Synthetic Messenger RNA-Based Vaccines: from Scorn to Hype

An engineered T7 RNA polymerase for efficient co-transcriptional capping with reduced dsRNA byproducts in mRNA synthesis

Messenger RNA (mRNA) therapies have recently gained tremendous traction with the approval of mRNA vaccines for the prevention of SARS-CoV-2 infection. However, manufacturing challenges have complicated large scale mRNA production, which is necessary for the clinical viability of these therapies. Not only can the incorporation of the required 5' 7-methylguanosine cap analog be inefficient and costly, in vitro transcription (IVT) using wild-type T7 RNA polymerase generates undesirable double-stranded RNA (dsRNA) byproducts that elicit adverse host immune responses and are difficult to remove at large scale. To overcome these challenges, we have engineered a novel RNA polymerase, T7-68, that co-transcriptionally incorporates both di- and tri-nucleotide cap analogs with high efficiency, even at reduced cap analog concentrations. We also demonstrate that IVT products generated with T7-68 have reduced dsRNA content.

Review: N1-methyl-pseudouridine (m1Ψ): Friend or foe of cancer?

Due to the health emergency created by SARS-CoV-2, the virus that causes the COVID-19 disease, the rapid implementation of a new vaccine technology was necessary. mRNA vaccines, being one of the cutting-edge new technologies, attracted significant interest and offered a lot of hope. The potential of these vaccines in preventing admission to hospitals and serious illness in people with comorbidities has recently been called into question due to the vaccines' rapidly waning immunity. Mounting evidence indicates that these vaccines, like many others, do not generate sterilizing immunity, leaving people vulnerable to recurrent infections. Additionally, it has been discovered that the mRNA vaccines inhibit essential immunological pathways, thus impairing early interferon signaling. Within the framework of COVID-19 vaccination, this inhibition ensures an appropriate spike protein synthesis and a reduced immune activation. Evidence is provided that adding 100 % of N1-methyl-pseudouridine (m1Ψ) to the mRNA vaccine in a melanoma model stimulated cancer growth and metastasis, while non-modified mRNA vaccines induced opposite results, thus suggesting that COVID-19 mRNA vaccines could aid cancer development. Based on this compelling evidence, we suggest that future clinical trials for cancers or infectious diseases should not use mRNA vaccines with a 100 % m1Ψ modification, but rather ones with the lower percentage of m1Ψ modification to avoid immune suppression.

Therapeutic Applications of Nanomedicine: Recent Developments and Future Perspectives

The concept of nanomedicine has evolved significantly in recent decades, leveraging the unique phenomenon known as the enhanced permeability and retention (EPR) effect. This has facilitated major advancements in targeted drug delivery, imaging, and individualized therapy through the integration of nanotechnology principles into medicine. Numerous nanomedicines have been developed and applied for disease treatment, with a particular focus on cancer therapy. Recently, nanomedicine has been utilized in various advanced fields, including diagnosis, vaccines, immunotherapy, gene delivery, and tissue engineering. Multifunctional nanomedicines facilitate concurrent medication delivery, therapeutic monitoring, and imaging, allowing for immediate responses and personalized treatment plans. This review concerns the major advancement of nanomaterials and their potential applications in the biological and medical fields. Along with this, we also mention the various clinical translations of nanomedicine and the major challenges that nanomedicine is currently facing to overcome the clinical translation barrier.

A Review of Clinical Trials of Cancer and Its Treatment as a Vaccine

BACKGROUND

Cancer and infectious diseases are one of the greatest challenges of modern medicine. An unhealthy lifestyle, poor drug use, or drug misuse contribute to the rise in morbidity and mortality brought on by these illnesses. The inadequacies of the medications now being used to treat these disorders, along with the growing issue of drug resistance, have compelled researchers to look for novel compounds with therapeutic promise. The number of infections and diseases has significantly abated due to vaccine development and use over time, which is described in detail. Several novel vaccines can now be produced by manipulating Deoxyribonucleic acid (DNA), Ribonucleic acid (RNA), Messenger Ribonucleic acid (mRNA), proteins, viral vector Recombinant, and other molecules due to advances in genetic engineering and our understanding of the immune defense.

OBJECTIVE

The main topic of discussion is cancer-based vaccinations, which were developed less than a decade ago but have already been used to treat a wide range of both life-threatening and deadly diseases. It contains clinical studies for cancer vaccines against kidney, liver, prostate, cervix, and certain RNA-based cancer vaccines against breast and bladder cancer.

RESULTS

Numerous studies using various DNA and RNA-based methods have been conducted on the basis of cancer, with 9-10 diseases related to DNA and 8-9 diseases associated with RNA. Some of these studies have been completed, while others have been eliminated due to a lack of research; further studies are ongoing regarding the same.

CONCLUSION

This brief discussion of vaccines and their varieties with examples also discusses vaccine clinical trials in relation to cancer diseases in this DNA and RNA-based cancer vaccine that has had successful clinical trials like the cervical cancer drug VGX-3100, the kidney cancer drug Pembrolizumab, MGN-1601, the prostate cancer drug pTVG-HP with rhGM-CSF, the melanoma cancer drug proteasome siRNA, and the lung cancer drug FRAME-001.

Emerging Treatment Approaches for COVID-19 Infection: A Critical Review

In the present scenario, the SARS-CoV-2 virus has imposed enormous damage on human survival and the global financial system. It has been estimated that around 111 million people all around the world have been infected, and about 2.47 million people died due to this pandemic. The major symptoms were sneezing, coughing, cold, difficulty breathing, pneumonia, and multi-organ failure associated 1with SARS-CoV-2. Currently, two key problems, namely insufficient attempts to develop drugs against SARSCoV-2 and the lack of any biological regulating process, are mostly responsible for the havoc caused by this virus. Henceforth, developing a few novel drugs is urgently required to cure this pandemic. It has been noticed that the pathogenesis of COVID-19 is caused by two main events: infection and immune deficiency, that occur during the pathological process. Antiviral medication can treat both the virus and the host cells. Therefore, in the present review, the major approaches for the treatment have been divided into "target virus" and "target host" groups. These two mechanisms primarily rely on drug repositioning, novel approaches, and possible targets. Initially, we discussed the traditional drugs per the physicians' recommendations. Moreover, such therapeutics have no potential to fight against COVID-19. After that, detailed investigation and analysis were conducted to find some novel vaccines and monoclonal antibodies and conduct a few clinical trials to check their effectiveness against SARSCoV- 2 and mutant strains. Additionally, this study presents the most successful methods for its treatment, including combinatorial therapy. Nanotechnology was studied to build efficient nanocarriers to overcome the traditional constraints of antiviral and biological therapies.

Harnessing synthetic biology for advancing RNA therapeutics and vaccine design

Recent global events have drawn into focus the diversity of options for combatting disease across a spectrum of prophylactic and therapeutic approaches. The recent success of the mRNA-based COVID-19 vaccines has paved the way for RNA-based treatments to revolutionize the pharmaceutical industry. However, historical treatment options are continuously updated and reimagined in the context of novel technical developments, such as those facilitated through the application of synthetic biology. When it comes to the development of genetic forms of therapies and vaccines, synthetic biology offers diverse tools and approaches to influence the content, dosage, and breadth of treatment with the prospect of economic advantage provided in time and cost benefits. This can be achieved by utilizing the broad tools within this discipline to enhance the functionality and efficacy of pharmaceutical agent sequences. This review will describe how synthetic biology principles can augment RNA-based treatments through optimizing not only the vaccine antigen, therapeutic construct, therapeutic activity, and delivery vector. The enhancement of RNA vaccine technology through implementing synthetic biology has the potential to shape the next generation of vaccines and therapeutics.

In Vitro Transcribed RNA-Based Platform Vaccines: Past, Present, and Future

mRNA was discovered in 1961, but it was not used as a vaccine until after three decades. Recently, the development of mRNA vaccine technology gained great impetus from the pursuit of vaccines against COVID-19. To improve the properties of RNA vaccines, and primarily their circulation time, self-amplifying mRNA and trans-amplifying mRNA were developed. A separate branch of mRNA technology is circular RNA vaccines, which were developed with the discovery of the possibility of translation on their protein matrix. Circular RNA has several advantages over mRNA vaccines and is considered a fairly promising platform, as is trans-amplifying mRNA. This review presents an overview of the mRNA platform and a critical discussion of the more modern self-amplifying mRNA, trans-amplifying mRNA, and circular RNA platforms created on its basis. Finally, the main features, advantages, and disadvantages of each of the presented mRNA platforms are discussed. This discussion will facilitate the decision-making process in selecting the most appropriate platform for creating RNA vaccines against cancer or viral diseases.

Lipid carriers for mRNA delivery

Messenger RNA (mRNA) is the template for protein biosynthesis and is emerging as an essential active molecule to combat various diseases, including viral infection and cancer. Especially, mRNA-based vaccines, as a new type of vaccine, have played a leading role in fighting against the current global pandemic of COVID-19. However, the inherent drawbacks, including large size, negative charge, and instability, hinder its use as a therapeutic agent. Lipid carriers are distinguishable and promising vehicles for mRNA delivery, owning the capacity to encapsulate and deliver negatively charged drugs to the targeted tissues and release cargoes at the desired time. Here, we first summarized the structure and properties of different lipid carriers, such as liposomes, liposome-like nanoparticles, solid lipid nanoparticles, lipid-polymer hybrid nanoparticles, nanoemulsions, exosomes and lipoprotein particles, and their applications in delivering mRNA. Then, the development of lipid-based formulations as vaccine delivery systems was discussed and highlighted. Recent advancements in the mRNA vaccine of COVID-19 were emphasized. Finally, we described our future vision and perspectives in this field.

STING agonist-boosted mRNA immunization via intelligent design of nanovaccines for enhancing cancer immunotherapy

Messenger RNA (mRNA) vaccine is revolutionizing the methodology of immunization in cancer. However, mRNA immunization is drastically limited by multistage biological barriers including poor lymphatic transport, rapid clearance, catalytic hydrolysis, insufficient cellular entry and endosome entrapment. Herein, we design a mRNA nanovaccine based on intelligent design to overcome these obstacles. Highly efficient nanovaccines are carried out with machine learning techniques from datasets of various nanocarriers, ensuring successful delivery of mRNA antigen and cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) to targets. It activates stimulator of interferon genes (STING), promotes mRNA-encoded antigen presentation and boosts antitumour immunity in vivo, thus inhibiting tumour growth and ensuring long-term survival of tumour-bearing mice. This work provides a feasible and safe strategy to facilitate STING agonist-synergized mRNA immunization, with great translational potential for enhancing cancer immunotherapy.

Anti-CD117 CAR T cells incorporating a safety switch eradicate human acute myeloid leukemia and hematopoietic stem cells

Discrimination between hematopoietic stem cells and leukemic stem cells remains a major challenge for acute myeloid leukemia immunotherapy. CAR T cells specific for the CD117 antigen can deplete malignant and healthy hematopoietic stem cells before consolidation with allogeneic hematopoietic stem cell transplantation in absence of cytotoxic conditioning. Here we exploit non-viral technology to achieve early termination of CAR T cell activity to prevent incoming graft rejection. Transient expression of an anti-CD117 CAR by mRNA conferred T cells the ability to eliminate CD117+ targets in vitro and in vivo. As an alternative approach, we used a Sleeping Beauty transposon vector for the generation of CAR T cells incorporating an inducible Caspase 9 safety switch. Stable CAR expression was associated with high proportion of T memory stem cells, low levels of exhaustion markers, and potent cellular cytotoxicity. Anti-CD117 CAR T cells mediated depletion of leukemic cells and healthy hematopoietic stem cells in NSG mice reconstituted with human leukemia or CD34+ cord blood cells, respectively, and could be terminated in vivo. The use of a non-viral technology to control CAR T cell pharmacokinetic properties is attractive for a first-in-human study in patients with acute myeloid leukemia prior to hematopoietic stem cell transplantation.

Current Status and Trends in Nucleic Acids for Cancer Therapy: A Focus on Polysaccharide-Based Nanomedicines

The efficacious delivery of therapeutic nucleic acids to cancer still remains an open issue. Through the years, several strategies are developed for the encapsulation of genetic molecules exploiting different materials, such as viral vectors, lipid nanoparticles (LNPs), and polymeric nanoparticles (NPs). Indeed, the rapid approval by regulatory authorities and the wide use of LNPs complexing the mRNA coding for the spark protein for COVID-19 vaccination paved the way for the initiation of several clinical trials exploiting lipid nanoparticles for cancer therapy. Nevertheless, polymers still represent a valuable alternative to lipid-based formulations, due to the low cost and the chemical flexibility that allows for the conjugation of targeting ligands. This review will analyze the status of the ongoing clinical trials for cancer therapy, including vaccination and immunotherapy approaches, exploiting polymeric materials. Among those nanosized carriers, sugar-based backbones are an interesting category. A cyclodextrin-based carrier (CALAA-01) is the first polymeric material to enter a clinical trial complexed with siRNA for cancer therapy, and chitosan is one of the most characterized non-viral vectors able to complex genetic material. Finally, the recent advances in the use of sugar-based polymers (oligo- and polysaccharides) for the complexation of nucleic acids in advanced preclinical stage will be discussed.

Short Carbon Nanotube-Based Delivery of mRNA for HIV-1 Vaccines

Developing a safe and effective preventive for HIV-1 remains the hope for controlling the global AIDS epidemic. Recently, mRNA vaccines have emerged as a promising alternative to conventional vaccine approaches, primarily due to their rapid development and potential for low-cost manufacture. Despite the advantages of mRNA vaccines, challenges remain, especially due to the adverse effects of the delivery vehicle and low delivery efficiency. As a result, Luna Labs is developing a short carbon nanotube-based delivery platform (NanoVac) that can co-deliver mRNA and HIV-1 glycoproteins to the immune system efficiently with negligible toxicity. Surface chemistries of NanoVac were optimized to guide antigen/mRNA loading density and presentation. Multiple formulations were engineered for compatibility with both intramuscular and intranasal administration. NanoVac candidates demonstrated immunogenicity in rabbits and generated human-derived humoral and cellular responses in humanized mice (HIS). Briefly, 33% of the HIV-1-infected HIS mice vaccinated with NanoVac-mRNA was cleared of virus infection by 8-weeks post-infection. Finally, NanoVac stabilized the loaded mRNA against degradation under refrigeration for at least three months, reducing the cold chain burden for vaccine deployment.

Nonreplicating synthetic mRNA vaccines: A journey through the European (Journal of Immunology) history

The first worldwide article reporting that injections of synthetic nonreplicating mRNA could be used as a vaccine, which originated from a French team located in Paris, was published in the European Journal of Immunology (EJI) in 1993. It relied on work conducted by several research groups in a handful of countries since the 1960s, which put forward the precise description of eukaryotic mRNA and the method to reproduce this molecule in vitro as well as how to transfect it into mammalian cells. Thereafter, the first industrial development of this technology began in Germany in 2000, with the founding of CureVac, which stemmed from another description of a synthetic mRNA vaccine published in EJI in 2000. The first clinical studies investigating mRNA vaccines in humans were performed as collaboration between CureVac and the University of Tübingen in Germany as early as 2003. Finally, the first worldwide approved mRNA vaccine (an anti-COVID-19 vaccine) is based on the mRNA technologies developed by BioNTech since its 2008 foundation in Mainz, Germany, and earlier by the pioneering academic work of its founders. In addition to the past, present, and future of mRNA-based vaccines, the article aims to present the geographical distribution of the early work, how the development of the technology was implemented by several independent and internationally distributed research teams, as well as the controversies on the optimal way to design or formulate and administer mRNA vaccines.

Utilization of genetic information for medicines development and equitable benefit sharing

Advances in genomic research have significantly enhanced modern drug development. However, equitable benefit sharing of the results of scientific advancement has not always been achieved. This paper shows how molecular biology has modified medicines development while also leaving open significant challenges for benefit sharing. Presented here is a conceptual modeling describing the processes in genetic-related medicines development and how these are related to specific ethical considerations. The focus is on three important areas: 1) population genetics and the need for discrimination prevention; 2) pharmacogenomics and the need for inclusive governance; and 3) global health to be achieved in open science frameworks. Benefit sharing is taken as the ethical value that underlies all these aspects. The implementation of benefit sharing requires a value shift in which the outcomes of health science are not viewed simply as trade commodities but also as a "global public good". This approach should lead to genetic science to contribute to promoting the fundamental human right to health to all members of the global community.

mRNA Vaccine Platform: mRNA Production and Delivery

Vaccination is the most efficient way to prevent infectious diseases. mRNA-based vaccines is a new approach to vaccine development, which have several very useful advantages over other types of vaccines. Since mRNA encodes only the target antigen there is no potential risk of infection as in the case with attenuated or inactivated pathogens. The mode of action of mRNA-vaccines implies that their genetic information is expressed only in the cytosol, leaving very little possibility of mRNA integration into the host's genome. mRNA-vaccines can induce specific cellular and humoral immune responses, but do not induce the antivector immune response. The mRNA-vaccine platform allows for easy target gene replacement without the need to change the production technology, which is important to address the time lag between the epidemic onset and vaccine release. The present review discusses the history of mRNA vaccines, mRNA vaccine production technology, ways to increase mRNA stability, modifications of the cap, poly(A)-tail, coding and noncoding parts of mRNA, target mRNA vaccine purification from byproducts, and delivery methods.

COVID-19 adenovirus vector vaccine induces higher interferon and pro-inflammatory responses than mRNA vaccines in human PBMCs, macrophages and moDCs

BACKGROUND

During the COVID-19 pandemic multiple vaccines were rapidly developed and widely used throughout the world. At present there is very little information on COVID-19 vaccine interactions with primary human immune cells such as peripheral blood mononuclear cells (PBMCs), monocyte-derived macrophages and dendritic cells (moDCs).

METHODS

Human PBMCs, macrophages and moDCs were stimulated with different COVID-19 vaccines, and the expression of interferon (IFN-λ1, IFN-α1), pro-inflammatory (IL-1β, IL-6, IL-8, IL-18, CXCL-4, CXCL-10, TNF-α) and Th1-type cytokine mRNAs (IL-2, IFN-γ) were analyzed by qPCR. In addition, the expression of vaccine induced spike (S) protein and antiviral molecules were studied in primary immune cells and in A549 lung epithelial cells.

RESULTS

Adenovirus vector (Ad-vector) vaccine AZD1222 induced high levels of IFN-λ1, IFN-α1, CXCL-10, IL-6, and TNF-α mRNAs in PBMCs at early time points of stimulation while the expression of IFN-γ and IL-2 mRNA took place at later times. AZD1222 also induced IFN-λ1, CXCL-10 and IL-6 mRNA expression in monocyte-derived macrophages and DCs in a dose-dependent fashion. AZD1222 also activated the phosphorylation of IRF3 and induced MxA expression. BNT162b2 and mRNA-1273 mRNA vaccines failed to induce or induced very weak cytokine gene expression in all cell models. None of the vaccines enhanced the expression of CXCL-4. AZD1222 and mRNA-1273 vaccines induced high expression of S protein in all studied cells.

CONCLUSIONS

Ad-vector vaccine induces higher IFN and pro-inflammatory responses than the mRNA vaccines in human immune cells. This data shows that AZD1222 readily activates IFN and pro-inflammatory cytokine gene expression in PBMCs, macrophages and DCs, but fails to further enhance CXCL-4 mRNA expression.

Modeling mRNA-based vaccine YFV.E1988 against yellow fever virus E-protein using immuno-informatics and reverse vaccinology approach

To surmount constraints of live-attenuated vaccines we have in silico designed mRNA vaccine using envelope protein as a target antigen. From the alignment of 216 envelope proteins, a consensus sequence was obtained which was used for codon optimization. The secondary structure was predicted using Mfold and RNAfold tool. IEDB server was used to predict T-cell and B-cell epitopes, epitope conservancy, immunogenicity, and population coverage. Antigenicity, allergenicity, and toxicity were predicted using Vaxijen, AllerTOP, and ToxinPred tools, respectively. Interactions between MHC and identified epitopes were confirmed by docking and molecular dynamics simulation. In silico immune simulation was done using the C-ImmSim server. Vaccine peptide 3D structure was predicted and validated based on the Ramachandran plot. Finally, we designed the vaccine construct for simulating restriction cloning using the SnapGene tool. Our optimization of consensus E protein is highly immunogenic, conserved, has immune-dominance characteristics, and suggests high translational efficiency in the host cell. We validated the presence of T and B cell epitopes and interestingly we found one CD4+ and four CD8+ T-cell epitopes that satisfied all the criteria of an effective vaccine candidate. We found high-affinity interactions between epitope and HLA alleles that can stimulate the T-cell response. The immune simulation verified the immune cell response to eliminate the antigen. To ensure effective expression of the vaccine, a circular plasmid has been designed using in silico cloning approach for the in vitro transcription process. Obtained results suggest that the vaccine YFV.E1988 will elicit specific immune responses against YFV and it is a potential model ready for laboratory testing. HighlightsThe envelope (E) protein was found to be highly conserved and it has the potential to protect individuals against YFV infection.YFV.E1988 vaccine has been capable to stimulate both the CD8+ and CD4+ T cell, solving the major limitations of the current live-attenuated vaccines against YFV.Presence of T- and B-cell epitopes across the antigen have been validated using several computational tools.Molecular docking ensured the epitope-allele binding and protein-TLR/MR interaction. The vaccine was found to be immune-stimulatory, safe, and stable.The codons were optimized for efficient translation and increased stability into the human host. The UTR regions and poly (A) tail used for the development of YFV.E1988 showed immune stimulatory potential in several experiments.Communicated by Ramaswamy H. Sarma.

Meeting vaccine formulation challenges in an emergency setting: Towards the development of accessible vaccines

Vaccination is considered one of the most successful strategies to prevent infectious diseases. In the event of a pandemic or epidemic, the rapid development and distribution of the vaccine to the population is essential to reduce mortality, morbidity and transmission. As seen during the COVID-19 pandemic, the production and distribution of vaccines has been challenging, in particular for resource-constrained settings, essentially slowing down the process of achieving global coverage. Pricing, storage, transportation and delivery requirements of several vaccines developed in high-income countries resulted in limited access for low-and-middle income countries (LMICs). The capacity to manufacture vaccines locally would greatly improve global vaccine access. In particular, for the development of classical subunit vaccines, the access to vaccine adjuvants is a pre-requisite for more equitable access to vaccines. Vaccine adjuvants are agents required to augment or potentiate, and possibly target the specific immune response to such type of vaccine antigens. Openly accessible or locally produced vaccine adjuvants may allow for faster immunization of the global population. For local research and development of adjuvanted vaccines to expand, knowledge on vaccine formulation is of paramount importance. In this review, we aim to discuss the optimal characteristics of a vaccine developed in an emergency setting by focusing on the importance of vaccine formulation, appropriate use of adjuvants and how this may help overcome barriers for vaccine development and production in LMICs, achieve improved vaccine regimens, delivery and storage requirements.

A review on microfluidic-assisted nanoparticle synthesis, and their applications using multiscale simulation methods

Recent years have witnessed an increased interest in the development of nanoparticles (NPs) owing to their potential use in a wide variety of biomedical applications, including drug delivery, imaging agents, gene therapy, and vaccines, where recently, lipid nanoparticle mRNA-based vaccines were developed to prevent SARS-CoV-2 causing COVID-19. NPs typically fall into two broad categories: organic and inorganic. Organic NPs mainly include lipid-based and polymer-based nanoparticles, such as liposomes, solid lipid nanoparticles, polymersomes, dendrimers, and polymer micelles. Gold and silver NPs, iron oxide NPs, quantum dots, and carbon and silica-based nanomaterials make up the bulk of the inorganic NPs. These NPs are prepared using a variety of top-down and bottom-up approaches. Microfluidics provide an attractive synthesis alternative and is advantageous compared to the conventional bulk methods. The microfluidic mixing-based production methods offer better control in achieving the desired size, morphology, shape, size distribution, and surface properties of the synthesized NPs. The technology also exhibits excellent process repeatability, fast handling, less sample usage, and yields greater encapsulation efficiencies. In this article, we provide a comprehensive review of the microfluidic-based passive and active mixing techniques for NP synthesis, and their latest developments. Additionally, a summary of microfluidic devices used for NP production is presented. Nonetheless, despite significant advancements in the experimental procedures, complete details of a nanoparticle-based system cannot be deduced from the experiments alone, and thus, multiscale computer simulations are utilized to perform systematic investigations. The work also details the most common multiscale simulation methods and their advancements in unveiling critical mechanisms involved in nanoparticle synthesis and the interaction of nanoparticles with other entities, especially in biomedical and therapeutic systems. Finally, an analysis is provided on the challenges in microfluidics related to nanoparticle synthesis and applications, and the future perspectives, such as large-scale NP synthesis, and hybrid formulations and devices.

Why mRNA-ionizable LNPs formulations are so short-lived: causes and way-out

INTRODUCTION

Messenger ribonucleic acid (mRNA) and small interfering RNA (siRNA) are biological molecules that can be heated, frozen, lyophilized, precipitated, or re-suspended without degradation. Currently, ionizable lipid nanoparticles (LNPs) are a promising approach for mRNA therapy. However, the long-term shelf-life stability of mRNA-ionizable LNPs is one of the open questions about their use and safety. At an acidic pH, ionizable lipids shield anionic mRNA. However, the stability of mRNA under storage conditions remains a mystery. Moreover, ionizable LNPs excipients also cause instability during long-term storage.

AREA COVERED

This paper aims to illustrate why mRNA-ionizable LNPs have such a limited storage half-life. For the first time, we compile the tentative reasons for the short half-life and ultra-cold storage of mRNA-LNPs in the context of formulation excipients. The article also provided possible ways of prolonging the lifespan of mRNA-ionizable LNPs during long storage.

EXPERT OPINION

mRNA-ionizable LNPs are the future of genetic medicine. Current limitations of the formulation can be overcome by an advanced drying process or a whole new hybrid formulation strategy to extend the shelf life of mRNA-ionizable LNPs. A breakthrough technology may open up new research directions for producing thermostable and safe mRNA-ionizable LNPs at room temperature.

mRNA-From COVID-19 Treatment to Cancer Immunotherapy

This review provides an overview covering mRNA from its use in the COVID-19 pandemic to cancer immunotherapy, starting from the selection of appropriate antigens, tumor-associated and tumor-specific antigens, neoantigens, the basics of optimizing the mRNA molecule in terms of stability, efficacy, and tolerability, choosing the best formulation and the optimal route of administration, to summarizing current clinical trials of mRNA vaccines in tumor therapy.

mRNA Vaccines as an Efficient Approach for the Rapid and Robust Induction of Host Immunity Against SARS-CoV-2

Among the currently used COVID-19 vaccines, the mRNA-based vaccines drew the interest of the scientists because of its potent and versatile nature in mitigating the disease efficiently through increased translation as well as the robust modulation of the innate and adaptive immune responses within the host. The naked or lipid encapsulated mRNAs are usually optimized in order to formulate the vaccine. One of the interesting advantage of using mRNA vaccines is that such platform can even be used to mitigate other infectious diseases like influenza, zika, and rabies. However, the leading COVID-19 mRNA vaccines, i.e., mRNA-1273 and BNT162b2, have already been noticed to possess around 95% efficacy in provoking both the humoral and cell mediated immunity against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, causing the ongoing COVID-19 pandemic.

Liposomes and liposome-like nanoparticles: From anti-fungal infection to the COVID-19 pandemic treatment

The liposome is the first nanomedicine transformed into the market and applied to human patients. Since then, such phospholipid bilayer vesicles have undergone technological advancements in delivering small molecular-weight compounds and biological drugs. Numerous investigations about liposome uses were conducted in different treatment fields, including anti-tumor, anti-fungal, anti-bacterial, and clinical analgesia, owing to liposome's ability to reduce drug cytotoxicity and improve the therapeutic efficacy and combinatorial delivery. In particular, two liposomal vaccines were approved in 2021 to combat COVID-19. Herein, the clinically used liposomes are reviewed by introducing various liposomal preparations in detail that are currently proceeding in the clinic or on the market. Finally, we discuss the challenges of developing liposomes and cutting-edge liposomal delivery for biological drugs and combination therapy.

Preparation of RNAs with non-canonical 5' ends using novel di- and trinucleotide reagents for co-transcriptional capping

Many eukaryotic and some bacterial RNAs are modified at the 5' end by the addition of cap structures. In addition to the classic 7-methylguanosine 5' cap in eukaryotic mRNA, several non-canonical caps have recently been identified, including NAD-linked, FAD-linked, and UDP-glucose-linked RNAs. However, studies of the biochemical properties of these caps are impaired by the limited access to in vitro transcribed RNA probes of high quality, as the typical capping efficiencies with NAD or FAD dinucleotides achieved in the presence of T7 polymerase rarely exceed 50%, and pyrimidine derivatives are not incorporated because of promoter sequence limitations. To address this issue, we developed a series of di- and trinucleotide capping reagents and in vitro transcription conditions to provide straightforward access to unconventionally capped RNAs with improved 5'-end homogeneity. We show that because of the transcription start site flexibility of T7 polymerase, R1ppApG-type structures (where R1 is either nicotinamide riboside or riboflavin) are efficiently incorporated into RNA during transcription from dsDNA templates containing both φ 6.5 and φ 2.5 promoters and enable high capping efficiencies (∼90%). Moreover, uridine-initiated RNAs are accessible by transcription from templates containing the φ 6.5 promoter performed in the presence of R2ppUpG-type initiating nucleotides (where R2 is a sugar or phosphate moiety). We successfully employed this strategy to obtain several nucleotide-sugar-capped and uncapped RNAs. The capping reagents developed herein provide easy access to chemical probes to elucidate the biological roles of non-canonical RNA 5' capping.

Central Diabetes Insipidus Following Immunization With BNT162b2 mRNA COVID-19 Vaccine: A Case Report

Introduction

Cases of central diabetes insipidus (CDI) have been reported after COVID-19 infection, with hypophysitis being the most likely cause. COVID-19 vaccines potential adverse effects may mimetize some of these complications.

Case Report

Woman 37 years old, with rheumatoid arthritis under adalimumab (40 mg twice a month) since December 2018. She was in her usual state of health when she has received the second dose of BNT162b2 mRNA COVID-19 vaccine (June 2021). Seven days later, she started reporting intense thirst and polyuria and consulted her family physician.

Blood Analysis

creatinine 0.7 mg/dL, glucose 95mg/dL, Na+ 141mEq/L, K+ 3.9 mEq/L, TSH 3.8 mcUI/L (0.38-5.33), FT4 0.9 ng/dL (0.6-1.1), cortisol 215.4 nmol/L (185-624), ACTH 21.9 pg/mL (6- 48), FSH 4.76 UI/L, LH5.62 UI/L, estradiol 323 pmol/L, IGF1 74.8 ng/mL (88-209), PRL 24.7mcg/L (3.3-26.7) osmolality 298.2 mOs/Kg (250- 325); Urine analysis: volume 10200 mL/24h, osmolality 75 mOs/Kg (300-900), density 1.002. On water restriction test: 0' - Serum osmolality 308.8mOsm/Kg vs. urine osmolality 61.0 mOsm/Kg; 60' - urine osmolality 102 mOsm/Kg; urine osmolality 1 h after desmopressine was 511mOsm/kg. MRI revealed no abnormal signs consistent with hypophysitis except for the loss of the posterior pituitary bright spot on T1 weighted imaging. Diagnosis of CDI was assumed, and started therapy with desmopressine. A report of potential adverse effect was addressed to national health authorities.

Conclusion

In hypophysitis MRI often shows loss of posterior pituitary bright spot on T1 weighted imaging, pituitary enlargement or stalk thickening but those findings were not present in this patient. To the best of our knowledge, CDI has never been reported following administration of a COVID-19 vaccine.

Adenovirus-based vaccines-a platform for pandemic preparedness against emerging viral pathogens

Zoonotic viruses continually pose a pandemic threat. Infection of humans with viruses for which we typically have little or no prior immunity can result in epidemics with high morbidity and mortality. These epidemics can have public health and economic impact and can exacerbate civil unrest or political instability. Changes in human behavior in the past few decades-increased global travel, farming intensification, the exotic animal trade, and the impact of global warming on animal migratory patterns, habitats, and ecosystems-contribute to the increased frequency of cross-species transmission events. Investing in the pre-clinical advancement of vaccine candidates against diverse emerging viral threats is crucial for pandemic preparedness. Replication-defective adenoviral (Ad) vectors have demonstrated their utility as an outbreak-responsive vaccine platform during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Ad vectors are easy to engineer; are amenable to rapid, inexpensive manufacturing; are relatively safe and immunogenic in humans; and, importantly, do not require specialized cold-chain storage, making them an ideal platform for equitable global distribution or stockpiling. In this review, we discuss the progress in applying Ad-based vaccines against emerging viruses and summarize their global safety profile, as reflected by their widespread geographic use during the SARS-CoV-2 pandemic.

Nanotechnology-enabled immunoengineering approaches to advance therapeutic applications

Immunotherapy has reached clinical success in the last decade, with the emergence of new and effective treatments such as checkpoint blockade therapy and CAR T-cell therapy that have drastically improved patient outcomes. Still, these therapies can be improved to limit off-target effects, mitigate systemic toxicities, and increase overall efficacies. Nanoscale engineering offers strategies that enable researchers to attain these goals through the manipulation of immune cell functions, such as enhancing immunity against cancers and pathogens, controlling the site of immune response, and promoting tolerance via the delivery of small molecule drugs or biologics. By tuning the properties of the nanomaterials, such as size, shape, charge, and surface chemistry, different types of immune cells can be targeted and engineered, such as dendritic cells for immunization, or T cells for promoting adaptive immunity. Researchers have come to better understand the critical role the immune system plays in the progression of pathologies besides cancer, and developing nanoengineering approaches that seek to harness the potential of immune cell activities can lead to favorable outcomes for the treatment of injuries and diseases.

Cutaneous adverse reactions of COVID-19 vaccines: a systematic review

OBJECTIVE

Numerous vaccines are under clinical development and implementation for the prevention of severe course and lethal outcomes of coronavirus disease 2019 (COVID-19). This systematic review aims to summarize and integrated the findings of studies regarding cutaneous side effects of COVID-19 vaccines.

METHODS

This systematic review conducted by searching the scientific databases of PubMed, Scopus, Science direct, and Web of knowledge from the beginning of the COVID-19 to10/5/2021. Articles were reviewed and analyzed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

RESULTS

17 studies on cutaneous side effects of COVID-19 vaccines were included after the screening of search results based on to the eligibility criteria. The results showed that the most common injection site reactions and delayed large local reactions, arising from all vaccine types, were redness/ erythema (39%), followed by: itchiness (28%), urticarial rash (17%) on the neck, upper limbs, and trunk, morbilliform eruptions (6.5%), Pityriasis rosea (3%), swelling, and burning, etc. Most cutaneous reactions occurred in women (84%), and middle aged people, after the first dose of vaccine, with the onset ranged from 1-21 days after vaccination. In addition, cutaneous reactions were generally self-limiting, and needed little or no therapeutic intervention, that were not regarded as a barrier to injecting a second dose.

CONCLUSION

In conclusion, severe cutaneous side effects are very rare and approved vaccines have satisfactory safety profiles. Therefore, mild or moderate cutaneous reactions should not discourage people from vaccination. In certain groups such as patients with allergies and a history of local injection reactions, pre-vaccination counseling and assurance, also use of appropriate medications may be helpful. However, more studies are needed to investigate the side effect profile of all COVID-19 vaccines.

Principles for designing an optimal mRNA lipid nanoparticle vaccine

mRNA Lipid nanoparticles (LNPs) have recently been propelled onto the center stage of therapeutic platforms due to the success of the SARS-CoV-2 mRNA LNP vaccines (mRNA-1273 and BNT162b2), with billions of mRNA vaccine doses already shipped worldwide. While mRNA vaccines seem like an overnight success to some, they are in fact a result of decades of scientific research. The advantage of mRNA-LNP vaccines lies in the modularity of the platform and the rapid manufacturing capabilities. However, there is a multitude of choices to be made when designing an optimal mRNA-LNP vaccine regarding efficacy, stability and toxicity. Herein, we provide a brief on what we consider to be the most important aspects to cover when designing mRNA-LNPs from what is currently known and how to optimize them. Lastly, we give our perspective on which of these aspects is most crucial and what we believe are the next steps required to advance the field.

Antibody-Based Affinity Capture Combined with LC-MS Analysis for Identification of COVID-19 Disease Serum Biomarkers

Blood serum or plasma proteins are potentially useful in COVID-19 research as biomarkers for risk prediction, diagnosis, stratification, and treatment monitoring. However, serum protein-based biomarker identification and validation is complicated due to the wide concentration range of these proteins, which spans more than ten orders of magnitude. Here we present a combined affinity purification-liquid chromatography mass spectrometry approach which allows identification and quantitation of the most abundant serum proteins along with the nonspecifically bound and interaction proteins. This led to the reproducible identification of more than 100 proteins that were not specifically targeted by the affinity column. Many of these have already been implicated in COVID-19 disease.

Evaluation of neutralizing antibodies after vaccine BNT162b2: Preliminary data

It is well-known that the Coronavirus Disease 2019, which is caused by the beta-coronavirus severe acute respiratory syndrome (SARS-CoV-2), emerged in December 2019 followed by an outbreak first reported in Wuhan, China. Thus far, vaccination appears to be the only way to bring the pandemic to an end. In the present study, immunogenicity data was evaluated using LIAISON® SARS-CoV-2 TrimericS IgG assay (DiaSorin S.p.A) among a sample of 52 vaccinated healthcare workers, five of whom were previously infected with SARS-CoV-2 and 47 who were seronegative, over a time span of ≤90 days following the second dose of the BNT162b2 mRNA vaccine. The test detects antibodies against the Trimeric complex (S1, S2 and receptor binding domain). The overall mean value of the serum levels of IgG antibodies to SARS-CoV-2 30 days following the second dose of the vaccine was 1,901.8 binding arbitrary unit (BAU)/ml, after 60 days the mean value declined to 1,244.9 BAU/ml. The antibody levels then reached a plateau, as confirmed by the antibody test carried out 90 days following the second dose, which revealed a mean value of 1,032.4 BAU/ml (P<0.0001). A higher level was observed at all three times in male subjects compared with female subjects, and in younger male participants compared with female participants, although these differences did not reach a statistically significant level. Similarly, no significant difference was found in antibody values at different times according to age. After the second dose of the vaccine, two subjects were infected with SARS-CoV-2, and an increase in antibody values in the third assay was observed in both individuals.

mRNA Therapeutic Modalities Design, Formulation and Manufacturing under Pharma 4.0 Principles

In the quest for a formidable weapon against the SARS-CoV-2 pandemic, mRNA therapeutics have stolen the spotlight. mRNA vaccines are a prime example of the benefits of mRNA approaches towards a broad array of clinical entities and druggable targets. Amongst these benefits is the rapid cycle "from design to production" of an mRNA product compared to their peptide counterparts, the mutability of the production line should another target be chosen, the side-stepping of safety issues posed by DNA therapeutics being permanently integrated into the transfected cell's genome and the controlled precision over the translated peptides. Furthermore, mRNA applications are versatile: apart from vaccines it can be used as a replacement therapy, even to create chimeric antigen receptor T-cells or reprogram somatic cells. Still, the sudden global demand for mRNA has highlighted the shortcomings in its industrial production as well as its formulation, efficacy and applicability. Continuous, smart mRNA manufacturing 4.0 technologies have been recently proposed to address such challenges. In this work, we examine the lab and upscaled production of mRNA therapeutics, the mRNA modifications proposed that increase its efficacy and lower its immunogenicity, the vectors available for delivery and the stability considerations concerning long-term storage.

Where are the RNA vaccines for TB?

A simple mRNA vaccine was shown to protect mice against tuberculosis more than 15 years ago. Like COVID-19, tuberculosis is a respiratory infection killing over a million people per year. It too presents a global emergency. Can the stunning success of RNA vaccination against COVID-19 be replicated for TB?

The Critical Contribution of Pseudouridine to mRNA COVID-19 Vaccines

The current COVID-19 pandemic is a massive source of global disruption, having led so far to two hundred and fifty million COVID-19 cases and almost five million deaths worldwide. It was recognized in the beginning that only an effective vaccine could lead to a way out of the pandemic, and therefore the race for the COVID-19 vaccine started immediately, boosted by the availability of the viral sequence data. Two novel vaccine platforms, based on mRNA technology, were developed in 2020 by Pfizer-BioNTech and Moderna Therapeutics (comirnaty® and spikevax®, respectively), and were the first ones presenting efficacies higher than 90%. Both consisted of N1-methyl-pseudouridine-modified mRNA encoding the SARS-COVID-19 Spike protein and were delivered with a lipid nanoparticle (LNP) formulation. Because the delivery problem of ribonucleic acids had been known for decades, the success of LNPs was quickly hailed by many as the unsung hero of COVID-19 mRNA vaccines. However, the clinical trial efficacy results of the Curevac mRNA vaccine (CVnCoV) suggested that the delivery system was not the only key to the success. CVnCoV consisted of an unmodified mRNA (encoding the same spike protein as Moderna and Pfizer-BioNTech's mRNA vaccines) and was formulated with the same LNP as Pfizer-BioNTech's vaccine (Acuitas ALC-0315). However, its efficacy was only 48%. This striking difference in efficacy could be attributed to the presence of a critical RNA modification (N1-methyl-pseudouridine) in the Pfizer-BioNTech and Moderna's mRNA vaccines (but not in CVnCoV). Here we highlight the features of N1-methyl-pseudouridine and its contributions to mRNA vaccines.

High-affinity memory B cells induced by SARS-CoV-2 infection produce more plasmablasts and atypical memory B cells than those primed by mRNA vaccines

Although both infections and vaccines induce memory B cell (MBC) populations that participate in secondary immune responses, the MBCs generated in each case can differ. Here, we compare SARS-CoV-2 spike receptor binding domain (S1-RBD)-specific primary MBCs that form in response to infection or a single mRNA vaccination. Both primary MBC populations have similar frequencies in the blood and respond to a second S1-RBD exposure by rapidly producing plasmablasts with an abundant immunoglobulin (Ig)A⁺ subset and secondary MBCs that are mostly IgG⁺ and cross-react with the B.1.351 variant. However, infection-induced primary MBCs have better antigen-binding capacity and generate more plasmablasts and secondary MBCs of the classical and atypical subsets than do vaccine-induced primary MBCs. Our results suggest that infection-induced primary MBCs have undergone more affinity maturation than vaccine-induced primary MBCs and produce more robust secondary responses.

Challenges of Storage and Stability of mRNA-Based COVID-19 Vaccines

In December 2019, a new and highly pathogenic coronavirus emerged-coronavirus disease 2019 (COVID-19), a disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), quickly spread throughout the world. In response to this global pandemic, a few vaccines were allowed for emergency use, beginning in November 2020, of which the mRNA-based vaccines by Moderna (Moderna, Cambridge, MA, USA) and BioNTech (BioTech, Mainz, Germany)/Pfizer (Pfizer, New York, NY, USA) have been identified as the most effective ones. The mRNA platform allowed rapid development of vaccines, but their global use is limited by ultracold storage requirements. Most resource-poor countries do not have cold chain storage to execute mass vaccination. Therefore, determining strategies to increase stability of mRNA-based vaccines in relatively higher temperatures can be a game changer to address the current global pandemic and upcoming new waves. In this review, we summarized the current research strategies to enhance stability of the RNA vaccine delivery system.

Cutaneous Adverse Reactions to COVID-19 Vaccines: Insights from an Immuno-Dermatological Perspective

(1) Background: Numerous vaccines are under preclinical and clinical development for prevention of severe course and lethal outcome of coronavirus disease 2019 (COVID-19). In light of high efficacy rates and satisfactory safety profiles, some agents have already reached approval and are now distributed worldwide, with varying availability. Real-world data on cutaneous adverse drug reactions (ADRs) remain limited. (2) Methods: We performed a literature research concerning cutaneous ADRs to different COVID-19 vaccines, and incorporated our own experiences. (3) Results: Injection site reactions are the most frequent side effects arising from all vaccine types. Moreover, delayed cutaneous ADRs may occur after several days, either as a primary manifestation or as a flare of a pre-existing inflammatory dermatosis. Cutaneous ADRs may be divided according to their cytokine profile, based on the preponderance of specific T-cell subsets (i.e., Th1, Th2, Th17/22, Tregs). Specific cutaneous ADRs mimic immunogenic reactions to the natural infection with SARS-CoV-2, which is associated with an abundance of type I interferons. (4) Conclusions: Further studies are required in order to determine the best suitable vaccine type for individual groups of patients, including patients suffering from chronic inflammatory dermatoses.

Engineering of the current nucleoside-modified mRNA-LNP vaccines against SARS-CoV-2

Currently, there are over 230 different COVID-19 vaccines under development around the world. At least three decades of scientific development in RNA biology, immunology, structural biology, genetic engineering, chemical modification, and nanoparticle technologies allowed the accelerated development of fully synthetic messenger RNA (mRNA)-based vaccines within less than a year since the first report of a SARS-CoV-2 infection. mRNA-based vaccines have been shown to elicit broadly protective immune responses, with the added advantage of being amenable to rapid and flexible manufacturing processes. This review recapitulates current advances in engineering the first two SARS-CoV-2-spike-encoding nucleoside-modified mRNA vaccines, highlighting the strategies followed to potentiate their effectiveness and safety, thus facilitating an agile response to the current COVID-19 pandemic.

The 3M Concept: Biomedical Translational Imaging from Molecules to Mouse to Man

Imaging keeps pervading biomedical sciences from the nanoscale to the bedside. Connecting the hierarchical levels of biomedicine with relevant imaging approaches, however, remains a challenge.

Here we present a concept, called “3M”, which can deliver a question, formulated at the bedside, across the wide-ranging hierarchical organization of the living organism, from the molecular level, through the small-animal scale, to whole-body human functional imaging. We present an example of nanoparticle development pipeline extending from atomic force microscopy to pre-clinical whole body imaging methods to highlight the essential features of the 3M concept, which integrates multi-scale resolution and quantification into a single logical process.

Using the nanoscale to human clinical whole body approach, we present the successful development, characterisation and application of Prussian Blue nanoparticles for a variety of imaging modalities, extending it to isotope payload quantification and shape-biodistribution relationships.

The translation of an idea from the bedside to the molecular level and back requires a set of novel combinatorial imaging methodologies interconnected into a logical pipeline. The proposed integrative molecules-to-mouse-to-man (3M) approach offers a promising, clinically oriented toolkit that lends the prospect of obtaining an ever-increasing amount of correlated information from as small a voxel of the human body as possible.

Potential Therapeutic Targets and Vaccine Development for SARS-CoV-2/COVID-19 Pandemic Management: A Review on the Recent Update

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a highly pathogenic novel virus that has caused a massive pandemic called coronavirus disease 2019 (COVID-19) worldwide. Wuhan, a city in China became the epicenter of the outbreak of COVID-19 in December 2019. The disease was declared a pandemic globally by the World Health Organization (WHO) on 11 March 2020. SARS-CoV-2 is a beta CoV of the Coronaviridae family which usually causes respiratory symptoms that resemble common cold. Multiple countries have experienced multiple waves of the disease and scientific experts are consistently working to find answers to several unresolved questions, with the aim to find the most suitable ways to contain the virus. Furthermore, potential therapeutic strategies and vaccine development for COVID-19 management are also considered. Currently, substantial efforts have been made to develop successful and safe treatments and SARS-CoV-2 vaccines. Some vaccines, such as inactivated vaccines, nucleic acid-based, and vector-based vaccines, have entered phase 3 clinical trials. Additionally, diverse small molecule drugs, peptides and antibodies are being developed to treat COVID-19. We present here an overview of the virus interaction with the host and environment and anti-CoV therapeutic strategies; including vaccines and other methodologies, designed for prophylaxis and treatment of SARS-CoV-2 infection with the hope that this integrative analysis could help develop novel therapeutic approaches against COVID-19.

Messenger RNA expressing PfCSP induces functional, protective immune responses against malaria in mice

Human malaria affects the vast majority of the world's population with the Plasmodium falciparum species causing the highest rates of morbidity and mortality. With no licensed vaccine and leading candidates achieving suboptimal protection in the field, the need for an effective immunoprophylactic option continues to motivate the malaria research community to explore alternative technologies. Recent advances in the mRNA discipline have elevated the long-neglected platform to the forefront of infectious disease research. As the immunodominant coat protein of the invasive stage of the malaria parasite, circumsporozoite protein (PfCSP) was selected as the antigen of choice to assess the immunogenic and protective potential of an mRNA malaria vaccine. In mammalian cell transfection experiments, PfCSP mRNA was well expressed and cell associated. In the transition to an in vivo murine model, lipid nanoparticle (LNP) encapsulation was applied to protect and deliver the mRNA to the cell translation machinery and supply adjuvant activity. The immunogenic effect of an array of factors was explored, such as formulation, dose, number, and interval of immunizations. PfCSP mRNA-LNP achieved sterile protection against infection with two P. berghei PfCSP transgenic parasite strains, with mRNA dose and vaccination interval having a greater effect on outcome. This investigation serves as the assessment of pre-erythrocytic malaria, PfCSP mRNA vaccine candidate resulting in sterile protection, with numerous factors affecting protective efficacy, making it a compelling candidate for further investigation.

Implications of mRNA-based SARS-CoV-2 vaccination for cancer patients

SARS-CoV-2 infection and the resulting COVID-19 have afflicted millions of people in an ongoing worldwide pandemic. Safe and effective vaccination is needed urgently to protect not only the general population but also vulnerable subjects such as patients with cancer. Currently approved mRNA-based SARS-CoV-2 vaccines seem suitable for patients with cancer based on their mode of action, efficacy, and favorable safety profile reported in the general population. Here, we provide an overview of mRNA-based vaccines including their safety and efficacy. Extrapolating from insights gained from a different preventable viral infection, we review existing data on immunity against influenza A and B vaccines in patients with cancer. Finally, we discuss COVID-19 vaccination in light of the challenges specific to patients with cancer, such as factors that may hinder protective SARS-CoV-2 immune responses in the context of compromised immunity and the use of immune-suppressive or immune-modulating drugs.

Vaccine Strategy During the SARS-CoV-2 Pandemic: What School Nurses Need to Know

The National Association of School Nurses supports immunization to reduce the incidence of vaccine-preventable diseases. School nurses have the obligation to discern and understand vaccine strategies to aid in the advocacy and education of their school administrators, faculty, staff, students, and caregivers. Coronavirus disease 2019 (COVID-19) has spread to all continents, and the total number of those infected or immune through effective vaccination is well below the estimated need for herd immunity. To achieve herd immunity against the global outbreak of COVID-19, the rapid development of safe and effective vaccines is essential. Using multiple strategies and vaccine platforms to speed up the vaccine development process will inherently save more lives. Equipped with this knowledge of vaccine strategy, the school nurse can more aptly advocate for the use of the COVID-19 vaccines to move toward herd immunity in their communities.

DNA vaccination induced protective immunity against SARS CoV-2 infection in hamsterss

The development of efficient vaccines against COVID-19 is an emergent need for global public health. The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a major target for the COVID-19 vaccine. To quickly respond to the outbreak of the SARS-CoV-2 pandemic, a nucleic acid-based vaccine is a novel option, beyond the traditional inactivated virus vaccine or recombinant protein vaccine. Here, we report a DNA vaccine containing the spike gene for delivery via electroporation. The spike genes of SARS-CoV and SARS-CoV-2 were codon optimized for mammalian cell expression and then cloned into mammalian cell expression vectors, called pSARS-S and pSARS2-S, respectively. Spike protein expression was confirmed by immunoblotting after transient expression in HEK293T cells. After immunization, sera were collected for antigen-specific antibody and neutralizing antibody titer analyses. We found that both pSARS-S and pSARS2-S immunization induced similar levels of antibodies against S2 of SARS-CoV-2. In contrast, only pSARS2-S immunization induced antibodies against the receptor-binding domain of SARS-CoV-2. We further found that pSARS2-S immunization, but not pSARS-S immunization, could induce very high titers of neutralizing antibodies against SARS-CoV-2. We further analyzed SARS-CoV-2 S protein-specific T cell responses and found that the immune responses were biased toward Th1. Importantly, pSARS2-S immunization in hamsters could induce protective immunity against SARS-CoV-2 challenge in vivo. These data suggest that DNA vaccination could be a promising approach for protecting against COVID-19.

From Antisense RNA to RNA Modification: Therapeutic Potential of RNA-Based Technologies

Therapeutic oligonucleotides interact with a target RNA via Watson-Crick complementarity, affecting RNA-processing reactions such as mRNA degradation, pre-mRNA splicing, or mRNA translation. Since they were proposed decades ago, several have been approved for clinical use to correct genetic mutations. Three types of mechanisms of action (MoA) have emerged: RNase H-dependent degradation of mRNA directed by short chimeric antisense oligonucleotides (gapmers), correction of splicing defects via splice-modulation oligonucleotides, and interference of gene expression via short interfering RNAs (siRNAs). These antisense-based mechanisms can tackle several genetic disorders in a gene-specific manner, primarily by gene downregulation (gapmers and siRNAs) or splicing defects correction (exon-skipping oligos). Still, the challenge remains for the repair at the single-nucleotide level. The emerging field of epitranscriptomics and RNA modifications shows the enormous possibilities for recoding the transcriptome and repairing genetic mutations with high specificity while harnessing endogenously expressed RNA processing machinery. Some of these techniques have been proposed as alternatives to CRISPR-based technologies, where the exogenous gene-editing machinery needs to be delivered and expressed in the human cells to generate permanent (DNA) changes with unknown consequences. Here, we review the current FDA-approved antisense MoA (emphasizing some enabling technologies that contributed to their success) and three novel modalities based on post-transcriptional RNA modifications with therapeutic potential, including ADAR (Adenosine deaminases acting on RNA)-mediated RNA editing, targeted pseudouridylation, and 2′-O-methylation.

Cutaneous adverse effects of the available COVID-19 vaccines

Vaccination has played a crucial role in the improvement of global health. Some of the world's deadliest diseases, like smallpox and rinderpest, have been eradicated with the help of vaccines, and many others have been restrained. The appearance of the strain of coronavirus disease 2019 (COVID-19) severe acute respiratory syndrome coronavirus 2 and its impact on global health have made the development of effective and safe vaccines crucial for this new lethal disease. So far, there are three main types of COVID-19 vaccines in use around the world: messenger RNA-based vaccines, adenoviral vector vaccines, and inactivated whole-virus vaccines. Some of them have passed through phase 3 of safety and efficacy trials and are widely used for prophylaxis of COVID-19 infection. A plethora of cutaneous adverse events have been reported, most of them mild or moderate injection-site reactions. Some rare delayed inflammatory reactions such as "COVID arm" have also been reported, posing questions on their pathophysiology and clinical importance. Some rare serious adverse events, such as vaccine-induced prothrombotic immune thrombocytopenia and anaphylaxis, have been described raising great concerns on the safety of some widely spread vaccines. More data need to be collected with further and more detailed analysis. The overall risk of such severe adverse reactions remains extremely low, and the benefits of the existing vaccines in combating the widespread threat of COVID-19 continue to outweigh the risk of their side effects.

Review the safety of Covid-19 mRNA vaccines: a review

The novel coronavirus disease 2019 (COVID-19) has infected more than 100 million people globally within the first year of the pandemic. With a death toll surpassing 500,000 in the United States alone, containing the pandemic is predicated on achieving herd immunity on a global scale. This implies that at least 70-80 % of the population must achieve active immunity against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), either as a result of a previous COVID-19 infection or by vaccination against SARS-CoV-2. In December 2020, the first two vaccines were approved by the FDA through emergency use authorization in the United States. These vaccines are based on the mRNA vaccine platform and were developed by Pfizer/BioNTech and Moderna. Published safety and efficacy trials reported high efficacy rates of 94-95 % after two interval doses, in conjunction with limited side effects and a low rate of adverse reactions. The rapid pace of vaccine development and the uncertainty of potential long-term adverse effects raised some level of hesitation against mRNA vaccines in the global community. A successful vaccination campaign is contingent on widespread access to the vaccine under appropriate storage conditions, deployment of a sufficient number of vaccinators, and the willingness of the population to be vaccinated. Thus, it is important to clarify the objective data related to vaccine safety, including known side effects and potential adverse reactions. The present review was designed to provide an update on the current state of science related to the safety and efficacy of SARS-CoV-2 mRNA vaccines.

An Insight on RNA Based Therapeutics and Vaccines: Challenges and Opportunities

In this era, RNA molecules have provided a unique opportunity to researchers all over the world for expanding their range of targets in the development of drugs. Due to the unique pharmacological as well as physicochemical characteristics of different RNA molecules such as aptamers, small interfering RNAs (siRNA), antisense oligonucleotides (ASO) and guide RNAs (gRNA), they have emerged recently as a new class of drugs. They are used for selective action on proteins and genes that were not possible to target by conventional drug molecules. These RNA molecules like guide RNAs are also components of novel gene editing mechanisms which can modify the genome nearly in all cells. Vaccines based on RNA molecules have also provided a promising alternative to conventional live attenuated vaccines. RNA based vaccines have high potency, can be rapidly developed, and have potential for manufacturing at a cheaper rate and safe administration. However, the application of these RNAs has been restricted by the high instability and inefficient in vivo delivery. Technological advancement needs to overcome these issues so that RNA based drugs targeting several diseases can be developed. This article emphasizes the potential of RNA based drugs and the major barriers associated with the development of RNA therapeutics. Additionally, the role of RNA based vaccines and their challenges in advancing this promising vaccine platform for the prevention of infectious diseases have been discussed.