Stability Modelling of mRNA Vaccine Quality Based on Temperature Monitoring throughout the Distribution Chain

Overcoming barriers to medical countermeasures: Strengthening global biosecurity

The COVID-19 pandemic revealed global disparities in accessing medical countermeasures, as high-income countries prioritised their own interests while disregarding low- and middle-income countries. Despite global efforts to ensure an equitable pandemic response, these initiatives largely failed to achieve their objectives for LMICs due to systemic inequalities. This review critically examines these disparities, identifying that excessive stockpiling by HICs, fragmented international coordination, inadequate research and manufacturing capacity, restricted access to emergency research funding, intellectual property constraints, unequal participation in clinical trials, and inadequate regulatory harmonisation collectively hinder LMICs ability to respond effectively. By analysing diverse case scenarios and global response strategies, all plausible key shortcomings that contributed to the failure of coordinated pandemic preparedness were highlighted. Based on these insights, actionable strategies are proposed to address these gaps in LMICs so as to ensure affordability, accessibility, and equitable distribution of vaccines, diagnostics, and biotherapeutics in future public health emergencies, strengthening global biosecurity.

Influence of salt solution on the physicochemical properties and in vitro/ in vivo expression of mRNA/LNP

Lipid nanoparticles (LNPs) have revolutionized nucleic acid delivery, enabling significant advances in mRNA-based therapeutics. While extensive research has focused on lipid composition, the impact of preparation solutions on LNP performance remains underexplored. This study systematically investigated the effects of pH, salt type, and concentration across key preparation solutions-mRNA aqueous, dilution, exchange, and storage solutions-on the physicochemical properties, stability, and expression efficiency of SM102-based mRNA/LNPs. Findings revealed that the pH of the mRNA aqueous solution was critical, with a pH of 4 optimizing encapsulation efficiency (EE) and cellular expression. The exchange solution's pH significantly influenced biodistribution, particularly liver-specific expression following intravenous and intramuscular administration. Sucrose was identified as essential for freeze-thaw stability, with a 300 mM concentration minimizing aggregation and mRNA leakage. Furthermore, preparation solutions were shown to influence the structural integrity of LNPs, impacting their in vivo and in vitro performance. These insights highlight the importance of preparation conditions in optimizing LNP formulations for clinical applications, offering a foundation for enhanced therapeutic design and delivery.

Revolutionizing mRNA Vaccines Through Innovative Formulation and Delivery Strategies

Modernization of existing methods for the delivery of mRNA is vital in advanced therapeutics. Traditionally, mRNA has faced obstacles of poor stability due to enzymatic degradation. This work examines cutting-edge formulation and emerging techniques for safer delivery of mRNA vaccines. Inspired by the success of lipid nanoparticles (LNP) in delivering mRNA vaccines for COVID-19, a variety of other formulations have been developed to deliver mRNA vaccines for diverse infections. The meritorious features of nanoparticle-based mRNA delivery strategies, including LNP, polymeric, dendrimers, polysaccharide-based, peptide-derived, carbon and metal-based, DNA nanostructures, hybrid, and extracellular vesicles, have been examined. The impact of these delivery platforms on mRNA vaccine delivery efficacy, protection from enzymatic degradation, cellular uptake, controlled release, and immunogenicity has been discussed in detail. Even with significant developments, there are certain limitations to overcome, including toxicity concerns, limited information about immune pathways, the need to maintain a cold chain, and the necessity of optimizing administration methods. Continuous innovation is essential for improving delivery systems for mRNA vaccines. Future research directions have been proposed to address the existing challenges in mRNA delivery and to expand their potential prophylactic and therapeutic application.

Left out in the cold - inequity in infectious disease control due to cold chain disparity

Vaccines and diagnostic tools stand out as among the most influential advancements in public health, credited with averting an estimated 6 million deaths annually and substantially alleviating the burden of infectious disease. Despite this progress, the global imperative to prevent, detect, and combat infectious disease persists. Regrettably, hundreds of thousands of lives are still lost due to inadequate access to vaccines and diagnostics. A critical obstacle in accessibility lies in the requirement of reliable cold chain for their transportation and storage, a resource that remains inadequate in many regions, particularly in the developing world. Various factors, including socio-economic disparities, biological complexities, and manufacturing processes, exert significant influence on the availability and integrity of vaccines and diagnostic materials. This review aims to explore the multifaceted issue of inequality in access to disease control tools, examining the vulnerabilities of vaccines and diagnostics while also investigating recent advancements that offer promising solutions to improve thermal stability.

Investigation of Protein Therapeutics in Frozen Conditions Using DNP MAS NMR: A Study on Pembrolizumab

The success of modern biopharmaceutical products depends on enhancing the stability of protein therapeutics. Freezing and thawing, which are common thermal stresses encountered throughout the lifecycle of drug substances, spanning protein production, formulation design, manufacturing, storage, and shipping, can impact this stability. Understanding the physicochemical and molecular behaviors of components in biological drug products at temperatures relevant to manufacturing and shipping is essential for assessing stability risks and determining appropriate storage conditions. This study focuses on the stability of high-concentration monoclonal antibody (mAb) pembrolizumab, the drug substance of Keytruda (Merck & Co., Inc., Rahway, NJ, United States), and its excipients in a frozen solution. By leveraging dynamic nuclear polarization (DNP), we achieve more than 100-fold signal enhancements in solid-state NMR (ssNMR), enabling efficient low-temperature (LT) analysis of pembrolizumab without isotopic enrichment. Through both ex situ and in situ ssNMR experiments conducted across a temperature range of 297 to 77 K, we provide insights into the stability of crystalline pembrolizumab under frozen conditions. Importantly, utilizing LT magic-angle spinning (MAS) probes allows us to study molecular dynamics in pembrolizumab from room temperature down to liquid nitrogen temperatures (<100 K). Our results demonstrate that valuable insights into protein conformation and dynamics, crystallinity, and the phase transformations of excipients during the freezing of the formulation matrix can be readily obtained for biological drug products. This study underscores the potential of LT-MAS ssNMR and DNP techniques for analyzing protein therapeutics and vaccines in frozen solutions.

Cryoprotectant optimization for enhanced stability and transfection efficiency of pDNA-loaded ionizable lipid nanoparticles

Advances in gene therapy, exemplified by mRNA vaccines against COVID-19, highlight the importance of lipid nanoparticles (LNPs) for nucleic acid delivery despite challenging storage conditions. Substituting mRNA with pDNA in LNPs may enhance stability and efficacy, yet maintaining LNP stability poses challenges, particularly during freeze-drying. Cryoprotectants offer potential to mitigate destabilization, improving LNP properties and in vivo performance. Here, we evaluated the effects of different concentrations of various cryoprotectants on the freeze-drying process of pDNA-loaded LNPs, assessing their physicochemical characteristics and transfection efficiency. Stability was examined under various storage conditions, confirming biological efficacy post-storage. Our results highlight the role of cryoprotectants in optimizing freeze-drying for the extended shelf life of nucleic acid-loaded LNPs. Trehalose emerged as an efficient cryoprotectant, maintaining LNP stability after the freeze-drying process for up to 2 years, with diameters and transfection efficiency comparable to fresh formulations. These findings demonstrate the optimized concentration of cryoprotectants to sustain LNP stability despite freeze-drying and prolonged storage, providing valuable insights for nucleic acid-based therapies.

The Impact of COVID-19 on RNA Therapeutics: A Surge in Lipid Nanoparticles and Alternative Delivery Systems

The COVID-19 pandemic has significantly accelerated progress in RNA-based therapeutics, particularly through the successful development and global rollout of mRNA vaccines. This review delves into the transformative impact of the pandemic on RNA therapeutics, with a strong focus on lipid nanoparticles (LNPs) as a pivotal delivery platform. LNPs have proven to be critical in enhancing the stability, bioavailability, and targeted delivery of mRNA, facilitating the unprecedented success of vaccines like those developed by Pfizer-BioNTech and Moderna. Beyond vaccines, LNP technology is being explored for broader therapeutic applications, including treatments for cancer, rare genetic disorders, and infectious diseases. This review also discusses emerging RNA delivery systems, such as polymeric nanoparticles and viral vectors, which offer alternative strategies to overcome existing challenges related to stability, immune responses, and tissue-specific targeting. Additionally, we examine the pandemic's influence on regulatory processes, including the fast-tracked approvals for RNA therapies, and the surge in research funding that has spurred further innovation in the field. Public acceptance of RNA-based treatments has also grown, laying the groundwork for future developments in personalized medicine. By providing an in-depth analysis of these advancements, this review highlights the long-term impact of COVID-19 on the evolution of RNA therapeutics and the future of precision drug delivery technologies.

Effective Synthesis of mRNA during In Vitro Transcription with Fewer Impurities Produced

The remarkable efficacy of COVID-19 vaccines has established mRNA as a highly promising biomedical technology. However, the adequate application of mRNA therapeutics necessitates additional measures to mitigate the inherent immunogenicity, which is predominantly caused by dsRNA. As a byproduct of the in vitro transcription of mRNA, dsRNA was reported to be originated through several distinct mechanisms, including the extension of 3' loop-back hairpins, the extension of hybridized abortive transcripts, and promoter-independent transcription. The intricate mechanisms involved pose a dilemma as the reduction in dsRNA results in a concomitant decrease in other critical quality attributes of mRNA. Here, we demonstrate that the promoter binding motifs of T7 RNA polymerase directly impact the production of promoter-independent transcription-based dsRNA. Specifically, the G753A mutation significantly reduces the formation of dsRNA byproducts, which can further combine with modified nucleotides to enhance the effectiveness of dsRNA mitigation and with previously reported high-integrity mutation K389A to minimize side effects. Accordingly, the present study reports a cost-effective approach to synthesize high-purity, less immunostimulatory mRNA by using an engineered T7 RNA polymerase mutant.

Stability Preparedness: The Not-So-Cold Case for Innovations in Vaccine Stability Modelling and Product Release

The rapid development of equitably accessible vaccines is paramount in addressing emerging global health challenges. The safety and efficacy of vaccines hinge significantly on their ability to remain stable from manufacturing throughout the supply chain and up to administration. Furthermore, the release of vaccines requires sufficient understanding of the stability profile to allow for expiration dating. In the event of a public health crisis, the time to generate the necessary stability data and the need for rapid product release are in direct opposition. Developing manufacturing platforms with thermostable product formulations for rapid response is therefore key to meeting CEPI's 100 Days Mission goal. This Review aims to highlight the need for stability preparedness through developing thermostable vaccine platforms and exploring innovative stability monitoring strategies that leverage advanced technologies, predictive modelling, and adaptive methodologies. By doing so, we seek to enhance the efficiency and effectiveness of stability assessments, supporting rapid development, regulatory approval, and widespread, equal distribution of vaccines-especially in an outbreak scenario. Finally, enhanced thermostability will allow for simplification across the supply chain, which will reduce the financial burden of vaccination programmes and enhance equitable access.

Synergistic Polymer Blending Informs Efficient Terpolymer Design and Machine Learning Discerns Performance Trends for pDNA Delivery

Cationic polymers offer an alternative to viral vectors in nucleic acid delivery. However, the development of polymer vehicles capable of high transfection efficiency and minimal toxicity has remained elusive, and continued exploration of the vast design space is required. Traditional single polymer syntheses with large monomer bases are very time-intensive, limiting the speed at which new formulations are identified. In this work, we present an experimental method for the quick probing of the design space, utilizing a combinatorial set of 90 polymer blends, derived from 6 statistical copolymers, to deliver pDNA. This workflow facilitated rapid screening of polyplex compositions, successfully tailoring polyplex hydrophobicity, particle size, and payload binding affinity. This workflow identified blended polyplexes with high levels of transfection efficiency and cell viability relative to single copolymer controls and commercial JetPEI, indicating synergistic benefits from copolymer blending. Polyplex composition was coupled with biological outputs to guide the synthesis of single terpolymer vehicles, with high-performing polymers P10 and M20, providing superior transfection of HEK293T cells in serum-free and serum-containing media, respectively. Machine learning coupled with SHapley Additive exPlanations (SHAP) was used to identify polymer/polyplex attributes that most impact transfection efficiency, viability, and overall effective efficiency. Subsequent transfections on ARPE-19 and HDFn cells found that P10 and M20 were surpassed in performance by M10, contrasting with results in HEK293T cells. This cell type dependency reinforced the need to evaluate transfection conditions with multiple cell models to potentially identify moieties more beneficial to delivery in certain tissues. Overall, the workflow employed can be used to expedite the exploration of the polymer design space, bypassing extensive synthesis, and to develop improved polymer delivery vehicles more readily for nucleic acid therapies.

Role of Hydrophobic Modification in Spermine-Based Poly(β-amino ester)s for siRNA Delivery and Their Spray-Dried Powders for Inhalation and Improved Storage

After RNAi was first discovered over 20 years ago, siRNA-based therapeutics are finally becoming reality. However, the delivery of siRNA has remained a challenge. In our previous research, we found that spermine-based poly(β-amino ester)s are very promising for siRNA delivery. However, the role of hydrophobic modification in siRNA delivery of spermine-based poly(β-amino ester)s is not fully understood yet. In the current work, we synthesized spermine-based poly(β-amino ester)s with different percentages of oleylamine side chains, named P(SpOABAE). The chemical structures of the polymers were characterized by 1H NMR. The polymers showed efficient siRNA encapsulation determined by SYBR Gold assays. The hydrodynamic diameters of the P(SpOABAE) polyplexes from charge ratio N/P 1 to 20 were 30-100 nm except for aggregation phenomena observed at N/P 3. Morphology of the polyplexes was visualized by atomic force microscopy, and cellular uptake was determined by flow cytometry in H1299 cells, where all the polyplexes showed significantly higher cellular uptake than hyperbranched polyethylenimine (25 kDa). The most hydrophobic P(SpOABAE) polyplexes were able to achieve more than 90% GFP knockdown in H1299/eGFP cells. The fact that gene silencing efficacy increased with hydrophobicity but cellular uptake was affected by both charge and hydrophobic interactions highlights the importance of endosomal escape. For pulmonary administration and improved storage stability, the polyplexes were spray-dried. Results confirmed the maintained siRNA activity after storage for 3 months at room temperature, indicating potential for dry powder inhalation.

Development of Robust Freeze-Drying Process for Long-Term Stability of rVSV-SARS-CoV-2 Vaccine

The thermostability of vaccines, particularly enveloped viral vectored vaccines, remains a challenge to their delivery wherever needed. The freeze-drying of viral vectored vaccines is a promising approach but remains challenging due to the water removal process from the outer and inner parts of the virus. In the case of enveloped viruses, freeze-drying induces increased stress on the envelope, which often leads to the inactivation of the virus. In this study, we designed a method to freeze-dry a recombinant vesicular stomatitis virus (VSV) expressing the SARS-CoV-2 spike glycoprotein. Since the envelope of VSV is composed of 50% lipids and 50% protein, the formulation study focused on both the protein and lipid portions of the vector. Formulations were prepared primarily using sucrose, trehalose, and sorbitol as cryoprotectants; mannitol as a lyoprotectant; and histidine as a buffer. Initially, the infectivity of rVSV-SARS-CoV-2 and the cake stability were investigated at different final moisture content levels. High recovery of the infectious viral titer (~0.5 to 1 log loss) was found at 3-6% moisture content, with no deterioration in the freeze-dried cakes. To further minimize infectious viral titer loss, the composition and concentration of the excipients were studied. An increase from 5 to 10% in both the cryoprotectants and lyoprotectant, together with the addition of 0.5% gelatin, resulted in the improved recovery of the infectious virus titer and stable cake formation. Moreover, the secondary drying temperature of the freeze-drying process showed a significant impact on the infectivity of rVSV-SARS-CoV-2. The infectivity of the vector declined drastically when the temperature was raised above 20 °C. Throughout a long-term stability study, formulations containing 10% sugar (sucrose/trehalose), 10% mannitol, 0.5% gelatin, and 10 mM histidine showed satisfactory stability for six months at 2-8 °C. The development of this freeze-drying process and the optimized formulation minimize the need for a costly cold chain distribution system.

Effective Synthesis of High-Integrity mRNA Using In Vitro Transcription

mRNA vaccines are entering a period of rapid development. However, their synthesis is still plagued by challenges related to mRNA impurities and fragments (incomplete mRNA). Most impurities of mRNA products transcribed in vitro are mRNA fragments. Only full-length mRNA transcripts containing both a 5'-cap and a 3'-poly(A) structure are viable for in vivo expression. Therefore, RNA fragments are the primary product-related impurities that significantly hinder mRNA efficacy and must be effectively controlled; these species are believed to originate from either mRNA hydrolysis or premature transcriptional termination. In the manufacturing of commercial mRNA vaccines, T7 RNA polymerase-catalyzed in vitro transcription (IVT) synthesis is a well-established method for synthesizing long RNA transcripts. This study identified a pivotal domain on the T7 RNA polymerase that is associated with erroneous mRNA release. By leveraging the advantageous properties of a T7 RNA polymerase mutant and precisely optimized IVT process parameters, we successfully achieved an mRNA integrity exceeding 91%, thereby further unlocking the immense potential of mRNA therapeutics.

Unraveling the Multifaceted Roles of Extracellular Vesicles: Insights into Biology, Pharmacology, and Pharmaceutical Applications for Drug Delivery

Extracellular vesicles (EVs) are nanoparticles released from various cell types that have emerged as powerful new therapeutic option for a variety of diseases. EVs are involved in the transmission of biological signals between cells and in the regulation of a variety of biological processes, highlighting them as potential novel targets/platforms for therapeutics intervention and/or delivery. Therefore, it is necessary to investigate new aspects of EVs' biogenesis, biodistribution, metabolism, and excretion as well as safety/compatibility of both unmodified and engineered EVs upon administration in different pharmaceutical dosage forms and delivery systems. In this review, we summarize the current knowledge of essential physiological and pathological roles of EVs in different organs and organ systems. We provide an overview regarding application of EVs as therapeutic targets, therapeutics, and drug delivery platforms. We also explore various approaches implemented over the years to improve the dosage of specific EV products for different administration routes.

Investigations into mRNA Lipid Nanoparticles Shelf-Life Stability under Nonfrozen Conditions

mRNA LNPs can experience a decline in activity over short periods (ranging from weeks to months). As a result, they require frozen storage and transportation conditions to maintain their full functionality when utilized. Currently approved commercially available mRNA LNP vaccines also necessitate frozen storage and supply chain management. Overcoming this significant inconvenience in the future is crucial to reducing unnecessary costs and challenges associated with storage and transport. In this study, our objective was to illuminate the potential time frame for nonfrozen storage and transportation conditions of mRNA LNPs without compromising their activity. To achieve this goal, we conducted a stability assessment and an in vitro cell culture delivery study involving five mRNA LNPs. These LNPs were constructed by using a standard formulation similar to that employed in the three commercially available LNP formulations. Among these formulations, we selected five structurally diverse ionizable lipids─C12-200, CKK-E12, MC3, SM-102, and lipid 23─from the existing literature. We incorporated these lipids into a standard LNP formulation, keeping all other components identical. The LNPs, carrying mRNA payloads, were synthesized by using microfluidic mixing technology. We evaluated the shelf life stability of these LNPs over a span of 9 weeks at temperatures of 2-8, 25, and 40 °C, utilizing an array of analytical techniques. Our findings indicated minimal impact on the hydrodynamic diameter, zeta potential, encapsulation efficiency, and polydispersity of all LNPs across the various temperatures over the studied period. The RiboGreen assay analysis of LNPs showed consistent mRNA contents over several weeks at various nonfrozen storage temperatures, leading to the incorrect assumption of intact and functional LNPs. This misunderstanding was rectified by the significant differences observed in EGFP protein expression in an in vitro cell culture (using HEK293 cells) across the five LNPs. Specifically, only LNP 1 (C12-200) and LNP 4 (SM-102) exhibited high levels of EGFP expression at the start (T0), with over 90% of HEK293 cells transfected and mean fluorescence intensity (MFI) levels exceeding 1. Interestingly, LNP 1 (C12-200) maintained largely unchanged levels of in vitro activity over 11 weeks when stored at both 2-8 and 25 °C. In contrast, LNP 4 (SM-102) retained its functionality when stored at 2-8 °C over 11 weeks but experienced a gradual decline of in vitro activity when stored at room temperature over the same period. Importantly, we observed distinct LNP architectures for the five formulations through cryo-EM imaging. This highlights the necessity for a deeper comprehension of structure-activity relationships within these complex nanoparticle structures. Enhancing our understanding in this regard is vital for overcoming storage and stability limitations, ultimately facilitating the broader application of this technology beyond vaccines.

Association of Type of Vaccination Center With Time to Emergency Department Presentation for Acute COVID-19 Infection: An Exploratory Analysis

Objective The objective of this study was to identify potential associations between coronavirus disease 2019 (COVID-19) vaccination center reception location and time to presentation to the emergency department for acute COVID-19 infection. The a priori hypothesis was that there are significant differences in the outcome based on vaccination administration center type. Methods This was a cross-sectional, observational study conducted within a hospital in Lakeland, Florida, between October 2021 and May 2022. Participants were at least 18 years old with confirmed severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) infection and at least two COVID-19 symptoms at enrollment. Patients with prior confirmed COVID-19 diagnosis and hospitalization within 10 days of screening were excluded. Participants were sampled from within the emergency department of the institution. The primary outcome was time to presentation to the emergency department for acute COVID-19 infection since the last vaccination dose from each sampled COVID-19 vaccination center location. Results A total of 93 participants were analyzed. Of these, 48 (52%) participants received COVID-19 vaccination. Participants vaccinated at vaccine clinics demonstrated a significantly longer mean survival time (288.2 (29.9)) compared to other sites. Significant predictors of hospitalization were age (aOR, 1.09, 95%CI 1.02-1.16, p < 0.01), sex (aOR: 10.05, 95%CI 1.52-66.54, p < 0.05), physical function (aOR, 0.90, 95%CI 0.83-0.97, p < 0.01) and number of medications (aOR, 1.34, 95%CI 1.14-1.58, p < 0.001).  Conclusions This exploratory analysis highlights the need for further investigation into both characteristics of healthcare institutions and individual-level factors that may play a role in the prolonged prevention of emergency department presentations due to COVID-19 infection. Increased transparency of data regarding practices related to the administration of COVID-19 vaccines across various institutions may be beneficial in further understanding the role of COVID-19 vaccinations in preventing symptomatic disease across local and global communities.

Evaluation of the effects of storage conditions on spray-dried siRNA-LNPs before and after subsequent drying

In an ideal world, pharmaceutical drugs would have infinite shelf life, no susceptibility to degradation, chemical reactions or loss of efficacy. In reality, these processes occur, however, making it desirable to extend a drugs' shelf life. Nucleic acid-based drugs are most commonly stored as aqueous suspension where they are vulnerable to microbial growth and degradation processes. Drying procedures, such as lyophilization and spray drying, help to reduce the products' residual moisture while increasing the products' shelf life and stability. The present study was designed to evaluate 90 days of storage of spray-dried siRNA-lipid nanoparticles (LNPs) at 4 °C and 25 °C. An updated Onpattro® composition modified with a positively charged helper lipid was used as the LNP carrier system. In an attempt to further reduce the residual moisture of our previously reported formulations, all LNP samples were subjected to a secondary drying step in the spray drying tower for 20 min. The measurement of physicochemical properties of spray-dried and subsequently dried LNPs resulted in sizes of 180 nm, PDI values of 0.1-0.15 and zeta potentials of + 3 mV. Spray drying resulted in residual moisture levels of 3.6-4 % and was reduced by subsequent drying to 2.8-3.1 %. Aerodynamic properties after storage showed discrepancies depending on the storage conditions. MMADs remained at 2.8 µm when stored at 4 °C, whereas an increase to 5 µm at 25 °C was observed. Subsequent drying led to sizes of 3.6-3.8 µm, independent of the storage conditions. Spray-dried LNPs maintained bioactivity resulting in > 95 % protein downregulation and confirming the lack of cytotoxic effects in a lung adenocarcinoma cell line. Furthermore, the spray-dried and subsequently dried LNPs stored for 3 months at 4 °C and 25 °C achieved up to 50 % gene silencing of the house-keeping gene GAPDH after deposition on the mucus layer of Calu-3 cells. This study confirms the stability of spray-dried and subsequently dried LNPs over at least 90 days at 4 °C and 25 °C emphasizing the potential of dry powder inhalation of RNA-loaded LNPs as a therapy option for pulmonary diseases.

Intradermal administration of DNA vaccine targeting Omicron SARS-CoV-2 via pyro-drive jet injector provides the prolonged neutralizing antibody production via germinal center reaction

Emerging SARS-CoV-2 Omicron variants are highly contagious with enhanced immune escape mechanisms against the initially approved COVID-19 vaccines. Therefore, we require stable alternative-platform vaccines that confer protection against newer variants of SARS-CoV-2. We designed an Omicron B.1.1.529 specific DNA vaccine using our DNA vaccine platform and evaluated the humoral and cellular immune responses. SD rats intradermally administered with Omicron-specific DNA vaccine via pyro-drive jet injector (PJI) thrice at 2-week intervals elicited high antibody titers against the Omicron subvariants as well as the ancestral strain. Indeed, the Omicron B.1.1.529-specific antibody titer and neutralizing antibody were higher than that of other strains. Longitudinal monitoring indicated that anti-spike (ancestral and Omicron) antibody titers decreased toward 30 weeks after the first vaccination dose. However, neutralization activity remained unaltered. Germinal center formation was histologically detected in lymph nodes in rats immunized with Omicron DNA vaccine. Ancestral spike-specific immune cell response was slightly weaker than Omicron spike-specific response in splenocytes with Omicron-adapted DNA vaccine, evaluated by ELISpot assay. Collectively, our findings suggest that Omicron targeting DNA vaccines via PJI can elicit robust durable antibody production mediated by germinal center reaction against this new variant as well as partially against the spike protein of other SARS-CoV-2 variants.

A universal tool for stability predictions of biotherapeutics, vaccines and in vitro diagnostic products

It is of particular interest for biopharmaceutical companies developing and distributing fragile biomolecules to warrant the stability and activity of their products during long-term storage and shipment. In accordance with quality by design principles, advanced kinetic modeling (AKM) has been successfully used to predict long-term product shelf-life and relies on data from short-term accelerated stability studies that are used to generate Arrhenius-based kinetic models that can, in turn, be exploited for stability forecasts. The AKM methodology was evaluated through a cross-company perspective on stability modeling for key stability indicating attributes of different types of biotherapeutics, vaccines and biomolecules combined in in vitro diagnostic kits. It is demonstrated that stability predictions up to 3 years for products maintained under recommended storage conditions (2-8 °C) or for products that have experienced temperature excursions outside the cold-chain show excellent agreement with experimental real-time data, thus confirming AKM as a universal and reliable tool for stability predictions for a wide range of product types.

A Cost-Benefit Analysis Simulation for the Digitalisation of Cold Supply Chains

This paper investigates using simulation to predict the benefits and costs of digitalising cold distribution chains. The study focuses on the distribution of refrigerated beef in the UK, where digitalisation was implemented to re-route cargo carriers. By comparing simulations of both digitalised and non-digitalised supply chains, the study found that digitalisation can reduce beef waste and decrease the number of miles driven per successful delivery, leading to potential cost savings. Note that this work is not attempting to prove that digitalisation is appropriate for the chosen scenario, only to justify a simulation approach as a decision making tool. The proposed modelling approach provides decision-makers with more accurate predictions of the cost-benefit of increased sensorisation in supply chains. By accounting for stochastic and variable parameters, such as weather and demand fluctuations, simulation can be used to identify potential challenges and estimate the economic benefits of digitalisation. Moreover, qualitative assessments of the impact on customer satisfaction and product quality can help decision-makers consider the broader impacts of digitalisation. Overall, the study suggests that simulation can play a crucial role in facilitating informed decisions about the implementation of digital technologies in the food supply chain. By providing a better understanding of the potential costs and benefits of digitalisation, simulation can help organisations make more strategic and effective decisions.

Vaccines on demand, part II: future reality

INTRODUCTION

Prior to the emergence of SARS-CoV-2, the potential use of mRNA vaccines for a rapid pandemic response had been well described in the scientific literature, however during the SARS-CoV-2 outbreak we witnessed the large-scale deployment of the platform in a real pandemic setting. Of the three RNA platforms evaluated in clinical trials, including 1) conventional, non-amplifying mRNA (mRNA), 2) base-modified, non-amplifying mRNA (bmRNA), which incorporate chemically modified nucleotides, and 3) self-amplifying RNA (saRNA), the bmRNA technology emerged with superior clinical efficacy.

AREAS COVERED

This review describes the current state of these mRNA vaccine technologies, evaluates their strengths and limitations, and argues that saRNA may have significant advantages if the limitations of stability and complexities of manufacturing can be overcome.

EXPERT OPINION

The success of the SARS-CoV-2 mRNA vaccines has been remarkable. However, several challenges remain to be addressed before this technology can successfully be applied broadly to other disease targets. Innovation in the areas of mRNA engineering, novel delivery systems, antigen design, and high-quality manufacturing will be required to achieve the full potential of this disruptive technology.

Modified DNA vaccine confers improved humoral immune response and effective virus protection against SARS-CoV-2 delta variant

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global pandemic. New technologies have been utilized to develop several types of vaccines to prevent the spread of SARS-CoV-2 infection, including mRNA vaccines. Our group previously developed an effective DNA-based vaccine. However, emerging SARS-CoV-2 variants of concern (VOCs), such as the delta variant, have escaped mutations against vaccine-induced neutralizing antibodies. This suggests that modified vaccines accommodating VOCs need to be developed promptly. Here, we first modified the current DNA vaccine to enhance antigenicity. Compared with the parental DNA vaccine, the modified version (GP∆-DNA vaccine) induced rapid antibody production. Next, we updated the GP∆-DNA vaccine to spike glycoprotein of the delta variant (GP∆-delta DNA vaccine) and compared the efficacy of different injection routes, namely intramuscular injection using a needle and syringe and intradermal injection using a pyro-drive jet injector (PJI). We found that the levels of neutralizing antibodies induced by the intradermal PJI injection were higher than intramuscular injection. Furthermore, the PJI-injected GP∆-delta DNA vaccine effectively protected human angiotensin-converting enzyme 2 (hACE2) knock-in mice from delta-variant infection. These results indicate that the improved DNA vaccine was effective against emerging VOCs and was a potential DNA vaccine platform for future VOCs or global pandemics.

Stability Study of mRNA-Lipid Nanoparticles Exposed to Various Conditions Based on the Evaluation between Physicochemical Properties and Their Relation with Protein Expression Ability

Lipid nanoparticles (LNPs) are currently in the spotlight as delivery systems for mRNA therapeutics and have been used in the Pfizer/BioNTech and Moderna COVID-19 vaccines. mRNA-LNP formulations have been indicated to require strict control, including maintenance at fairly low temperatures during their transport and storage. Since it is a new pharmaceutical modality, there is a lack of information on the systematic investigation of how storage and handling conditions affect the physicochemical properties of mRNA-LNPs and their protein expression ability. In this study, using the mRNA-LNPs with standard composition, we evaluated the effects of temperature, cryoprotectants, vibration, light exposure, and syringe aspiration from the vials on the physicochemical properties of nanoparticles in relation to their in vitro/in vivo protein expression ability. Among these factors, storage at -80 °C without a cryoprotectant caused a decrease in protein expression, which may be attributed to particle aggregation. Exposure to vibration and light also caused similar changes under certain conditions. Exposure to these factors can occur during laboratory and hospital handling. It is essential to have sufficient knowledge of the stability of mRNA-LNPs in terms of their physical properties and protein expression ability at an early stage to ensure reproducible research and development and medical care.

Design Strategies for and Stability of mRNA-Lipid Nanoparticle COVID-19 Vaccines

Messenger RNA (mRNA) vaccines have shown great preventive potential in response to the novel coronavirus (COVID-19) pandemic. The lipid nanoparticle (LNP), as a non-viral vector with good safety and potency factors, is applied to mRNA delivery in the clinic. Among the recently FDA-approved SARS-CoV-2 mRNA vaccines, lipid-based nanoparticles have been shown to be well-suited to antigen presentation and enhanced immune stimulation to elicit potent humoral and cellular immune responses. However, a design strategy for optimal mRNA-LNP vaccines has not been fully elaborated. In this review, we comprehensively and systematically discuss the research strategies for mRNA-LNP vaccines against COVID-19, including antigen and lipid carrier selection, vaccine preparation, quality control, and stability. Meanwhile, we also discuss the potential development directions for mRNA-LNP vaccines in the future. We also conduct an in-depth review of those technologies and scientific insights in regard to the mRNA-LNP field.

Helper-Polymer Based Five-Element Nanoparticles (FNPs) for Lung-Specific mRNA Delivery with Long-Term Stability after Lyophilization

Lipid nanoparticles (LNPs) carrying therapeutic mRNAs hold great promise in treating lung-associated diseases like viral infections, tumors, and genetic disorders. However, because of their thermodynamically unstable nature, traditional LNPs carrying mRNAs need to be stored at low temperatures, which hinders their prevalence. Herein, an efficient lung-specific mRNA delivery platform named five-element nanoparticles (FNPs) is developed in which helper-polymer poly(β-amino esters) (PBAEs) and DOTAP are used in combination. The new strategy endows FNPs with high stability by increasing the charge repulsion between nanoparticles and the binding force of the aliphatic chains within the nanoparticles. The structure-activity relationship (SAR) shows that PBAEs with E1 end-caps, higher degrees of polymerization, and longer alkyl side chains exhibit higher hit rates. Lyophilized FNP formulations can be stably stored at 4 °C for at least 6 months. Overall, a novel delivery platform with high efficiency, specificity, and stability was developed for advancing mRNA-based therapies for lung-associated diseases.

Keeping up with the COVID's-Could siRNA-based antivirals be a part of the answer?

Coronavirus disease 2019 (COVID-19) is a highly contagious viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This deadly infection has resulted in more than 5.2 million deaths worldwide. The global rollout of COVID-19 vaccines has without doubt saved countless lives by reducing the severity of symptoms for patients. However, as the virus continues to evolve, there is a risk that the vaccines and antiviral designed to target the infection will no longer be therapeutically viable. Furthermore, there remain fears over both the short and long-term side effects of repeat exposure to currently available vaccines. In this review, we discuss the pros and cons of the vaccine rollout and promote the idea of a COVID medicinal toolbox made up of different antiviral treatment modalities, and present some of the latest therapeutic strategies that are being explored in this respect to try to combat the COVID-19 virus and other COVID viruses that are predicted to follow. Lastly, we review current literature on the use of siRNA therapeutics as a way to remain adaptable and in tune with the ever-evolving mutation rate of the COVID-19 virus.

mRNA-based vaccine technology for HIV

Human immunodeficiency virus (HIV) poses a major health problem around the globe, resulting in hundred-thousands of deaths from AIDS and over a million new infections annually. Although the standard treatment of HIV infection, antiretroviral therapy, has proven effective in preventing HIV transmission, it is unsuitable for worldwide use due to its substantial costs and frequent adverse effects. Besides promoting HIV/AIDS awareness through education, there is hardly an alternative for inhibiting the spread of the disease. One promising approach is the development of an HIV vaccine. Unfortunately, the high variability of envelope proteins from HIV subtypes, their frequency of mutation and the lack of fully understanding the mechanisms of protection against the virus constitute an obstacle for vaccine development. Efforts for developing successful anti-HIV vaccines have been underway for decades now, with little success. Lately, significant progress has been made in adopting the novel mRNA vaccine approach as an anti-HIV strategy. mRNA vaccines received a great thrust during the COVID-19 pandemic. Now, several mRNA-based HIV vaccines are undergoing clinical trials to evaluate their safety and efficacy. This review offers an overview of the pathogenesis and treatment of HIV / AIDS, previous efforts of HIV vaccine development and introduces mRNA vaccines as a promising and potential game changing platform for HIV vaccination.