss conditions with regard to the message in each experiment using the online survey platform’s randomization function. Experiment 1 also included a control group. The primary outcome was influenza vaccination intention in experiment 1 and the willingness to share provaccination messages in experiment 2.

Results

The valid sample included 213 adults in experiment 1 (females: n=151, 70.9%; mean age 29 [SD 9] years; at least some college education: n=202, 94.8%; single: n=131, 61.5%) and 171 adults in experiment 2 (females: n=106, 62.0%; mean age 28 [SD 7] years; at least some college education: n=163, 95.3%; single: n=95, 55.6%). Influenza vaccination intention was stronger in the individual-value conditions than in the collective-value conditions (F_3,166=4.96, P=.03, η²=0.03). The reverse result was found for the willingness to share provaccination messages (F_3,165=6.87, P=.01, η²=0.04). Specifically, participants who received a message emphasizing collective value had a higher intention to share the message than participants who read a message emphasizing individual value (F_3,165=6.87, P=.01, η²=0.04), and the perceived responsibility for message sharing played a mediating role (indirect effect=0.23, 95% lower limit confidence interval [LLCI] 0.41, 95% upper limit confidence interval [ULCI] 0.07). In addition, gain framing facilitated influenza vaccination intention more than loss framing (F_3,166=5.96, P=.02, η²=0.04). However, experiment 2 did not find that message framing affected message-sharing willingness. Neither experiment found an interaction between value type and message framing.

Conclusions

Strengthened individual value rather than collective value is more likely to persuade Chinese adults to vaccinate. However, these adults are more likely to share a message that emphasizes collective rather than individual value, and the perceived responsibility for message sharing plays a mediating role.

A self-administered virtual reality intervention increases COVID-19 vaccination intention

Effective interventions for increasing people's intention to get vaccinated are crucial for global health, especially considering COVID-19. We devised a novel intervention using virtual reality (VR) consisting of a consultation with a general practitioner for communicating the benefits of COVID-19 vaccination and, in turn, increasing the intention to get vaccinated against COVID-19. We conducted a preregistered online experiment with a 2×2 between-participant design. People with eligible VR headsets were invited to install our experimental application and complete the ten minute virtual consultation study at their own discretion. Participants were randomly assigned across two age conditions (young or old self-body) and two communication conditions (with provision of personal benefit of vaccination only, or collective and personal benefit). The primary outcome was vaccination intention (score range 1-100) measured three times: immediately before and after the study, as well as one week later. Five-hundred-and-seven adults not vaccinated against COVID-19 were recruited. Among the 282 participants with imperfect vaccination intentions (<100), the VR intervention increased pre-to-post vaccination intentions across intervention conditions (mean difference 8.6, 95% CI 6.1 to 11.1,p<0.0001). The pre-to-post difference significantly correlated with the vaccination intention one week later, ρ=0.20,p<0.0001. The VR intervention was effective in increasing COVID-19 vaccination intentions both when only personal benefits and personal and collective benefits of vaccination were communicated, with significant retention one week after the intervention. Utilizing recent evidence from health psychology and embodiment research to develop immersive environments with customized and salient communication efforts could therefore be an effective tool to complement public health campaigns.

Trends in COVID-19 vaccination intent from pre- to post-COVID-19 vaccine distribution and their associations with the 5C psychological antecedents of vaccination by sex and age in Japan

Vaccine hesitancy regarding the coronavirus disease 2019 (COVID-19) vaccine is widespread during the COVID-19 pandemic. Many recent studies have reported that the confidence of the vaccination and perceived risk were associated with vaccination intent, yet few studies have focused on other psychological factors. This study aimed to clarify the trends in COVID-19 vaccination intent and to identify the association between the 5C psychological antecedents and COVID-19 vaccination intent by sex and age in Japan. This was a longitudinal study conducted through an Internet-based survey from January 2021 to April 2021 before and after vaccine distribution in Japan, including 2,655 participants recruited by quota sampling. Participants were asked to indicate how likely they were to get vaccinated against COVID-19. In the second survey, the participants responded to questions regarding the 5C psychological antecedents: confidence, complacency, constraints (structural and psychological barriers), calculation (engagement in extensive information searching), and collective responsibility (willingness to protect others). Multiple logistic regression analysis was performed to clarify the association between the 5C psychological antecedents and COVID-19 vaccination intent in the second wave survey. COVID-19 vaccination intent improved from 62.1% to 72.4% after vaccine distribution, but no significant difference was found in young men. Confidence and collective responsibility were positively associated with vaccination intent, and calculation was negatively associated among all generations. COVID-19 vaccination intent may be affected not only by confidence and constraints but also by calculation and collective responsibility, and further research is needed.

Social nudges for vaccination: How communicating herd behaviour influences vaccination intentions

Objectives

This Registered Report attempted to conceptually replicate the finding that communicating herd immunity increases vaccination intentions (Betsch, et al., 2017, Nat. Hum. Behav., 0056). An additional objective was to explore the roles of descriptive social norms (vaccination behaviour of others) and the herd‐immunity threshold (coverage needed to stop disease transmission).

Design

An online experiment with a 2 (herd‐immunity explanation: present vs. absent) × 3 (descriptive norm: high vs. low vs. absent) × 2 (herd‐immunity threshold: present vs. absent) between‐subjects fractional design.

Methods

Sample consisted of 543 people (aged 18–64) residing in the United Kingdom. Participants first received an explanation of herd immunity emphasising social benefits (protecting others) in both textual and animated‐infographic form. Next, they were faced with fictitious information about the disease, the vaccine, their country’s vaccination coverage (80% or 20%), and the herd‐immunity threshold (90%). Vaccination intention was self‐rated.

Results

Compared to the control, communicating social benefits of herd immunity was effective in increasing vaccination intentions (F(1,541) = 6.97, p = .009, Partial Eta‐Squared = 0.013). Communicating the descriptive norm or the herd‐immunity threshold alongside the herd‐immunity explanation demonstrated no observable effect.

Conclusion

Communicating social benefits of herd immunity increased self‐reported vaccination intentions against a fictitious disease, replicating previous findings. Although this result is positive, the practical relevance may be limited. Further research into the effect of social nudges to motivate vaccination is required, particularly with respect to the recent pandemic context and varying levels of vaccine hesitancy.

Prosocial vaccination

Most vaccines not only directly protect vaccinated individuals but also provide a social benefit through community protection. Therefore, vaccination can be considered a prosocial act to protect others. We review the recent empirical evidence on (i) how prosocial concerns relate to vaccination intentions and (ii) promoting prosocial vaccination through explaining community protection or inducing concern for vulnerable others. The available evidence suggests that promoting the prosocial aspect of vaccinations could be a vaccination communication strategy to improve vaccine uptake. We point to several areas in which future research can test the boundary conditions of this approach and increase its effectiveness.

How practice nurses engage with parents during their consultations about the MMR vaccine: a qualitative study

Aim:

We aimed to understand practice nurses’ perceptions about how they engage with parents during consultations concerning the measles, mumps and rubella (MMR) vaccine.

Background:

The incidence of measles is increasing globally. Immunisation is recognised as the most significant intervention to influence global health in modern times, although many factors are known to adversely affect immunisation uptake. Practice nurses are a key member of the primary care team responsible for delivering immunisation. However, little is known how practice nurses perceive this role.

Methods:

Semi-structured interviews were undertaken with 15 practice nurses in England using a qualitative descriptive approach. Diversity in terms of years of experience and range of geographical practice settings were sought. These interviews were recorded, transcribed verbatim and open-coded using qualitative content analysis to manage, analyse and identify themes.

Findings:

Three themes were derived from the data: engaging with parents, the informed practice nurse and dealing with parental concerns: strategies to promote MMR uptake. During their consultations, practice nurses encountered parents who held strong opinions about the MMR vaccine and perceived this to be related to the parents’ socio-demographic background. Practice nurses sought to provide parents with tailored and accurate sources of information to apprise their immunisation decision-making about the MMR vaccine.

Humor and Fear-Two Sides of the Same Coin?: Experimental Evidence on Humor Appeals in Health Communication Related to Childhood Vaccination

Until now, health communication has largely failed to debunk fears and caveats related to vaccination. This study aims to investigate the effects of different text types used in health communication in an experimental study design. A neutrally formulated text was compared to a humorous text using the formula of a fairytale. Overall, the study indicates no additional value in using the humorous format as an innovative and target-group-oriented approach to inform readers about scientific evidence related to vaccination. Although the effects of the two text types do not differ, the credibility of the neutrally formulated text was much more likely to be judged as high. This indicates that the perception of credibility is not the only criterion in health communication leading to knowledge gains and changes in health-related attitudes and behaviors.

The Role of Emotional Competences in Parents' Vaccine Hesitancy

The role of parents’ emotional competencies on vaccine hesitancy and decision making has been seldom examined. Two studies investigated the relationship between parents’ attitudes towards childhood vaccines and self-reported behavior (Study 1) and between parents’ emotional competence and attitudes towards vaccines (Study 2). In Study 1, predictors of temporal, partial, or complete vaccine refusal (having voluntarily postponed/forgone some/all vaccines) were examined in 2778 parents. In Study 2, psychological predictors of the attitude towards vaccines were examined in 593 parents, using the Profile of Emotional Competence and the valence of mental images spontaneously associated with the term “vaccine”. In Study 1, attitudes were aggregated in three independent factors (concerns about vaccine safety; diseases prevented by vaccines; and naturalistic views) that independently predicted vaccine refusal. In Study 2, a significant mediational analysis showed a positive indirect effect of intrapersonal emotional competences on attitudes towards vaccines, through mental images associated with the word “vaccine”. Parents’ intrapersonal emotional competences affected all dimensions of attitudes towards vaccines, suggesting that being able to manage, identify, and recognize one’s own emotions is central to vaccine acceptance. These findings suggest that intervention strategies, rather than stressing the pro-social benefits of vaccinating, should focus on aspects related to one’s own emotions.

Practice nurses' perceptions of their immunization role and strategies used to promote measles, mumps, and rubella vaccine uptake in 2014 - 2018: A qualitative study

AIM

The aim of this study was to explore which aspects of their role practice nurses perceive to be most influential and the strategies they employ to promote the MMR vaccine.

DESIGN

Qualitative study employing in depth interviews.

METHOD

Fifteen London based practice nurses, nine in 2014 and six in 2018, took part in semi-structured interviews that were audio recorded and transcribed verbatim. Qualitative content analysis was used to systematically manage, analyse, and identify themes.

RESULTS

Analysis of data identified aspects of their role practice nurses perceived to be most influential (the themes) including: promoting vaccination, assisting parents' to make informed decisions, and provided insight into how they used specific strategies to achieve these in practice. These themes were consistent over both phases of the study.

CONCLUSION

The findings provide an understanding of: (i) the practice nurses perceptions of the most important aspects of their role when promoting the measles, mumps, and rubella vaccine; and (ii) the strategies they implemented in practice to achieve these. The latter included assisting parents in their immunization decisions and was facilitated by practice nurses engaging with parents to provide relevant evidence to address parent queries, dispel misconceptions and tailor strategies to promote the measles, mumps, and rubella vaccine.

IMPACT

This study addresses the paucity of literature available that specifically explores practice nurses' perceptions of their role concerning the measles, mumps, and rubella vaccine. The findings reveal how practice nurses promote the measles, mumps, and rubella vaccine by identifying strategies to enable parents to make informed decisions. At a time of an increasing incidence of measles, practice nurses have an important public health role in achieving herd immunity levels for measles, mumps, and rubella.

A Web Application About Herd Immunity Using Personalized Avatars: Development Study

BACKGROUND

Herd immunity or community immunity refers to the reduced risk of infection among susceptible individuals in a population through the presence and proximity of immune individuals. Recent studies suggest that improving the understanding of community immunity may increase intentions to get vaccinated.

OBJECTIVE

This study aims to design a web application about community immunity and optimize it based on users' cognitive and emotional responses.

METHODS

Our multidisciplinary team developed a web application about community immunity to communicate epidemiological evidence in a personalized way. In our application, people build their own community by creating an avatar representing themselves and 8 other avatars representing people around them, for example, their family or coworkers. The application integrates these avatars in a 2-min visualization showing how different parameters (eg, vaccine coverage, and contact within communities) influence community immunity. We predefined communication goals, created prototype visualizations, and tested four iterative versions of our visualization in a university-based human-computer interaction laboratory and community-based settings (a cafeteria, two shopping malls, and a public library). Data included psychophysiological measures (eye tracking, galvanic skin response, facial emotion recognition, and electroencephalogram) to assess participants' cognitive and affective responses to the visualization and verbal feedback to assess their interpretations of the visualization's content and messaging.

RESULTS

Among 110 participants across all four cycles, 68 (61.8%) were women and 38 (34.5%) were men (4/110, 3.6%; not reported), with a mean age of 38 (SD 17) years. More than half (65/110, 59.0%) of participants reported having a university-level education. Iterative changes across the cycles included adding the ability for users to create their own avatars, specific signals about who was represented by the different avatars, using color and movement to indicate protection or lack of protection from infectious disease, and changes to terminology to ensure clarity for people with varying educational backgrounds. Overall, we observed 3 generalizable findings. First, visualization does indeed appear to be a promising medium for conveying what community immunity is and how it works. Second, by involving multiple users in an iterative design process, it is possible to create a short and simple visualization that clearly conveys a complex topic. Finally, evaluating users' emotional responses during the design process, in addition to their cognitive responses, offers insights that help inform the final design of an intervention.

CONCLUSIONS

Visualization with personalized avatars may help people understand their individual roles in population health. Our app showed promise as a method of communicating the relationship between individual behavior and community health. The next steps will include assessing the effects of the application on risk perception, knowledge, and vaccination intentions in a randomized controlled trial. This study offers a potential road map for designing health communication materials for complex topics such as community immunity.

Strengthening vaccination programmes and health systems in the European Union: A framework for action

Vaccination is one of the most cost-effective public health interventions. However, the EU is facing increasing outbreaks of vaccine preventable diseases, with some fatal cases of measles. This paper reviews the main factors influencing vaccination uptake, and assesses measures expected to improve vaccination coverage. Obstacles to vaccination include concerns about vaccine safety and side effects, lack of trust, social norms, exposure to rumours and myths, and access barriers. Responses fall into three broad categories. Regulation, including the introduction of mandatory vaccination, can be justified but it is important to be sure that it is an appropriate solution to the existing problem and does not risk unintended consequences. Facilitation involves ensuring that there is an effective vaccination programme, comprehensive in nature, and reducing the many barriers, in terms of cost, distance, and time, to achieving high levels of uptake, especially for marginalised or vulnerable populations. Information is crucial, but whether in the form of public information campaigns or interactions between health workers and target populations, must be designed very carefully to avoid the risk of backfire. There is no universal solution to achieving high levels of vaccine uptake but rather a range or combinations of options. The choice of which to adopt in each country will depend on a detailed understanding of the problem, including which groups are most affected.

Using immersive virtual reality to improve the beliefs and intentions of influenza vaccine avoidant 18-to-49-year-olds: Considerations, effects, and lessons learned

OBJECTIVE

Only one-third of adults 18-49 years old in the United States receive a recommended annual influenza vaccination. This study examined whether supplementing vaccine information statements (VIS) with an immersive virtual reality (VR), short video or electronic pamphlet story designed to convey the community immunity benefits of influenza vaccination would improve influenza vaccine avoidant participants' influenza-related perceptions as well as their influenza vaccination-related beliefs, confidence and intentions.

METHOD

A one-way between-subjects experimental design compared the effects of adding a supplemental education experience prior to VIS exposure with flu vaccine avoidant 18-to-49-year-olds. The 171 participants recruited from the community were randomly assigned to one of three modality treatment conditions [VR, video, or e-pamphlet (i.e., story board presented via electronic tablet)] or a VIS-only control condition.

RESULTS

Compared to the modalities, the VR intervention created a stronger perception of presence (i.e., feeling of "being there" in the story), which, in turn, increased participants' concern about transmitting influenza to others and raised vaccination intention. Increased concern about transmitting influenza to others was associated with positive effects on influenza vaccination-related beliefs, including confidence that one's flu vaccination would protect others. Neither the e-pamphlet nor the video intervention were able to elicit a sense of presence nor were they able to improve the impact of the VIS on the outcome measures.

CONCLUSIONS

Immersive VR has much potential to increase understanding of key immunization concepts, such as community immunity, through creative executions that increase a sense of presence. Given the need to increase influenza vaccination uptake among 18-to-49-year-olds, and the projected growth in VR accessibility and use, additional applications and assessments related to vaccination communication and education are needed and warranted. By increasing the ability to convey key vaccine and immunization concepts, immersive VR could help address vaccination hesitancy and acceptance challenges.