Microarray patches: scratching the surface of vaccine delivery

Perceptions of non-needle-based vaccination devices in the state of Georgia

BACKGROUND

Vaccination is important for controlling infectious disease; however, there are logistical barriers associated with needle and syringe-based vaccination. Non-needle-based vaccination methods could address many of these barriers and are in pre-clinical and clinical development. New technology is sometimes followed by hesitancy, affecting acceptance and uptake, highlighting the importance of understanding the perceptions of vaccine delivery methods by potential vaccine recipients.

METHODS

To understand perceptions of non-needle-based vaccination methods in the state of Georgia, we surveyed 427 Georgia residents. Respondents were asked about their perceptions of vaccines and new medical technology, willingness to accept a non-needle-based vaccine, and whether they would recommend specific vaccination devices.

RESULTS

Race and ethnicity were found to impact vaccine hesitancy and trust in new medical developments hesitancy. Of 427 participants, 29.3 % were more likely to accept non-needle-based devices over needle/syringe, 35.1 % were just as likely to accept, 14.4 % were unsure, and 20.6 % indicated that non-needle-based methods would not make them more likely to receive a vaccine. Race, urbanization, insurance status, vaccine hesitancy, and trust in new medical developments affected willingness to accept a non-needle-based vaccine. Needle/syringe vaccine devices were the most accepted method based on a picture and short description (77.6 %), inhaled vaccine devices were the least recommended (46.8 %); nasal spray (64.3 %), jet injector (60.0 %), skin patch (57.3 %), and oral delivery (54.0 %) were between these values.

CONCLUSIONS

While needle/syringe is the preferred method of vaccination, there are clear preferences among non-needle-based vaccine delivery methods; however, demographic factors that are associated should be considered as these devices move through clinical testing. Our future work will involve in-depth interviews to further identify important themes affecting vaccine acceptance in Georgia. Due to potential hesitancy, we need to strengthen our understanding of themes associated with vaccine perceptions to enable design of accurate and persuasive materials for physicians and patients.

Insect-specific virus platforms for arbovirus vaccine development

Certain insect-specific viruses (ISVs), specifically the mosquito alphaviruses, Eilat and Yada Yada viruses, and orthoflaviviruses, Binjari, Aripo, YN15-283-02 and Chaoyang viruses, have emerged as potential platforms for generation of whole virus vaccines for human and veterinary applications. These ISVs are remarkably tolerant of the substitution of their structural polyproteins with those of alphaviruses and orthoflaviviruses that are pathogenic in humans and/or animals. The resulting ISV-based chimeric vaccines have been evaluated in mouse models and have demonstrated safety and efficacy in non-human primates, crocodiles and pigs. Targets include chikungunya, Venezuelan and eastern equine encephalitis, dengue, Zika, yellow fever, Japanese encephalitis and West Nile viruses. ISV-based chimeric vaccines provide authentically folded tertiary and quaternary whole virion particle structures to the immune system, a key feature for induction of protective antibody responses. These vaccines are manufactured in C6/36 or C7-10 mosquito cell lines, where they grow to high titers, but they do not replicate in vertebrate vaccine recipients. This review discusses the progress of these emerging technologies and addresses challenges related to adjuvanting, safety, and manufacturing.

Beyond the Needle: Innovative Microneedle-Based Transdermal Vaccination

Vaccination represents a critical preventive strategy in the current global healthcare system, serving as an indispensable intervention against diverse pathogenic threats. Although conventional immunization relies predominantly on hypodermic needle-based administration, this method carries substantial limitations, including needle-associated fear, bloodborne pathogen transmission risks, occupational injuries among healthcare workers, waste management issues, and dependence on trained medical personnel. Microneedle technology has emerged as an innovative vaccine delivery system, offering convenient, effective, and minimally invasive administration. These microscale needle devices facilitate targeted antigen delivery to epidermal and dermal tissues, where abundant populations of antigen-presenting cells, specifically Langerhans and dermal dendritic cells, provide robust immunological responses. Multiple research groups have extensively investigated microneedle-based vaccination strategies. This transdermal delivery technique offers several advantages, notably circumventing cold-chain requirements and enabling self-administration. Numerous preclinical investigations and clinical trials have demonstrated the safety profile, immunogenicity, and patient acceptance of microneedle-mediated vaccine delivery across diverse immunization applications. This comprehensive review examines the fundamental aspects of microneedle-based immunization, including vaccination principles, transcutaneous immunization strategies, and microneedle-based transdermal delivery-including classifications, advantages, and barriers. Furthermore, this review addresses critical technical considerations, such as treatment efficacy, application methodologies, wear duration, dimensional optimization, manufacturing processes, regulatory frameworks, and sustainability considerations, followed by an analysis of the future perspective of this technology.

Amplifying youth voices: young people's recommendations for policy and practice to enhance vaccine acceptability

BACKGROUND

The COVID-19 pandemic has underscored the need for increased vaccine availability and uptake, with vaccine hesitancy posing a significant barrier, particularly among young adults. Evidence from various countries highlight high levels of hesitancy among young people, necessitating targeted interventions. Engaging young adults as key stakeholders in shaping public health strategies is crucial, as their perspectives can enhance vaccine acceptance. This study aimed to assess the overall acceptability of the COVID-19 vaccine among young people and to explore the factors influencing their willingness or reluctance to be vaccinated now and in the future.

METHODS

This study used qualitative data from 165 young adults in Nigeria, South Africa, and Zambia, to explore their suggestions for policies and strategies aimed at enhancing the acceptance of the Covid-19 vaccination among their age group. Data collection involved focus groups and interviews that explored participants' perceptions and recommendations regarding COVID-19 vaccination acceptability. Thematic analysis was used to analyse the data.

RESULTS

Thematic analysis identified several factors influencing vaccine acceptability among young people and suggested recommendations to improve it. The themes included developing targeted communication strategies for accurate vaccine information, offering alternative vaccination methods, promoting vaccine education in schools, and using trusted public figures to share accurate information.

CONCLUSIONS

Persistent dissatisfaction with vaccine information dissemination underscores the need for more targeted communication strategies among young adults. Recommendations include developing non-injection vaccine options, incorporating vaccine education into school curricula and community programs, and leveraging influential public figures to build credibility. These insights are valuable for designing future programs to enhance vaccine acceptance among adolescents.

An Application of an Initial Full Value of Vaccine Assessment Methodology to Measles-Rubella MAPs for Use in Low- and Middle-Income Countries

Measles and rubella micro-array patches (MR-MAPs) are a promising innovation to address limitations of the current needle and syringe (N&S) presentation due to their single-dose presentation, ease of use, and improved thermostability. To direct and accelerate further research and interventions, an initial full value vaccine assessment (iFVVA) was initiated prior to MR-MAPs entering phase I trials to quantify their value and identify key data gaps and challenges. The iFVVA utilized a mixed-methods approach with rapid assessment of literature, stakeholder interviews and surveys, and quantitative data analyses to (i) assess global need for improved MR vaccines and how MR-MAPs could address MR problem statements; (ii) estimate costs and benefits of MR-MAPs; (iii) identify the best pathway from development to delivery; and (iv) identify outstanding areas of need where stakeholder intervention can be helpful. These analyses found that if MR-MAPs are broadly deployed, they can potentially reach an additional 80 million children compared to the N&S presentation between 2030-2040. MR-MAPs can avert up to 37 million measles cases, 400,000 measles deaths, and 26 million disability-adjusted life years (DALYs). MR-MAPs with the most optimal product characteristics of low price, controlled temperature chain (CTC) properties, and small cold chain volumes were shown to be cost saving for routine immunization (RI) in low- and middle-income countries (LMICs) compared to N&S. Uncertainties about price and future vaccine coverage impact the potential cost-effectiveness of introducing MR-MAPs in LMICs, indicating that it could be cost-effective in 16-81% of LMICs. Furthermore, this iFVVA highlighted the importance of upfront donor investment in manufacturing set-up and clinical studies and the critical influence of an appropriate price to ensure country and manufacturer financial sustainability. To ensure that MR-MAPs achieve the greatest public health benefit, MAP developers, vaccine manufacturers, donors, financiers, and policy- and decision-makers will need close collaboration and open communications.

Developing and validating a scale to measure the perceptions of safety, usability and acceptability of microarray patches for vaccination: a study protocol

Background

Vaccination is a fundamental tenet of public and population health. Several barriers to vaccine uptake exist, exacerbated post-COVID-19, including misconceptions about vaccine efficacy and safety, vaccine hesitancy, vaccine inequity, costs, religious beliefs, and insufficient education and guidance for healthcare professionals. Vaccine uptake may be aided using microarray patches (MAPs) due to reduced pain, no hypodermic needle, enhanced thermostability, and potential for self and lay administration.

Objectives

This protocol outlines the development of a scale that aims to accurately measure the perceived safety, usability, and acceptability of MAPs for vaccination among laypeople, MAP recipients, clinicians, and parents or guardians of children.

Methods and analysis

This study will follow three phases of scale development and validation, including (1) item development, (2) scale development, and (3) scale evaluation. Inductive (interviews) and deductive methods (literature searches) will be used to develop scale items, which experts from target populations will assess through an online survey. Cognitive interviews will be conducted to observe their processes of answering the draft survey. Thematic analysis will be conducted to analyse qualitative data. Lastly, four surveys will be administered online to our target populations over two time points to determine their repeatability. Exploratory and confirmatory factor analyses, Cronbach's alpha, and construct validity will be performed.

Ethics

This study was approved by Metro South Health (HREC/2021/QMS/81653) and Western Sydney Local Health District (2023/ETH00705) Human Research Ethics Committees.

Discussion

The scale will support a standardised approach to assessing the social and behavioural aspects of MAP vaccines, enabling comparison of outcomes across studies. Once validated, this scale will assist vaccination programmes in developing effective strategies for integrating MAPs and overcoming barriers to vaccination. This includes improving vaccine equity and accessibility, especially in lower- and middle-income countries and rural or remote locations.

Enhancement of cellular immunity following needle-free vaccination of mice with SARS-CoV-2 spike protein

The COVID-19 pandemic has highlighted the need for vaccines capable of providing rapid and robust protection. One way to improve vaccine efficacy is delivery via microarray patches, such as the Vaxxas high-density microarray patch (HD-MAP). We have previously demonstrated that delivery of a SARS-CoV-2 protein vaccine candidate, HexaPro, via the HD-MAP induces potent humoral immune responses. Here, we investigate the cellular responses induced by HexaPro HD-MAP vaccination. We found that delivery via the HD-MAP induces a type one biassed cellular response of much greater magnitude as compared to standard intramuscular immunization.