Economic impact of thermostable vaccines

Clinical and Preclinical Methods of Heat-Stabilization of Human Vaccines

Vaccines have historically faced challenges regarding stability, especially in regions lacking a robust cold chain infrastructure. This review delves into established and emergent techniques to improve the thermostability of vaccines. We discuss the widely practiced lyophilization method, effectively transforming liquid vaccine formulations into a solid powdered state, enhancing storage and transportation ability. However, potential protein denaturation during lyophilization necessitates alternative stabilization methods. Cryoprotectants, namely, starch and sugar molecules, have shown promise in protecting vaccine antigens and adjuvants from denaturation and augmenting the stability of biologics during freeze-drying. Biomineralization, a less studied yet innovative approach, utilizes inorganic or organic-inorganic hybrids to encapsulate biological components of vaccines with a particular emphasis on metal-organic coordination polymers. Encapsulation in organic matrices to form particles or microneedles have also been studied in the context of vaccine thermostability, showing some ability to store outside the cold-chain. Unfortunately, few of these techniques have advanced to clinical trials that evaluate differences in storage conditions. Nonetheless, early trials suggest that alternative storage techniques are viable and emphasize the need for more comprehensive studies. This review underscores the pressing need for heat-stable vaccines, especially in light of the increasing global distribution challenges. Combining traditional methods with novel approaches holds promise for the future adaptability of vaccine distribution and use.

Multi-epitope vaccine candidates based on mycobacterial membrane protein large (MmpL) proteins against Mycobacterium ulcerans

Buruli ulcer (BU) is a neglected tropical disease. It is caused by the bacterium Mycobacterium ulcerans and is characterized by skin lesions. Several studies were performed testing the Bacillus Calmette-Guérin (BCG) vaccine in human and animal models and M. ulcerans-specific vaccines in animal models. However, there are currently no clinically accepted vaccines to prevent M. ulcerans infection. The aim of this study was to identify T-cell and B-cell epitopes from the mycobacterial membrane protein large (MmpL) proteins of M. ulcerans. These epitopes were analysed for properties including antigenicity, immunogenicity, non-allergenicity, non-toxicity, population coverage and the potential to induce cytokines. The final 8 CD8+, 12 CD4+ T-cell and 5 B-cell epitopes were antigenic, non-allergenic and non-toxic. The estimated global population coverage of the CD8+ and CD4+ epitopes was 97.71%. These epitopes were used to construct five multi-epitope vaccine constructs with different adjuvants and linker combinations. The constructs underwent further structural analyses and refinement. The constructs were then docked with Toll-like receptors. Three of the successfully docked complexes were structurally analysed. Two of the docked complexes successfully underwent molecular dynamics simulations (MDS) and post-MDS analysis. The complexes generated were found to be stable. However, experimental validation of the complexes is required.

A robust optimization problem for drone-based equitable pandemic vaccine distribution with uncertain supply

Widespread vaccination is the only way to overcome the COVID-19 global crisis. However, given the vaccine scarcity during the early outbreak of the pandemic, ensuring efficient and equitable distribution of vaccines, particularly in rural areas, has become a significant challenge. To this end, this study develops a two-stage robust vaccine distribution model that addresses the supply uncertainty incurred by vaccine shortages. The model aims to optimize the social and economic benefits by jointly deciding vaccination facility location, transportation capacity, and reservation plan in the first stage, and rescheduling vaccinations in the second stage after the confirmation of uncertainty. To hedge vaccine storage and transportation difficulties in remote areas, we consider using drones to deliver vaccines in appropriate and small quantities to vaccination points. Two tailored column-and-constraint generation algorithms are proposed to exactly solve the robust model, in which the subproblems are solved via the vertex traversal and the dual methods, respectively. The superiority of the dual method is further verified. Finally, we use real-world data to demonstrate the necessity to account for uncertain supply and equitable distribution, and analyze the impacts of several key parameters. Some managerial insights are also produced for decision-makers.

Stressed stability and protective efficacy of lead lyophilized formulations of ID93+GLA-SE tuberculosis vaccine

With the recent exception of coronavirus disease 2019 (COVID-19), tuberculosis (TB) causes more deaths globally than any other infectious disease, and approximately 1/3 of the world's population is infected with Mycobacterium tuberculosis (Mtb). However, encouraging progress in TB vaccine development has been reported, with approximately 50% efficacy achieved in Phase 2b clinical testing of an adjuvanted subunit TB vaccine candidate. Nevertheless, current lead vaccine candidates require cold-chain transportation and storage. In addition to temperature stress, vaccines may be subject to several other stresses during storage and transport, including mechanical, photochemical, and oxidative stresses. Optimal formulations should enable vaccine configurations with enhanced stability and decreased sensitivity to physical and chemical stresses, thus reducing reliance on the cold chain and facilitating easier worldwide distribution. In this report, we describe the physicochemical stability performance of three lead thermostable formulations of the ID93 + GLA-SE TB vaccine candidate under various stress conditions. Moreover, we evaluate the impact of thermal stress on the protective efficacy of the vaccine formulations. We find that formulation composition impacts stressed stability performance, and our comprehensive evaluation enables selection of a lead single-vial lyophilized candidate containing the excipient trehalose and Tris buffer for advanced development.

A thermostable, dry formulation inactivated Hikojima whole cell/cholera toxin B subunit oral cholera vaccine

The feared diarrheal disease cholera remains an important global health problem. Use of oral cholera vaccine (OCV) from a global stockpile against both epidemic and endemic cholera is a cornerstone in the World Health Organisations (WHOs) global program for "Ending cholera by 2030". Three liquid inactivated whole-cell OCVs (Dukoral®, Shanchol^TM, and Euvichol-Plus®) are WHO prequalified and have proved to be safe and effective. However, their multicomponent composition and cold-chain requirement increase manufacturing, storage and transport costs. Shanchol^TM and Euvichol-Plus® OCVs used in WHOs global vaccine stockpile also lack the protective cholera toxin B-subunit (CTB) antigen present in Dukoral®, which results in suboptimal efficacy. WHOs Global Task Force on Cholera Control (GTFCC) has identified a thermostable, dry formulation vaccine as a priority for further OCV development. We describe here the development of such a vaccine, based on a lyophilized mixture of a single strain of formalin-killed Hikojima bacteria together with a low-cost, recombinantly produced CTB. The new vaccine, which is easy and inexpensive to manufacture, could be stored for at least 26 months at 25 °C and for at least 8 months at 40 °C with preservation of cell morphology and with no loss of protective Ogawa and Inaba lipopolysaccharides or CTB. It also proved to be well tolerated and to have equivalent oral immunogenicity in mice as Shanchol^TM and Dukoral® OCVs with regard to both serum and intestinal-mucosal antibody responses.

When increasing vegetable production may worsen food availability gaps: A simulation model in India

Translating agricultural productivity into food availability depends on food supply chains. Agricultural policy and research efforts promote increased horticultural crop production and yields, but the ability of low-resource food supply chains to handle increased volumes of perishable crops is not well understood. This study developed and used a discrete event simulation model to assess the impact of increased production of potato, onion, tomato, brinjal (eggplant), and cabbage on vegetable supply chains in Odisha, India. Odisha serves as an exemplar of vegetable supply chain challenges in many low-resource settings. Model results demonstrated that in response to increasing vegetable production 1.25-5x baseline amounts, demand fulfillment at the retail level fluctuated by + 3% to -4% from baseline; in other words, any improvements in vegetable availability for consumers were disproportionately low compared to the magnitude of increased production, and in some cases increased production worsened demand fulfillment. Increasing vegetable production led to disproportionately high rates of postharvest loss: for brinjal, for example, doubling agricultural production led to a 3% increase in demand fulfillment and a 19% increase in supply chain losses. The majority of postharvest losses occurred as vegetables accumulated and expired during wholesale-to-wholesale trade. In order to avoid inadvertently exacerbating postharvest losses, efforts to address food security through agriculture need to ensure that low-resource supply chains can handle increased productivity. Supply chain improvements should consider the constraints of different types of perishable vegetables, and they may need to go beyond structural improvements to include networks of communication and trade.

Safety and immunogenicity of a thermostable ID93 + GLA-SE tuberculosis vaccine candidate in healthy adults

Adjuvant-containing subunit vaccines represent a promising approach for protection against tuberculosis (TB), but current candidates require refrigerated storage. Here we present results from a randomized, double-blinded Phase 1 clinical trial (NCT03722472) evaluating the safety, tolerability, and immunogenicity of a thermostable lyophilized single-vial presentation of the ID93 + GLA-SE vaccine candidate compared to the non-thermostable two-vial vaccine presentation in healthy adults. Participants were monitored for primary, secondary, and exploratory endpoints following intramuscular administration of two vaccine doses 56 days apart. Primary endpoints included local and systemic reactogenicity and adverse events. Secondary endpoints included antigen-specific antibody (IgG) and cellular immune responses (cytokine-producing peripheral blood mononuclear cells and T cells). Both vaccine presentations are safe and well tolerated and elicit robust antigen-specific serum antibody and Th1-type cellular immune responses. Compared to the non-thermostable presentation, the thermostable vaccine formulation generates greater serum antibody responses (p < 0.05) and more antibody-secreting cells (p < 0.05). In this work, we show the thermostable ID93 + GLA-SE vaccine candidate is safe and immunogenic in healthy adults.

Lyophilization Process Engineering and Thermostability of ID93 + GLA-SE, a Single-Vial Adjuvanted Subunit Tuberculosis Vaccine Candidate for Use in Clinical Studies

Promising clinical efficacy results have generated considerable enthusiasm for the potential impact of adjuvant-containing subunit tuberculosis vaccines. The development of a thermostable tuberculosis vaccine formulation could have significant benefits on both the cost and feasibility of global vaccine distribution. The tuberculosis vaccine candidate ID93 + GLA-SE has reached Phase 2 clinical testing, demonstrating safety and immunogenicity as a two-vial point-of-care mixture. Earlier publications have detailed efforts to develop a lead candidate single-vial lyophilized thermostable ID93 + GLA-SE vaccine formulation. The present report describes the lyophilization process development and scale-up of the lead candidate thermostable ID93 + GLA-SE composition. The manufacture of three full-scale engineering batches was followed by one batch made and released under current Good Manufacturing Practices (cGMP). Up to 4.5 years of stability data were collected. The cGMP lyophilized ID93 + GLA-SE passed all manufacturing release test criteria and maintained stability for at least 3 months when stored at 37°C and up to 24 months when stored at 5°C. This work represents the first advancement of a thermostable adjuvant-containing subunit tuberculosis vaccine to clinical testing readiness.

Vaccine cold chain management and cold storage technology to address the challenges of vaccination programs

The outbreaks of infectious diseases that spread across countries have generally existed for centuries. An example is the occurrence of the COVID-19 pandemic in 2020, which led to the loss of lives and economic depreciation. One of the essential ways of handling the spread of viruses is the discovery and administration of vaccines. However, the major challenges of vaccination programs are associated with the vaccine cold chain management and cold storage facilities. This paper discusses how vaccine cold chain management and cold storage technology can address the challenges of vaccination programs. Specifically, it examines different systems for preserving vaccines in either liquid or frozen form to help ensure that they are not damaged during distribution from manufacturing facilities. Furthermore, A vaccine is likely to provide very low efficacy when it is not properly stored. According to preliminary studies, the inability to store vaccine properly is partly due to the incompetency of many stakeholders, especially in technical matters. The novelty of this study is to thoroughly explore cold storage technology for a faster and more comprehensive vaccine distribution hence it is expected to be one of the reference and inspiration for stakeholders.

Thermostable Vaccines in Veterinary Medicine: State of the Art and Opportunities to Be Seized

The COVID-19 pandemic has highlighted the weakness of the vaccine supply chain, and the lack of thermostable formulations is one of its major limitations. This study presents evidence from peer-reviewed literature on the development of thermostable vaccines for veterinary use. A systematic review and meta-analysis were performed to evaluate the immunogenicity and/or the efficacy/effectiveness of thermostable vaccines against infectious diseases. The selected studies (n = 78) assessed the vaccine’s heat stability under different temperature conditions and over different periods. Only one study assessed the exposure of the vaccine to freezing temperatures. Two field studies provided robust evidence on the immunogenicity of commercial vaccines stored at temperatures far in excess of the manufacturer’s recommended cold-chain conditions. The drying process was the most-used method to improve the vaccine’s thermostability, along with the use of different stabilizers. The pooled vaccine efficacy was estimated to be high (VE = 69%), highlighting the importance of vaccination in reducing the economic losses due to the disease impact. These findings provide evidence on the needs and benefits of developing a portfolio of heat- and freeze-stable veterinary vaccines to unleash the true potential of immunization as an essential component of improved animal health and welfare, reduce the burden of certain zoonotic events and thus contribute to economic resilience worldwide.

Optimization methods for large-scale vaccine supply chains: a rapid review

Global vaccine revenues are projected at $59.2 billion, yet large-scale vaccine distribution remains challenging for many diseases in countries around the world. Poor management of the vaccine supply chain can lead to a disease outbreak, or at worst, a pandemic. Fortunately, a large number of those challenges, such as decision-making for optimal allocation of resources, vaccination strategy, inventory management, among others, can be improved through optimization approaches. This work aims to understand how optimization has been applied to vaccine supply chain and logistics. To achieve this, we conducted a rapid review and searched for peer-reviewed journal articles, published between 2009 and March 2020, in four scientific databases. The search resulted in 345 articles, of which 25 unique studies met our inclusion criteria. Our analysis focused on the identification of article characteristics such as research objectives, vaccine supply chain stage addressed, the optimization method used, whether outbreak scenarios were considered, among others. Approximately 64% of the studies dealt with vaccination strategy, and the remainder dealt with logistics and inventory management. Only one addressed market competition (4%). There were 14 different types of optimization methods used, but control theory, linear programming, mathematical model and mixed integer programming were the most common (12% each). Uncertainties were considered in the models of 44% of the studies. One resulting observation was the lack of studies using optimization for vaccine inventory management and logistics. The results provide an understanding of how optimization models have been used to address challenges in large-scale vaccine supply chains.

A hybrid approach based on ELECTRE III ‐genetic algorithm and TOPSIS method for selection of optimal COVID ‐19 vaccines

COVID‐19 pandemic poses unprecedented challenges to the world health system, prompting academics and health professionals to develop appropriate solutions. Researchers reported different COVID‐19 vaccines introduced by institutions and companies around the globe, which are at different stages of development. However, research developing an integrated framework for selecting and ranking the optimal potential vaccine against COVID‐19 is minimal. This paper aimed to fill this gap by using a hybrid methodology based on ELimination Et Choice Translating REality III (ELECTRE III)–Genetic Algorithm (GA) and Technique of Order Preference Similarity to the Ideal Solution (TOPSIS) approach to select the optimal SARS‐CoV‐2 vaccine. ELECTRE III method yields a fathomable analysis of the concordance index, while GA is known for its ability to disaggregate decision‐making preferences from holistic decisions. TOPSIS is preferred for picking an ideal and an anti‐ideal solution. Thus, combining ELECTRE III‐GA and TOPSIS is considered the best model to assess vaccines against the pandemic. The results confirm that the best vaccines rely on a high level of safety, efficacy, and availability. Our developed evaluation framework can help healthcare professionals and researchers gain research information and make critical decisions regarding potential vaccines against the disease.

A systems map of the economic considerations for vaccination: Application to hard-to-reach populations

BACKGROUND

Understanding the economics of vaccination is essential to developing immunization strategies that can be employed successfully with limited resources, especially when vaccinating populations that are hard-to-reach.

METHODS

Based on the input from interviews with 24 global experts on immunization economics, we developed a systems map of the mechanisms (i.e., necessary steps or components) involved in vaccination, and associated costs and benefits, focused at the service delivery level. We used this to identify the mechanisms that may be different for hard-to-reach populations.

RESULTS

The systems map shows different mechanisms that determine whether a person may or may not get vaccinated and the potential health and economic impacts of doing so. The map is divided into two parts: 1) the costs of vaccination, representing each of the mechanisms involved in getting vaccinated (n = 23 vaccination mechanisms), their associated direct vaccination costs (n = 18 vaccination costs), and opportunity costs (n = 5 opportunity costs), 2) the impact of vaccination, representing mechanisms after vaccine delivery (n = 13 impact mechanisms), their associated health effects (n = 10 health effects for beneficiary and others), and economic benefits (n = 13 immediate and secondary economic benefits and costs). Mechanisms that, when interrupted or delayed, can result in populations becoming hard-to-reach include getting vaccines and key stakeholders (e.g., beneficiaries/caregivers, vaccinators) to a vaccination site, as well as vaccine administration at the site.

CONCLUSION

Decision-makers can use this systems map to understand where steps in the vaccination process may be interrupted or weak and identify where gaps exist in the understanding of the economics of vaccination. With improved understanding of system-wide effects, this map can help decision-makers inform targeted interventions and policies to increase vaccination coverage in hard-to-reach populations.

Micro array patch (MAP) for the delivery of thermostable vaccines in Australia: A cost/benefit analysis

BACKGROUND

It is anticipated that transforming the vaccine supply chain from syringe-and-needle to thermostable vaccines enabled by Micro Array Patch (MAP) will result in reduced supply chain costs as well as reduced wastes (environmental impact) and improved safety. This paper provides a thorough cost comparison of the conventional syringe-and-needle vaccine supply chain versus the MAP vaccine supply chain for influenza vaccine delivery in Australia.

OBJECTIVE

To determine the potential cost implications and general benefits of replacing syringe-and-needle flu vaccine with MAP-enabled thermostable flu vaccine in Australia.

METHODS

We first provide a snapshot of the existing flu vaccine supply chain in Australia including its limitations and opportunities for improvement. Data/information is collected through interviewing the key stakeholders across vaccine supply chain including vaccine manufacturers, logistics providers, clinics, hospitals, and pharmacies. A cost/benefit analysis of the anticipated supply chain of the MAP-enabled vaccine will reveal the opportunities and challenges of supply chain transformation for flu vaccine delivery in Australia.

FINDINGS

Our high-level practice-informed cost/benefit analysis identifies cold chain removal as an important source of cost saving, but administrative cost savings appear to be even more significant (e.g., time saving for nurses and those involved in cold chain management). Our analysis also identifies the key benefits and limitations of vaccine supply chain transformation in Australia.

CONCLUSION

We conclude that the benefits of moving from syringe-and-needle vaccines to thermostable MAP-delivered vaccines are beyond transportation and storage cost saving. Potential benefits through cost saving, waste reduction, and service level improvement are discussed along with various safety and wellbeing consequences as well as directions for future research in this area.

Transforming the vaccine supply chain in Australia: Opportunities and challenges

BACKGROUND

Analyzing potential benefits of thermostable vaccines delivered through Micro Array Patch (MAP) has received great attention in low and middle-income countries. The experience may or may not be the same in developed countries where the infrastructure is more developed. It is anticipated that transforming the vaccine supply chain from syringe-and-needle to thermostable MAP-delivered vaccines will result in reduced supply chain costs - including manufacturing/supply, logistics/distribution, and administration costs - as well as reduced wastes and improved safety. This paper provides an end-to-end supply chain analysis comparing the key aspects (cost, safety and environmental aspects) of the conventional syringe-and-needle vaccine supply chain with those of the MAP vaccine supply chain for influenza vaccine delivery in Australia. Directions for future research in this area will be provided.

OBJECTIVE

To determine the potential supply chain impacts of replacing syringe-and-needle flu vaccine with MAP-enabled thermostable flu vaccine in Australia.

METHODS

We analyze the current flu vaccine supply chain in Australia to identify practical limitations and opportunities for improvement. Data/information is collected through interviewing the key stakeholders across vaccine supply chain including vaccine manufacturers, logistics providers, clinics, hospitals, and pharmacies.

FINDINGS

A detailed practice-informed analysis is completed on the key operations of the flu vaccine supply chain. Barriers and limitations of the conventional flu vaccine are discussed, along with potential improvements that can be achieved through the implementation of MAP-enabled flu vaccine delivery. We discuss how technology-driven innovations can help advance vaccine supply chains, improve vaccine visibility, reduce wastes, and enable informed decision-making.

CONCLUSION

We find that the benefits of moving from syringe-and-needle vaccines to thermostable MAP-delivered vaccines are beyond transportation and storage cost saving. Potential benefits through cost saving, waste reduction, and service level improvement are discussed along with various safety and wellbeing consequences followed by directions for future research in this area.

Development of thermostable vaccine adjuvants

INTRODUCTION

The importance of vaccine thermostability has been discussed in the literature. Nevertheless, the challenge of developing thermostable vaccine adjuvants has sometimes not received appropriate emphasis. Adjuvants comprise an expansive range of particulate and molecular compositions, requiring innovative thermostable formulation and process development approaches.

AREAS COVERED

Reports on efforts to develop thermostable adjuvant-containing vaccines have increased in recent years, and substantial progress has been made in enhancing the stability of the major classes of adjuvants. This narrative review summarizes the current status of thermostable vaccine adjuvant development and looks forward to the next potential developments in the field.

EXPERT OPINION

As adjuvant-containing vaccines become more widely used, the unique challenges associated with developing thermostable adjuvant formulations merit increased attention. In particular, more focused efforts are needed to translate promising proof-of-concept technologies and formulations into clinical products.

Lyophilized yeast powder for adjuvant free thermostable vaccine delivery

Thermolabile nature of commercially available vaccines necessitates their storage, transportation, and dissemination under refrigerated condition. Maintenance of continuous cold chain at every step increases the final cost of vaccines. Any breach in the cold chain even for a short duration results in the need to discard the vaccines. As a result, there is a pressing need for the development of thermostable vaccines. In this proof-of-concept study, we showed that E. coli curli-green fluorescent fusion protein remains stable in freeze-dried yeast powder for more than 18 and 12 months when stored at 30 °C and 37 °C respectively. Stability of the heterologous protein remains unaffected during the process of heat-inactivation and lyophilization. The mass of lyophilized yeast powder remains almost unchanged during the entire period of storage and expressed protein remains intact even after two cycles of freeze and thaws. The protease-deficient strain appears ideal for the development of whole recombinant yeast-based vaccines. The cellular abundance of expressed antigen in dry powder after a year was comparable to freshly lyophilized cells. Scanning electron microscopy showed the intact nature of cells in powdered form even after a year of storage at 30 °C. Observation made in this study showed that freeze-dry yeast powder can play a vital role in the development of thermostable vaccines.

Key Points

• Yeast-based vaccines can overcome problem of cold chain associated with conventional vaccines

• Lyophilized yeast powder can be a simple way for long-term storage of immunogen(s)

• Protease deficient strain is important for whole recombinant yeast-based vaccines

How the use of vaccines outside the cold chain or in controlled temperature chain contributes to improving immunization coverage in low- and middle-income countries (LMICs): A scoping review of the literature

Background

Most vaccines are recommended for storage at temperatures of +2°C to +8°C to maintain potency. Immunization supply chain bottlenecks constraints reaching populations with life-saving vaccines. The World Health Organization permits the use of vaccines outside the cold chain as "controlled temperature chain (CTC)" upon meeting certain conditions and has set targets to license more vaccines CTC by 2020.

Objectives

This scoping review aims to explore and synthesize the evidence in the literature on how the use of vaccines outside the cold chain or in a controlled temperature chain increases immunization coverage in low and middle-income countries (LMICs), with a focus on the timelines of the Global Vaccine Action Plan (2011-2020).

Methods

A systematic search of three online databases (PubMed, Embase, and Web of Science) due to their broad coverage of global health sciences retrieved 173 original peer-reviewed articles, of which 13 were included in the review having met our inclusion criteria.

Results

The majority of the studies were conducted in Africa (n = 9), followed by Asia (n = 3), and the least in the Pacific (n = 1). The different study designs captured included four non-randomized trials, three randomized trials, two simulation models, two cross-sectional studies, and one cohort study. Reported benefits included increased coverage, logistical ease, cost savings while vaccines remain potent.

Conclusion

Currently, only two vaccines have been licensed to be stored CTC. More needs to be done to get additional vaccines licensed for CTC and disseminate operational guidance to operationalize its use in low- and middle-income countries.

Polymeric Nanoparticle-Based Vaccine Adjuvants and Delivery Vehicles

As vaccine formulations have progressed from including live or attenuated strains of pathogenic components for enhanced safety, developing new adjuvants to more effectively generate adaptive immune responses has become necessary. In this context, polymeric nanoparticles have emerged as a promising platform with multiple advantages, including the dual capability of adjuvant and delivery vehicle, administration via multiple routes, induction of rapid and long-lived immunity, greater shelf-life at elevated temperatures, and enhanced patient compliance. This comprehensive review describes advances in nanoparticle-based vaccines (i.e., nanovaccines) with a particular focus on polymeric particles as adjuvants and delivery vehicles. Examples of the nanovaccine approach in respiratory infections, biodefense, and cancer are discussed.

Applications of Nanovaccines for Disease Prevention in Cattle

Vaccines are one of the most important tools available to prevent and reduce the incidence of infectious diseases in cattle. Despite their availability and widespread use to combat many important pathogens impacting cattle, several of these products demonstrate variable efficacy and safety in the field, require multiple doses, or are unstable under field conditions. Recently, nanoparticle-based vaccine platforms (nanovaccines) have emerged as promising alternatives to more traditional vaccine platforms. In particular, polymer-based nanovaccines provide sustained release of antigen payloads, stabilize such payloads, and induce enhanced antibod- and cell-mediated immune responses, both systemically and locally. To improve vaccine administrative strategies and efficacy, they can be formulated to contain multiple antigenic payloads and have the ability to protect fragile proteins from degradation. Nanovaccines are also stable at room temperature, minimizing the need for cold chain storage. Nanoparticle platforms can be synthesized for targeted delivery through intranasal, aerosol, or oral administration to induce desired mucosal immunity. In recent years, several nanovaccine platforms have emerged, based on biodegradable and biocompatible polymers, liposomes, and virus-like particles. While most nanovaccine candidates have not yet advanced beyond testing in rodent models, a growing number have shown promise for use against cattle infectious diseases. This review will highlight recent advancements in polymeric nanovaccine development and the mechanisms by which nanovaccines may interact with the bovine immune system. We will also discuss the positive implications of nanovaccines use for combating several important viral and bacterial disease syndromes and consider important future directions for nanovaccine development in beef and dairy cattle.

Toxicity and Immunogenicity of a Tardigrade Cytosolic Abundant Heat Soluble Protein in Mice

Tardigrades are microscopic animals well-known for their stress tolerance, including the ability to survive desiccation. This survival requires cytosolic abundant heat soluble (CAHS) proteins. CAHS D protects enzymes from desiccation- and lyophilization-induced inactivation in vitro and has the potential to stabilize protein-based therapeutics, including vaccines. Here, we investigate whether purified recombinant CAHS D causes hemolysis or a toxic or immunogenic response following intraperitoneal injection in mice. CAHS D did not cause hemolysis, and all mice survived the 28-day monitoring period. The mice gained weight normally and developed anti-CAHS D antibodies but did not show upregulation of the inflammatory cytokines interleukin-6 and tumor necrosis factor alpha. In summary, CAHS D is not toxic and does not promote an inflammatory immune response in mice under the conditions used here, suggesting the reasonability of further study for use as stabilizers of protein-based therapeutics.

Cost-effectiveness of inhaled oxytocin for prevention of postpartum haemorrhage: a modelling study applied to two high burden settings

BACKGROUND

Access to oxytocin for prevention of postpartum haemorrhage (PPH) in resource-poor settings is limited by the requirement for a consistent cold chain and for a skilled attendant to administer the injection. To overcome these barriers, heat-stable, non-injectable formulations of oxytocin are under development, including oxytocin for inhalation. This study modelled the cost-effectiveness of an inhaled oxytocin product (IHO) in Bangladesh and Ethiopia.

METHODS

A decision analytic model was developed to assess the cost-effectiveness of IHO for the prevention of PPH compared to the standard of care in Bangladesh and Ethiopia. In Bangladesh, introduction of IHO was modelled in all public facilities and home deliveries with or without a skilled attendant. In Ethiopia, IHO was modelled in all public facilities and home deliveries with health extension workers. Costs (costs of introduction, PPH prevention and PPH treatment) and effects (PPH cases averted, deaths averted) were modelled over a 12-month program. Life years gained were modelled over a lifetime horizon (discounted at 3%). Cost of maintaining the cold chain or effects of compromised oxytocin quality (in the absence of a cold chain) were not modelled.

RESULTS

In Bangladesh, IHO was estimated to avert 18,644 cases of PPH, 76 maternal deaths and 1954 maternal life years lost. This also yielded a cost-saving, with the majority of gains occurring among home deliveries where IHO would replace misoprostol. In Ethiopia, IHO averted 3111 PPH cases, 30 maternal deaths and 767 maternal life years lost. The full IHO introduction program bears an incremental cost-effectiveness ratio (ICER) of between 2 and 3 times the per-capita Gross Domestic Product (GDP) ($1880 USD per maternal life year lost) and thus is unlikely to be considered cost-effective in Ethiopia. However, the ICER of routine IHO administration considering recurring cost alone falls under 25% of per-capita GDP ($175 USD per maternal life-year saved).

CONCLUSIONS

IHO has the potential to expand access to uterotonics and reduce PPH-associated morbidity and mortality in high burden settings. This can facilitate reduced spending on PPH management, making the product highly cost-effective in settings where coverage of institutional delivery is lagging.

Creeping Through the Backdoor: Disruption in Medicine and Health

Can disruption happen when no one notices? Disruptive technologies and processes are fundamentally starting to up-end how medicines and health systems benefit patients but the question is whether health systems are ready for them. This paper will briefly review the business strategy and management literature on topics such as disruption and “black swan” theories of change, before turning to discuss some of the areas where change is affecting medicine and healthcare. Such areas include the emergence of cell and gene therapies, the economics of cures, digital technologies, mobile apps, social media, supply chain technologies such as drones and online distribution, universal health coverage and funding, and consumerisation of healthcare. The question to be asked is whether these sorts of changes are “disruptive” or whether they were coming for a long time and it is just that health systems are slow to change. It could be argued that while perhaps unexpected by day-to-day practitioners in healthcare, in fact, many of the changes now starting to affect the health and medicines sector have been affecting other sectors such as technology, finance and communications for decades.

The thermostability of the RTS,S/AS01 malaria vaccine can be increased by co-lyophilizing RTS,S and AS01

Background

Developing thermostable vaccines is a challenge for pharmaceutical companies due to the inherent instability of biological molecules in aqueous solution. The problem is even more stringent in regions subjected to high temperatures in which protective cold chain is difficult to maintain due to a lack of infrastructure. Here, a simple, cost-effective solution to increase the thermostability of the malaria candidate vaccine RTS,S/AS01 is described. This vaccine currently needs to be stored between 2 and 8  °C due to the sensitivity of liquid AS01 to higher temperatures. The strategy was to increase thermostability by co-lyophilizing the RTS,S antigen and AS01.

Methods

Co-lyophilization was achieved in a solution containing 5% sucrose, 10 mM potassium phosphate and 0.0312% polysorbate 80 at pH 6.1. The physicho-chemical characteristics and immunogenic properties of the resulting solid product, called CL-vac, fresh or stored at high temperature, were compared to those of the candidate RTS,S/AS01.

Results

CL-vac proved to be acceptable in terms of visual appearance and physico-chemical characteristics. The structural integrity of both RTS,S and AS01 within CL-vac and its equivalence to the RTS,S/AS01 candidate vaccine were shown. Further, the stability of CL-vac was demonstrated for storage periods including 1 year at 4  °C, 1 year at 30  °C, and up to 6 months at 37  °C. In addition, CL-vac could withstand a heat excursion consisting of 1 month at 45  °C after storage for 1 year at 30  °C. Equivalence and stability were demonstrated by the various analytical tools and the immunogenicity of the samples after storage was also demonstrated in mice.

Conclusions

In conclusion, the co-lyophilization process appeared as a promising approach to increase RTS/AS01 vaccine thermostability.

New GMP manufacturing processes to obtain thermostable HIV-1 gp41 virosomes under solid forms for various mucosal vaccination routes

The main objective of the MACIVIVA European consortium was to develop new Good Manufacturing Practice pilot lines for manufacturing thermostable vaccines with stabilized antigens on influenza virosomes as enveloped virus-like particles. The HIV-1 gp41-derived antigens anchored in the virosome membrane, along with the adjuvant 3M-052 (TLR7/8 agonist) on the same particle, served as a candidate vaccine for the proof of concept for establishing manufacturing processes, which can be directly applied or adapted to other virosomal vaccines or lipid-based particles. Heat spray-dried powders suitable for nasal or oral delivery, and freeze-dried sublingual tablets were successfully developed as solid dosage forms for mucosal vaccination. The antigenic properties of vaccinal antigens with key gp41 epitopes were maintained, preserving the original immunogenicity of the starting liquid form, and also when solid forms were exposed to high temperature (40 °C) for up to 3 months, with minimal antigen and adjuvant content variation. Virosomes reconstituted from the powder forms remained as free particles with similar size, virosome uptake by antigen-presenting cells in vitro was comparable to virosomes from the liquid form, and the presence of excipients specific to each solid form did not prevent virosome transport to the draining lymph nodes of immunized mice. Virosome integrity was also preserved during exposure to <−15 °C, mimicking accidental freezing conditions. These “ready to use and all-in-one” thermostable needle-free virosomal HIV-1 mucosal vaccines offer the advantage of simplified logistics with a lower dependence on the cold chain during shipments and distribution.

Health economic evaluation of current vaccination strategies and new vaccines against tuberculosis: a systematic review

Introduction: Bacillus Calmette-Guérin (BCG) is the only licensed vaccine for tuberculosis, but its effectiveness is limited and varies by age. New candidate vaccines are currently being investigated. In response to the declining incidence of TB, practices relating to BCG vaccination have changed in various countries in recent years. A valid cost-effectiveness study is therefore needed in order to assist decision-makers in the implementation of cost-effective strategies for BCG vaccination. Areas covered: Studies involving economic evaluations of BCG vaccination were reviewed in order to present current findings concerning a range of BCG vaccination strategies in a variety of regions, target populations, and vaccine types. The Quality of Health Economic Studies (QHES) instrument was used to assess the quality of the studies included in the analysis. Expert opinion: Most of the studies showed a favorable economic profile of BCG vaccination. Selective strategies seem the most cost-effective option for low-incidence areas. Varying results on revaccination strategies did not lead to any conclusive finding on the cost-effectiveness of the strategies. A novel vaccine - either a BCG replacement or booster vaccine that provides better protection, especially in adults - has the potential to enhance the cost-effectiveness of vaccinating against tuberculosis.

The value of tailoring vial sizes to populations and locations

BACKGROUND

Frequently, a country will procure a single vaccine vial size, but the question remains whether tailoring the use of different size vaccine vial presentations based on populations or location characteristics within a single country could provide additional benefits, such as reducing open vial wastage (OVW) or reducing missed vaccination opportunities.

METHODS

Using the Highly Extensible Resource for Modeling Supply Chains (HERMES) software, we built a simulation model of the Zambia routine vaccine supply chain. At baseline, we distributed 10-dose Measles-Rubella (MR) vials to all locations, and then distributed 5-dose and 1-dose MR vials to (1) all locations, (2) rural districts, (3) rural health facilities, (4) outreach sites, and (5) locations with average MR session sizes <5 and <10 children. We ran sensitivity on each scenario using MR vial opening thresholds of 0% and 50%, i.e. a healthcare worker opens an MR vaccine for any number of children (0%) or if at least half will be used (50%).

RESULTS

Replacing 10-dose MR with 5-dose MR vials everywhere led to the largest reduction in MR OVW, saving 573,892 doses (103,161 doses with the 50% vial opening threshold) and improving MR availability by 1% (9%). This scenario, however, increased cold chain utilization and led to a 1% decrease in availability of other vaccines. Tailoring 5-dose MR vials to rural health facilities or based on average session size reduced cold transport constraints, increased total vaccine availability (+1%) and reduced total cost per dose administered (-$0.01) compared to baseline.

CONCLUSIONS

In Zambia, tailoring 5-dose MR vials to rural health facilities or by average session size results in the highest total vaccine availability compared to all other scenarios (regardless of OVT policy) by reducing open vial wastage without increasing cold chain utilization.

The potential effects of introducing microneedle patch vaccines into routine vaccine supply chains

BACKGROUND

Microneedle patch (MNP) technology is designed to simplify the process of vaccine administration; however, depending on its characteristics, MNP technology may provide additional benefits beyond the point-of-use, particularly for vaccine supply chains.

METHODS

Using the HERMES modeling software, we examined replacing four routine vaccines - Measles-containing vaccine (MCV), Tetanus toxoid (TT), Rotavirus (Rota) and Pentavalent (Penta) - with MNP versions in the routine vaccine supply chains of Benin, Bihar (India), and Mozambique.

RESULTS

Replacing MCV with an MNP (5 cm³-per-dose, 2-month thermostability, current single-dose price-per-dose) improved MCV availability by 13%, 1% and 6% in Benin, Bihar and Mozambique, respectively, and total vaccine availability by 1% in Benin and Mozambique, while increasing the total cost per dose administered by $0.07 in Benin, $0.56 in Bihar and $0.11 in Mozambique. Replacing TT with an MNP improved TT and total vaccine availability (3% and <1%) in Mozambique only, when the patch was 5 cm³ and 2-months thermostable but increased total cost per dose administered by $0.14. Replacing Rota with an MNP (at 5-15 cm³-per-dose, 1-2 month thermostable) improved Rota and total vaccine availability, but only improved Rota vaccine availability in Bihar (at 5 cm³, 1-2 months thermostable), while decreasing total vaccine availability by 1%. Finally, replacing Penta with an MNP (at 5 cm³, 2-months thermostable) improved Penta vaccine availability by 1-8% and total availability by <1-9%.

CONCLUSIONS

An MNP for MCV, TT, Rota, or Penta would need to have a smaller or equal volume-per-dose than existing vaccine formulations and be able to be stored outside the cold chain for a continuous period of at least two months to provide additional benefits to all three supply chains under modeled conditions.

Dual-chamber injection device for measles-rubella vaccine: The potential impact of introducing varying sizes of the devices in 3 countries

Introduction

By pairing diluent with vaccines, dual-chamber vaccine injection devices simplify the process of reconstituting vaccines before administration and thus decrease associated open vial wastage and adverse events. However, since these devices are larger than current vaccine vials for lyophilized vaccines, manufacturers need guidance as to how the size of these devices may affect vaccine distribution and delivery.

Methods

Using HERMES-generated immunization supply chain models of Benin, Bihar (India), and Mozambique, we replace the routine 10-dose measles-rubella (MR) lyophilized vaccine with single-dose MR dual-chamber injection devices, ranging the volume-per-dose (5.2–26 cm³) and price-per-dose ($0.70, $1.40).

Results

At a volume-per-dose of 5.2 cm³, a dual-chamber injection device results in similar vaccine availability, decreased open vial wastage (OVW), and similar total cost per dose administered as compared to baseline in moderately constrained supply chains. Between volumes of 7.5 cm³ and 26 cm³, these devices lead to a reduction in vaccine availability between 1% and 14% due to increases in cold chain storage utilization between 1% and 7% and increases in average peak transport utilization between 2% and 44%. At the highest volume-per-dose, 26 cm³, vaccine availability decreases between 9% and 14%. The total costs per dose administered varied between each scenario, as decreases in vaccine procurement costs were coupled with decreases in doses administered. However, introduction of a dual-chamber injection device only resulted in improved total cost per dose administered for Benin and Mozambique (at 5.2 cm³ and $0.70-per-dose) when the total number of doses administered changed <1% from baseline.

Conclusion

In 3 different country supply chains, a single-dose MR dual-chamber injection device would need to be no larger than 5.2 cm³ to not significantly impair the flow of other vaccines.

New Routes and Opportunities for Modular Construction of Particulate Vaccines: Stick, Click, and Glue

Vaccines based on virus-like particles (VLPs) can induce potent B cell responses. Some non-chimeric VLP-based vaccines are highly successful licensed products (e.g., hepatitis B surface antigen VLPs as a hepatitis B virus vaccine). Chimeric VLPs are designed to take advantage of the VLP framework by decorating the VLP with a different antigen. Despite decades of effort, there have been few licensed chimeric VLP vaccines. Classic approaches to create chimeric VLPs are either genetic fusion or chemical conjugation, using cross-linkers from lysine on the VLP to cysteine on the antigen. We describe the principles that make these classic approaches challenging, in particular for complex, full-length antigens bearing multiple post-translational modifications. We then review recent advances in conjugation approaches for protein-based non-enveloped VLPs or nanoparticles, to overcome such challenges. This includes the use of strong non-covalent assembly methods (stick), unnatural amino acids for bio-orthogonal chemistry (click), and spontaneous isopeptide bond formation by SpyTag/SpyCatcher (glue). Existing applications of these methods are outlined and we critically consider the key practical issues, with particular insight on Tag/Catcher plug-and-display decoration. Finally, we highlight the potential for modular particle decoration to accelerate vaccine generation and prepare for pandemic threats in human and veterinary realms.

Room Temperature Stable PspA-Based Nanovaccine Induces Protective Immunity

Streptococcus pneumoniae is a major causative agent of pneumonia, a debilitating disease particularly in young and elderly populations, and is the leading worldwide cause of death in children under the age of five. While there are existing vaccines against S. pneumoniae, none are protective across all serotypes. Pneumococcal surface protein A (PspA), a key virulence factor of S. pneumoniae, is an antigen that may be incorporated into future vaccines to address the immunological challenges presented by the diversity of capsular antigens. PspA has been shown to be immunogenic and capable of initiating a humoral immune response that is reactive across approximately 94% of pneumococcal strains. Biodegradable polyanhydrides have been studied as a nanoparticle-based vaccine (i.e., nanovaccine) platform to stabilize labile proteins, to provide adjuvanticity, and enhance patient compliance by providing protective immunity in a single dose. In this study, we designed a room temperature stable PspA-based polyanhydride nanovaccine that eliminated the need for a free protein component (i.e., 100% encapsulated within the nanoparticles). Mice were immunized once with the lead nanovaccine and upon challenge, presented significantly higher survival rates than animals immunized with soluble protein alone, even with a 25-fold reduction in protein dose. This lead nanovaccine formulation performed similarly to protein adjuvanted with Alum, however, with much less tissue reactogenicity at the site of immunization. By eliminating the free PspA from the nanovaccine formulation, the lead nanovaccine was efficacious after being stored dry for 60 days at room temperature, breaking the need for maintaining the cold chain. Altogether, this study demonstrated that a single dose PspA-based nanovaccine against S. pneumoniae induced protective immunity and provided thermal stability when stored at room temperature for at least 60 days.

The importance of vaccine supply chains to everyone in the vaccine world

While the focus of many in the vaccine world has been on developing new vaccines and measuring their effects on humans, failure to understand and properly address vaccine supply chain issues can greatly reduce the impact of any vaccine. Therefore, everyone involved in vaccine decision-making may want to take into account supply chains when making key decisions. In fact, considering supply chain issues long before a vaccine reaches the market can help design vaccines and vaccine programs that better match the system. We detail how vaccine supply chains may affect the work and decision making of ten examples of different members of the vaccine community: preclinical vaccinologists, vaccine clinical trialists, vaccine package designers, health care workers, epidemiologists and disease surveillance experts, policy makers, storage equipment manufacturers, other technology developers, information system specialists, and funders. We offer ten recommendations to help decision makers better understand and address supply chains.