Overview of Tools and Measures Investigating Vaccine Hesitancy in a Ten Year Period: A Scoping Review

A systematic review of measures of healthcare workers' vaccine confidence

Healthcare workers (HCW) perceptions toward vaccines influence patient and community vaccine decision making. In an era of rising vaccine hesitancy, understanding HCW vaccine confidence is critical. This systematic review aims to review instruments that have been validated to measure HCW vaccine confidence. We conducted a search in five databases in June 2023. Data was descriptively synthesized. Twelve articles describing 10 different tools were included. Most tools included dimensions or items on vaccine knowledge (n = 9), safety (n = 8), vaccine usefulness (n = 8), recommendation behavior (n = 8), and self-vaccination practice (n = 7). All, except one study, were conducted in high-income countries. There was variability in the quality of the validation process. There is limited existing literature on development and validation of tools for HCW vaccine confidence. Based on the tools currently available, the Pro-VC-Be tool is the most well validated. Further research needs to include low- and middle-income contexts.

Caregivers' perceptions on routine childhood vaccination: A qualitative study on vaccine hesitancy in a South Brazil state capital

Immunization programs worldwide have been facing challenges in keeping vaccination coverage high. Even though universally known for its robust National Immunization Program, Brazil has also faced significant challenges regarding vaccination coverage. One of the reasons for this is vaccine hesitancy, a complex, multi-causal, and context-specific phenomenon. This qualitative study aims to understand the factors associated with decision-making and the drivers of vaccine hesitancy in Florianopolis, Santa Catarina state capital, regarding caregivers' perceptions of routine childhood vaccination. In-depth interviews were conducted in the Capital city of Santa Catarina State. Families with children up to 6 years old were included. Data were analyzed based on thematic content analysis. Twenty-nine caregivers in 18 families were interviewed. These caregivers were mainly mothers and fathers. Three themes emerged: 1. Access to information and the decision-making process, where we discuss the role of social circles, healthcare workers, and the internet; 2. Individual-institutions power relationships: Perceptions about the State's role and the Health institutions: 3. Reasons and motivations: The senses and meanings behind non-vaccination, where we discuss the drivers of vaccine hesitancy related to risk perception, caregivers' opinions on the medical-pharmaceutical industry, vaccines' composition and their side effects, families' lifestyles and worldviews, and the childhood routine vaccination schedule. The results of this study reaffirm the complexity of the decision-making process in childhood vaccination and further enable a better contextual understanding of the complex and challenging phenomenon of vaccine hesitancy.

A xanthan gum and carbomer-codispersed divalent manganese ion-loaded tannic acid nanoparticle adjuvanted inactivated pseudorabies virus vaccine induces balanced humoral and cellular immune responses

Adjuvants including aluminum adjuvant (Alum) and oil-water emulsion have been widely used in inactivated pseudorabies virus (PRV) vaccines to improve their performance, however, they are not sufficient to protect from PRV infection because of the weak immune response and poor Th1-type immune response. Divalent manganese ion (Mn2+) has been reported to increase the cellular immune response significantly. In this work, a xanthan gum and carbomer-dispersed Mn2+-loaded tannic acid-polyethylene glycol (TPMnXC) nanoparticle colloid is developed and used as an adjuvant to improve the performance of the inactivated PRV vaccine. The good in vitro and in vivo biocompatibility of the developed TPMnXC colloid has been confirmed by the cell viability assay, erythrocyte hemolysis, blood routine analysis, and histological analysis of mouse organs and injection site. The TPMnXC-adjuvanted inactivated PRV vaccine (TPMnXC@PRV) significantly promotes higher and more balanced immune responses indicating with an increased specific total IgG antibody and IgG2a/IgG1 ratio, efficient splenocytes proliferation, and elevated Th1- and Th2-type cytokine secretion than those of control groups. Wild PRV challenge experiment is performed using mice as a model animal, achieving a protection rate of up to 86.67 %, which is much higher than those observed from the commercial Alum. This work not only demonstrates the high potentiality of TPMnXC in practical applications but also provides a new way to develop the Mn2+-loaded nanoadjuvant for veterinary vaccines.

Turkish Adaptation, Reliability, and Validity Study of the Vaccine Acceptance Instrument

This research study aimed to assess the reliability and validity of the Turkish version of the Vaccine Acceptance Instrument (VAI). The VAI is a 20-item Likert-type scale, with responses ranging across seven points. A systematic approach was followed to translate the scale into Turkish, involving translation, expert panel evaluation, back-translation, and pilot testing. The Vaccine Acceptance Instrument and a sociodemographic data form were used for data collection. The reliability of the scale was tested by test-retest analysis, and its internal reliability was examined by Cronbach's alpha test. The factor structure was examined using Exploratory Factor Analysis (EFA). Confirmatory Factor Analysis (CFA) was employed to assess the scale's fit. Overall, 229 participants were included in the study. In test-retest reliability analysis, the intraclass correlation coefficient of the scale was 0.992 (95% CI: 0.987-0.996). The Cronbach's alpha value of the scale was 0.824. A four-factor structure was determined. The model had an acceptable fit [χ2/df = 380.04/164 (2,317) p < 0.001, CFI = 0.91, GFI = 0.90, AGFI = 0.906, NFI = 0.90, RMSEA = 0.076]. The mean total VAI score was 112.71 ± 17.02. The low education level of the mother, being a housewife, and parents not having the COVID-19 vaccine were statistically significantly associated with a low scale score and low vaccine acceptance (p < 0.05). The Turkish adaptation of the VAI demonstrated satisfactory levels of validity and reliability following rigorous testing.

Perspectives in the Development of Tools to Assess Vaccine Literacy

Vaccine literacy (VL) is the ability to find, understand, and evaluate vaccination-related information to make appropriate decisions about immunization. The tools developed so far for its evaluation have produced consistent results. However, some dimensions may be underestimated due to the complexity of factors influencing VL. Moreover, the heterogeneity of methods used in studies employing these tools hinders a comprehensive understanding of its role even more. To overcome these limitations, a path has been sought to propose new instruments. This has necessitated updating earlier literature reviews on VL and related tools, exploring its relationship with vaccine hesitancy (VH), and examining associated variables like beliefs, attitudes, and behaviors towards immunization. Based on the current literature, and supported by the re-analysis of a dataset from an earlier study, we propose a theoretical framework to serve as the foundation for creating future assessment tools. These instruments should not only evaluate the psychological factors underlying the motivational aspect of VL, but also encompass knowledge and competencies. The positioning of VL in the framework at the intersection between sociodemographic antecedents and attitudes, leading to behaviors and outcomes, explains why and how VL can directly or indirectly influence vaccination decisions by countering VH and operating at personal, as well as at organizational and community levels.

The Vaccination Fear Scale (VFS-6): Adaptation, Cross-Cultural Validation, and Invariance among Genders and Six Different Cultures, Applying Classical Test Theory (CTT) and Item Response Theory (IRT)

The coronavirus disease 2019 (COVID-19) pandemic had a meaningful impact on several areas of human activity. With respect to psychological assessment, the requirements to study the fear of vaccination as a means to diminish negative behaviour towards vaccination had been reported. This study aimed to evaluate the factorial invariance of the six-item Vaccination Fear Scale (VFS-6) across individuals and cultures. To achieve this goal, a sample of university students was recruited (n = 2535; mean age = 20.59, SD = 2.04; males: 26.75%, females: 73.25%) from Spain (n = 388; 15.3%), Italy (n = 376; 14.83%), Lebanon (n = 487; 19.21%), Nigeria (n = 561; 22.13%), Turkey (n = 410; 16.17%), and Ukraine (n = 313; 12.34%). The results showed that the most appropriate factorial structure, exhibiting excellent fit indices, was a model with two correlated factors (cognitive symptoms: items 1, 2, and 4; somatic symptoms: items 3, 5, and 6) for both the total sample and individual samples from each country and language (Spanish, Italian, Arabic, English, Turkish, and Ukrainian). Notably, the VFS-6 demonstrated configural, metric, scalar, and strict invariance across sex. Regarding countries and languages, configural invariance was observed between them. Also, metric invariance was observed between Spain, Italy, and Ukraine and between Lebanon, Nigeria, and Turkey, which indicates the presence of two well-differentiated groups of countries and the possibility of inferential analysis between them. Item Response Theory analysis suggested an appropriate level of discrimination and difficulty of the test. These significant findings lay the groundwork for future investigations into vaccination fear across diverse cultural backgrounds, providing valuable insights for addressing vaccination-related concerns worldwide.

Vaccine hesitancy among nursing and midwifery undergraduate students in Switzerland: protocol for an online national study

Background

Vaccine hesitancy is a persistent challenge in public health, exacerbated by the proliferation of anti-vaccine sentiments facilitated by social networks. The COVID-19 pandemic has underscored the importance of addressing vaccine hesitancy, designated by the WHO as a top global health threat. This study explores vaccine hesitancy among nursing and midwifery undergraduate students in Switzerland-a cohort crucial to public health given their future roles as healthcare professionals-with a particular emphasis on the HPV vaccine, which exhibits lower confidence levels compared to other vaccines.

Methods

This study will employ an online questionnaire distributed to nursing and midwifery undergraduate students from various healthcare universities. The questionnaire will collect data on vaccine hesitancy (general confidence in vaccines and specifically in the HPV vaccine), HPV vaccine coverage, socio-demographics, likelihood to recommend vaccines to patients, perception of vaccination education and interest in complementary medicine.

Conclusion

The study's findings will contribute to our understanding of vaccine hesitancy among nursing and midwifery undergraduate students, providing insights that can inform targeted interventions and education strategies to bolster vaccine confidence among future healthcare professionals, thereby enhancing public health efforts.

A social media intervention for communicating vaccine safety in low- and middle-income countries: protocol for a pilot study

Vaccine safety is a concern that continues to drive hesitancy and refusal in populations in low-and-middle income countries (LMICs). Communicating about vaccine safety is a strategy that can successfully change personal and community perceptions and behaviors toward vaccination. The COVID-19 infodemic emergency with the rapid rollout of new vaccines and new technology, demonstrated the need for good and effective vaccine safety communication. The Vaccine Safety Net (VSN), a WHO-led global network of websites that provide reliable information on vaccine safety offers the ideal environment for gathering web and social media analytics for measuring impact of vaccine safety messages. Its members work with a wide range of populations, in different geographic locations and at many levels including national, regional, and local. We propose to undertake a pilot study to evaluate the feasibility of implementing COVID-19 vaccine safety communications with VSN members working in LMICs and to assess the impact of communications on public knowledge, attitudes, and perceptions.

Interventions to Improve Knowledge, Attitudes, and Uptake of Recommended Vaccines during Pregnancy and Postpartum: A Scoping Review

Tetanus, pertussis, influenza, and COVID-19 vaccines are recommended for the prevention of related morbidity and mortality during pregnancy and postpartum. Despite the established benefits of vaccination for prenatal and postnatal women, maternal vaccination is not universally included in routine antenatal programs, especially in low- and middle-income countries. Furthermore, the uptake of recommended vaccines among pregnant and postpartum women remains below optimum globally. This review aimed to map the evidence on interventions to improve knowledge, attitudes, and uptake of recommended vaccines among pregnant and postpartum women. We conducted a comprehensive and systematic search for relevant literature in PubMed, Scopus, Web of Science, EBSCOhost, and Google Scholar. Overall, 29 studies published between 2010 and 2023 were included in this review. The majority (n = 27) of these studies were from high-income countries. A total of 14 studies focused on the influenza vaccine, 6 on the Tdap vaccine, 8 on both influenza and Tdap vaccines, and only one study on the COVID-19 vaccine. Patient-centered interventions predominated the evidence base (66%), followed by provider-focused (7%), health system-focused (10%), and multilevel interventions (17%). Overall, the effect of these interventions on knowledge, attitudes, and uptake of maternal vaccines was variable.

Prospective Attitudes towards Respiratory Syncytial Virus (RSV) Vaccination: Validation of a Survey Instrument among Young Females in Jordan Pending Vaccine Authorization

In May 2023, the U.S. FDA advisors endorsed Pfizer's pregnancy-administered vaccine (branded ABRYSVO) to protect infants from respiratory syncytial virus (RSV) infection. Vaccination can reduce the burden of RSV-related respiratory disease, with previous studies showing its substantial medical and financial burden in Jordan. However, pregnant women may exhibit hesitancy to get vaccinated due to concerns about potential risks to themselves or their fetuses. This study aimed to assess the acceptance of the RSV vaccine among young females and identify the determinants influencing their decision using a newly constructed instrument. A survey instrument was developed and validated, comprising 26 items to measure RSV vaccine acceptance. A cross-sectional study design was employed, with data collection from a sample of females aged 18 to 45 residing in Jordan during 5-6 July 2023, using a convenient approach via an online distributed questionnaire. The final study sample comprised 315 respondents, with 67.6% who have heard of RSV before the study. If the vaccine was safe, effective, and provided freely, 70.2% showed willingness to get the RSV vaccine, 15.2% resisted, and 14.6% were hesitant. Principal component analysis identified six internally consistent sub-scales with the following suggested themes: Advice, Burden, Conspiracy, Dangers, Efficiency, and Fear, comprising 21 items collectively as assigned as the "ABCDEF" scale for RSV vaccine acceptance. RSV vaccine acceptance in this study was associated with the advice and fear constructs. The validated survey instrument successfully captured important determinants of RSV vaccine acceptance among young females. RSV vaccine promotion efforts should focus on the following: enhancing vaccine education, improving trust in healthcare institutions and providers, reducing burdens through resolving cost issues and focusing on the role of social support, addressing safety concerns, and tailoring communication strategies to effectively promote the benefits of the vaccine. These insights can inform public health policies and interventions aiming to promote RSV vaccination and mitigate the burden of RSV-related diseases among infants. Follow-up studies are recommended with pregnant women as the target group to assess their attitude towards RSV vaccination and to confirm the validity of the conceived ABCDEF survey instrument.

Psychometric validation of the Korean versions of the Vaccine Hesitancy Scale and Vaccination Attitudes Examination Scale

PURPOSE

Strategies for reducing vaccine hesitancy and negative attitudes toward vaccination and measures to accurately assess them have been developed worldwide. The Vaccine Hesitancy Scale (VHS) and Vaccination Attitudes Examination Scale (VAX) are reliable and valid tools. This study evaluates the validity and reliability of the Korean versions of the Vaccine Hesitancy Scale (K-VHS) and Vaccination Attitudes Examination Scale (K-VAX).

METHODS

We translated the VHS and VAX into Korean using forward and backward translations and tested their psychometric attributes. We collected data from a sample of 2,292 Koreans, recruited in June 2021 from a large online panel using quotas for age and gender. We used content validity, construct validity with confirmatory factor analysis, concurrent validity, and convergent validity to assess the validity of the scales, and tested their reliability with evaluations of internal consistency and stability.

RESULTS

The K-VHS and K-VAX showed good model fits in the validity tests, with seven items for one factor and 12 items for four factors, respectively. The internal consistency (Cronbach's alpha = 0.94 for the K-VHS, and 0.86 for the K-VAX) and stability (ICC = 0.86 for the K-VHS, and 0.88 for the K-VAX) of the measures indicated that they are reliable.

CONCLUSIONS

Both tools are effective psychometric instruments for assessing vaccine hesitancy and vaccination attitudes in Korean adults. K-VHS and K-VAX would be useful for predicting vaccination behaviors in novel infectious disease contexts and communicating the evidence needed to develop related policies or programs.

First Year of Special Issue "New Insights in Vaccination and Public Health": Opinions and Considerations

Disease prevention and control is the foundation of public health [...].

Progress on innate immune evasion and live attenuated vaccine of pseudorabies virus

Pseudorabies virus (PRV) is a highly infectious disease that can infect most mammals, with pigs as the only natural host, has caused considerable economic losses to the pig husbandry of the world. Innate immunity is the first defense line of the host against the attack of pathogens and is essential for the proper establishment of adaptive immunity. The host uses the innate immune response to against the invasion of PRV; however PRV makes use of various strategies to inhibit the innate immunity to promote the virus replication. Currently, live attenuated vaccine is used to prevent pig from infection with the PRV worldwide, such as Bartha K61. However, a growing number of data indicates that these vaccines do not provide complete protection against new PRV variants that have emerged since late 2011. Here we summarized the interactions between PRV and host innate immunity and the current status of live attenuated PRV vaccines to promote the development of novel and more effective PRV vaccines.

Caregiver Willingness to Vaccinate Children with Pneumococcal Vaccines and to Pay in a Low-Resource Setting in China: A Cross-Sectional Study

To determine the vaccine hesitancy of pneumococcal conjugate vaccines (PCVs) in a low-resource setting in China and to identify associated factors, a face-to-face questionnaire survey was conducted in the city of Guilin, China, from December 2021 to March 2022, which comprised sociodemographic information, attitudes toward vaccines and pneumonia, and PCV13 vaccination willingness and willingness to pay (WTP). Stepwise logistic regression and Tobit regression models were fitted to identify factors associated with PCV13 vaccination willingness and WTP, respectively. In total, 1254 questionnaires were included, of which 899, 254, and 101 participants showed acceptance, hesitancy, and refusal to vaccinate their children with PCV13, respectively. Only 39.07% of participants knew about PCV13 before this survey. A total of 558 (48.40%) participants accepted the full payment of vaccination, and 477 (41.37%) other participants accepted the partial payment, with a median cost of CNY 920.00. Demographics, social and psychological context, and attitudes toward vaccines were all associated with PCV13 vaccination but varied for hesitators and refusers. There is a substantial local demand for vaccinating children with PCV13 and partial payment is widely accepted. More publicity and educational efforts and a socially supportive environment are required to alleviate vaccine hesitancy.