The Current Status of COVID-19 Vaccines

Determination of T cell response against XBB variants in adults who received either monovalent wild-type inactivated whole virus or mRNA vaccine or bivalent WT/BA.4-5 COVID-19 mRNA vaccine as the additional booster

OBJECTIVES

As the SARS-CoV-2 virus evolves more rapidly than vaccines are updated, T cell immunity potentially confers protection against disease progression and death from new variants. In this study, we aimed to assess whether the current boosting vaccination schemes offer sufficient T cell protection against new SARS-CoV-2 variants.

METHODS

A total of 292 adults who had received the second booster of either monovalent wild-type (WT) vaccines (inactivated virus or mRNA) (Cohort 1) or the second/third booster of bivalent WT/BA.4-5 mRNA vaccine (Cohort 2) were recruited in Hong Kong. All participants showed no serological evidence of recent infection of SARS-CoV-2. Blood samples of each participant were collected before and 1 month after receiving the booster. T cell and antibody responses were determined by flow cytometry and neutralization test, respectively.

RESULTS

Among all vaccination strategies, only the adults who had received the bivalent vaccine as the third booster dose significantly elicited T cell responses to the XBB variant. Either monovalent or bivalent mRNA but not inactivated virus vaccine as the second/third booster induced antibody against different XBB variants.

CONCLUSION

Receiving bivalent mRNA vaccine as the third booster is preferable to induce both T cell and antibody responses against XBB.

Autoimmune response after SARS-CoV-2 infection and SARS-CoV-2 vaccines

The complicated relationships between autoimmunity, COVID-19, and COVID-19 vaccinations are described, giving insight into their intricacies. Antinuclear antibodies (ANA), anti-Ro/SSA, rheumatoid factor, lupus anticoagulant, and antibodies against interferon (IFN)-I have all been consistently found in COVID-19 patients, indicating a high prevalence of autoimmune reactions following viral exposure. Furthermore, the discovery of human proteins with structural similarities to SARS-CoV-2 peptides as possible autoantigens highlights the complex interplay between the virus and the immune system in initiating autoimmunity. An updated summary of the current status of COVID-19 vaccines is presented. We present probable pathways underpinning the genesis of COVID-19 autoimmunity, such as bystander activation caused by hyperinflammatory conditions, viral persistence, and the creation of neutrophil extracellular traps. These pathways provide important insights into the development of autoimmune-related symptoms ranging from organ-specific to systemic autoimmune and inflammatory illnesses, demonstrating the wide influence of COVID-19 on the immune system.

Anti-SARS-CoV-2 (COVID-19) vaccination efficacy in patients with severe neuromuscular diseases

INTRODUCTION

Patients with severe neuromuscular disease (sNMD) are considered at high risk of severe COVID-19. Muscle tissue is often replaced by fibroadipose tissue in these diseases whereas the new mRNA-based vaccines are injected intramuscularly. We aimed at evaluating the efficacy of two injections associated with a booster injection of mRNA vaccine in these patients.

METHODS

We performed an observational, prospective, single-centre study to investigate the level of anti-S antibodies (Abs) and their neutralization activity at weeks 6 (W6) and 24 (W24) after two injections of mRNA-1273 vaccine and at weeks 12 (BW12) and 29 (BW29) after a booster injection of BNT162b2 vaccine in patients with sNMD.

RESULTS

Thirty-three patients with sNMD were included. At W6, 30 patients (90.1%) showed a protective serum level of specific anti-S Abs with a strong neutralization capacity. We observed a decline over time: only 12 patients (36.3%) retained anti-S Abs levels considered as protective at W24. The neutralization activity remained above the cut off in 23 (69.7%). The booster vaccination restored robust neutralization activity for all analysed 22 patients (100%) at BW12, which was maintained without any significant drop at BW29 (16). No severe adverse event was reported in this cohort and none of the 33 patients developed symptomatic COVID-19 over one year.

CONCLUSIONS

This study provides evidence that most sNMD patients receiving two injections of COVID-19 mRNA-based vaccines develop a strong humoral response after vaccination. A decline over time was observed but a single booster injection restores a long-term immunity. Moreover, no safety issues were observed.

Nano-based techniques: A revolutionary approach to prevent covid-19 and enhancing human awareness

In every century of history, there are many new diseases emerged, which are not even cured by many developed countries. Today, despite of scientific development, new deadly pandemic diseases are caused by microorganisms. Hygiene is considered to be one of the best methods of avoiding such communicable diseases, especially viral diseases. Illness caused by SARS-CoV-2 was termed COVID-19 by the WHO, the acronym derived from "coronavirus disease 2019. The globe is living in the worst epidemic era, with the highest infection and mortality rate owing to COVID-19 reaching 6.89% (data up to March 2023). In recent years, nano biotechnology has become a promising and visible field of nanotechnology. Interestingly, nanotechnology is being used to cure many ailments and it has revolutionized many aspects of our lives. Several COVID-19 diagnostic approaches based on nanomaterial have been developed. The various metal NPs, it is highly anticipated that could be viable and economical alternatives for treating drug resistant in many deadly pandemic diseases in near future. This review focuses on an overview of nanotechnology's increasing involvement in the diagnosis, prevention, and therapy of COVID-19, also this review provides readers with an awareness and knowledge of importance of hygiene.

An update on vaccine status and the role of nanomedicine against SARS-CoV-2: A narrative review

Background and Aims

Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 novel coronavirus, is a highly communicable disease that gave rise to the ongoing pandemic. Despite prompt action across many laboratories in many countries, effective management of this disease is still out of reach. The focus of this review is to describe various vaccination approaches and nanomedicine-based delivery systems against COVID-19.

Methods

The articles included in this study were searched and added from different electronic databases, including PubMed, Scopus, Cochrane, Embase, and preprint databases.

Results

Mass immunization with vaccines is currently at the forefront of COVID-19 infection control. Such vaccines are live attenuated vaccines, inactivated vaccines, nucleic acid-based vaccines, protein subunit vaccines, viral-vector vaccines, and virus-like particle platforms. However, many promising avenues are currently being explored in laboratory and clinical settings, including treatment options, prevention, diagnosis, and management of the disease. Soft nanoparticles like lipid nanoparticles (solid lipid nanoparticles (SLNPs), liposomes, nanostructured lipid carriers, nanoemulsions, and protein nanoparticles play an essential role in nanomedicine. Because of their unique and excellent properties, nanomedicines have potential applications in treating COVID-19 disease.

Conclusions

This review work provides an overview of the therapeutic aspects of COVID-19, including vaccination and the role of nanomedicines in the diagnosis, treatment, and prevention of COVID-19.

Bacillus subtilis spores displaying RBD domain of SARS-CoV-2 spike protein

Bacillus subtilis spores are considered to be efficient and useful vehicles for the surface display and delivery of heterologous proteins. In this study, we prepared recombinant spores with the receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein displayed on their surface in fusion with the CotZ or CotY spore coat proteins as a possible tool for the development of an oral vaccine against the SARS-CoV-2 virus. The RBD was attached to the N-terminus or C-terminus of the coat proteins. We also directly adsorbed non-recombinantly produced RBD to the spore surface. SDS-PAGE, western blot and fluorescence microscopy were used to analyze RBD surface expression on purified spores. Results obtained from both display systems, recombinant and non-recombinant, demonstrated that RBD was present on the spore surfaces.

Gene Therapy Cargoes Based on Viral Vector Delivery

Viral vectors have been proven useful in a broad spectrum of gene therapy applications due to their possibility to accommodate foreign genetic material for both local and systemic delivery. The wide range of viral vectors has enabled gene therapy applications for both acute and chronic diseases. Cancer gene therapy has been addressed by the delivery of viral vectors expressing anti-tumor, toxic, and suicide genes for the destruction of tumors. Delivery of immunostimulatory genes such as cytokines and chemokines has also been applied for cancer therapy. Moreover, oncolytic viruses specifically replicating in and killing tumor cells have been used as such for tumor eradication or in combination with tumor killing or immunostimulatory genes. In a broad meaning, vaccines against infectious diseases and various cancers can be considered gene therapy, which has been highly successful, not the least for the development of effective COVID-19 vaccines. Viral vector-based gene therapy has also demonstrated encouraging and promising results for chronic diseases such as severe combined immunodeficiency (SCID), muscular dystrophy, and hemophilia. Preclinical gene therapy studies in animal models have demonstrated proof-of-concept for a wide range of disease indications. Clinical evaluation of drugs and vaccines in humans has showed high safety levels, good tolerance, and therapeutic efficacy. Several gene therapy drugs such as the adenovirus-based drug Gendicine® for non-small-cell lung cancer, the reovirus-based drug Reolysin® for ovarian cancer, lentivirus-based treatment of SCID-X1 disease, and the rhabdovirus-based vaccine Ervebo against Ebola virus disease, and adenovirus-based vaccines against COVID-19 have been developed.

A Review of Different Vaccines and Strategies to Combat COVID-19

In December 2019, an unknown viral infection emerged and quickly spread worldwide, resulting in a global pandemic. This novel virus caused severe pneumonia and acute respiratory distress syndrome caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). It has caused 6.25 millions of deaths worldwide and remains a major concern for health, society, and the economy. As vaccination is one of the most efficient ways to combat this pandemic, different vaccines were developed in a short period. This review article discusses how coronavirus affected the top nations of the world and the vaccines being used for the prevention. Amongst the vaccines, some vaccines have already been approved, and some have been involved in clinical studies. The article also provides insight into different COVID-19 vaccine platforms, their preparation, working, efficacy, and side effects.

SARS-CoV-2 Virus-like Particles Produced by a Single Recombinant Baculovirus Generate Anti-S Antibody and Protect against Variant Challenge

Coronavirus Disease 2019 (COVID-19), caused by infection with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has highlighted the need for the rapid generation of efficient vaccines for emerging disease. Virus-like particles, VLPs, are an established vaccine technology that produces virus-like mimics, based on expression of the structural proteins of a target virus. SARS-CoV-2 is a coronavirus where the basis of VLP formation has been shown to be the co-expression of the spike, membrane and envelope structural proteins. Here we describe the generation of SARS-CoV-2 VLPs by the co-expression of the salient structural proteins in insect cells using the established baculovirus expression system. VLPs were heterologous ~100 nm diameter enveloped particles with a distinct fringe that reacted strongly with SARS-CoV-2 convalescent sera. In a Syrian hamster challenge model, non-adjuvanted VLPs induced neutralizing antibodies to the VLP-associated Wuhan S protein and reduced virus shedding and protected against disease associated weight loss following a virulent challenge with SARS-CoV-2 (B.1.1.7 variant). Immunized animals showed reduced lung pathology and lower challenge virus replication than the non-immunized controls. Our data suggest SARS-CoV-2 VLPs offer an efficient vaccine that mitigates against virus load and prevents severe disease.

Audiovestibular Disorders after COVID-19 Vaccine: Is There an Association?

The SARS-CoV-2 vaccination campaign is probably one of the most historic public hygiene measures in modern medicine. The drama of the pandemic has forced the scientific community to accelerate the development and commercialization of vaccines, thereby enhancing the phases of active surveillance. Among the adverse events following immunization (AEFI) reported, those of an audiovestibular interest, such as sudden sensorineural hearing loss (SSNHL), tinnitus, dizziness, and vertigo, constitute a very small percentage. There are many plausible etiological hypotheses, and scientific research needs to pay more attention to the correct collection of data, which up until now have often been inadequate and fragmented, on which to base future studies. SSNHL, new onset tinnitus, vertigo, and dizziness require a prompt evaluation, while the proposed treatment is the same as it is for events unrelated to vaccination. These are uncommon adverse events, and the risk rates for these diseases have not increased in conjunction with the COVID-19 vaccinations, therefore there is no justification of any hesitation towards the vaccination campaign.

SARS-CoV-2 Vaccination and the Bridge between First and Fourth Dose: Where Are We?

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has induced the explosion of vaccine research. Currently, according to the data of the World Health Organization, there are several vaccines in clinical (145) and preclinical (195) stages, while at least 10 are already in clinical phase 4 (post-marketing). Vaccines have proven to be safe, effective, and able to reduce the spread of SARS-CoV-2 infection and its variants, as well as the clinical consequences of the development of coronavirus disease-19 (COVID-19). In the two-dose primary vaccination, different time intervals between the two doses have been used. Recently, special attention has been paid to assessing the immunogenicity following booster administration. The third dose of the vaccine against COVID-19 may be administered at least 8 weeks after the second dose. In Israel, a fourth dose has already been approved in immunocompromised groups. The main objective of this review is to describe the principal results of studies on the effectiveness of first-to-fourth dose vaccination to reduce reinfection by variants and the incidence of severe disease/death caused by COVID-19. Vaccines have shown a high level of protection from symptomatic infection and reinfection by variants after a third dose. Accelerating mass third-dose vaccination could potentially induce immunogenicity against variants.

Review: A systematic review of virus-like particles of coronavirus: Assembly, generation, chimerism and their application in basic research and in the clinic

Virus-like particles (VLPs) are nano-scale particles that are morphologically similar to a live virus but which lack a genetic component. Since the pandemic spread of COVID-19, much focus has been placed on coronavirus (CoV)-related VLPs. CoVs contain four structural proteins, though the minimum requirement for VLP formation differs among virus species. CoV VLPs are commonly produced in mammalian and insect cell systems, sometimes in the form of chimeric VLPs that enable surface display of CoV epitopes. VLPs are an ideal model for virological research and have been applied as vaccines and diagnostic reagents to aid in clinical disease control. This review summarizes and updates the research progress on the characteristics of VLPs from different known CoVs, mainly focusing on assembly, in vitro expression systems for VLP generation, VLP chimerism, protein-based nanoparticles and their applications in basic research and clinical settings, which may aid in development of novel VLP vaccines against emerging coronavirus diseases such as SARS-CoV-2.

The Remarkable Evolutionary Plasticity of Coronaviruses by Mutation and Recombination: Insights for the COVID-19 Pandemic and the Future Evolutionary Paths of SARS-CoV-2

Coronaviruses (CoVs) constitute a large and diverse subfamily of positive-sense single-stranded RNA viruses. They are found in many mammals and birds and have great importance for the health of humans and farm animals. The current SARS-CoV-2 pandemic, as well as many previous epidemics in humans that were of zoonotic origin, highlights the importance of studying the evolution of the entire CoV subfamily in order to understand how novel strains emerge and which molecular processes affect their adaptation, transmissibility, host/tissue tropism, and patho non-homologous genicity. In this review, we focus on studies over the last two years that reveal the impact of point mutations, insertions/deletions, and intratypic/intertypic homologous and non-homologous recombination events on the evolution of CoVs. We discuss whether the next generations of CoV vaccines should be directed against other CoV proteins in addition to or instead of spike. Based on the observed patterns of molecular evolution for the entire subfamily, we discuss five scenarios for the future evolutionary path of SARS-CoV-2 and the COVID-19 pandemic. Finally, within this evolutionary context, we discuss the recently emerged Omicron (B.1.1.529) VoC.

Nucleic Acid-Based Treatments Against COVID-19: Potential Efficacy of Aptamers and siRNAs

Despite significant efforts, there are currently no approved treatments for COVID-19. However, biotechnological approaches appear to be promising in the treatment of the disease. Accordingly, nucleic acid-based treatments including aptamers and siRNAs are candidates that might be effective in COVID-19 treatment. Aptamers can hamper entry and replication stages of the SARS-CoV-2 infection, while siRNAs can cleave the viral genomic and subgenomic RNAs to inhibit the viral life cycle and reduce viral loads. As a conjugated molecule, aptamer–siRNA chimeras have proven to be dual-functioning antiviral therapy, acting both as virus-neutralizing and replication-interfering agents as well as being a siRNA targeted delivery approach. Previous successful applications of these compounds against various stages of the pathogenesis of diseases and viral infections, besides their advantages over other alternatives, might provide sufficient rationale for the application of these nucleic acid-based drugs against the SARS-CoV-2. However, none of them are devoid of limitations. Here, the literature was reviewed to assess the plausibility of using aptamers, siRNAs, and aptamer–siRNA chimeras against the SARS-CoV-2 based on their previously established effectiveness, and discussing challenges lie in applying these molecules.

COVID-19 Pandemic and Vaccines Update on Challenges and Resolutions

The coronavirus disease (COVID-19) is caused by a positive-stranded RNA virus called severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), belonging to the Coronaviridae family. This virus originated in Wuhan City, China, and became the cause of a multiwave pandemic that has killed 3.46 million people worldwide as of May 22, 2021. The havoc intensified with the emergence of SARS-CoV-2 variants (B.1.1.7; Alpha, B.1.351; Beta, P.1; Gamma, B.1.617; Delta, B.1.617.2; Delta-plus, B.1.525; Eta, and B.1.429; Epsilon etc.) due to mutations generated during replication. More variants may emerge to cause additional pandemic waves. The most promising approach for combating viruses and their emerging variants lies in prophylactic vaccines. Several vaccine candidates are being developed using various platforms, including nucleic acids, live attenuated virus, inactivated virus, viral vectors, and protein-based subunit vaccines. In this unprecedented time, 12 vaccines against SARS-CoV-2 have been phased in following WHO approval, 184 are in the preclinical stage, and 100 are in the clinical development process. Many of them are directed to elicit neutralizing antibodies against the viral spike protein (S) to inhibit viral entry through the ACE-2 receptor of host cells. Inactivated vaccines, to the contrary, provide a wide range of viral antigens for immune activation. Being an intracellular pathogen, the cytotoxic CD8+ T Cell (CTL) response remains crucial for all viruses, including SARS-CoV-2, and needs to be explored in detail. In this review, we try to describe and compare approved vaccines against SARS-CoV-2 that are currently being distributed either after phase III clinical trials or for emergency use. We discuss immune responses induced by various candidate vaccine formulations; their benefits, potential limitations, and effectiveness against variants; future challenges, such as antibody-dependent enhancement (ADE); and vaccine safety issues and their possible resolutions. Most of the current vaccines developed against SARS-CoV-2 are showing either promising or compromised efficacy against new variants. Multiple antigen-based vaccines (multivariant vaccines) should be developed on different platforms to tackle future variants. Alternatively, recombinant BCG, containing SARS-CoV-2 multiple antigens, as a live attenuated vaccine should be explored for long-term protection. Irrespective of their efficacy, all vaccines are efficient in providing protection from disease severity. We must insist on vaccine compliance for all age groups and work on vaccine hesitancy globally to achieve herd immunity and, eventually, to curb this pandemic.

Clinical approval of nanotechnology-based SARS-CoV-2 mRNA vaccines: impact on translational nanomedicine

One year after the first human case of SARS-CoV-2, two nanomedicine-based mRNA vaccines have been fast-tracked, developed, and have received emergency use authorization throughout the globe with more vaccine approvals on the heels of these first two. Several SARS-CoV-2 vaccine compositions use nanotechnology-enabled formulations. A silver lining of the COVID-19 pandemic is that the fast-tracked vaccine development for SARS-CoV-2 has advanced the clinical translation pathway for nanomedicine drug delivery systems. The laboratory science of lipid-based nanoparticles was ready and rose to the clinical challenge of rapid vaccine development. The successful development and fast tracking of SARS-CoV-2 nanomedicine vaccines has exciting implications for the future of nanotechnology-enabled drug and gene delivery; it demonstrates that nanomedicine is necessary and critical to the successful delivery of advanced molecular therapeutics such as nucleic acids, it is establishing the precedent of safety and the population effect of phase four clinical trials, and it is laying the foundation for the clinical translation of more complex, non-lipid nanomedicines. The development, fast-tracking, and approval of SARS-CoV-2 nanotechnology-based vaccines has transformed the seemingly daunting challenges for clinically translating nanomedicines into measurable hurdles that can be overcome. Due to the tremendous scientific achievements that have occurred in response to the COVID-19 pandemic, years, perhaps even decades, have been streamlined for certain translational nanomedicines.

Altering Compositional Properties of Viral Genomes to Design Live-Attenuated Vaccines

Live-attenuated vaccines have been historically used to successfully prevent numerous diseases caused by a broad variety of RNA viruses due to their ability to elicit strong and perdurable immune-protective responses. In recent years, various strategies have been explored to achieve viral attenuation by rational genetic design rather than using classic and empirical approaches, based on successive passages in cell culture. A deeper understanding of evolutionary implications of distinct viral genomic compositional aspects, as well as substantial advances in synthetic biology technologies, have provided a framework to achieve new viral attenuation strategies. Herein, we will discuss different approaches that are currently applied to modify compositional features of viruses in order to develop novel live-attenuated vaccines.

Charge-Conversion Strategies for Nucleic Acid Delivery

Nucleic acids are now considered as one of the most potent therapeutic modalities, as their roles go beyond storing genetic information and chemical energy or as signal transducer. Attenuation or expression of desired genes through nucleic acids have profound implications in gene therapy, gene editing and even in vaccine development for immunomodulation. Although nucleic acid therapeutics bring in overwhelming possibilities towards the development of molecular medicines, there are significant loopholes in designing and effective translation of these drugs into the clinic. One of the major pitfalls lies in the traditional design concepts for nucleic acid drug carriers, viz. cationic charge induced cytotoxicity in delivery pathway. Targeting this bottleneck, several pioneering research efforts have been devoted to design innovative carriers through charge-conversion approaches, whereby built-in functionalities convert from cationic to neutral or anionic, or even from anionic to cationic enabling the carrier to overcome several critical barriers for therapeutics delivery, such as serum deactivation, instability in circulation, low transfection and poor endosomal escape. This review will critically analyze various molecular designs of charge-converting nanocarriers in a classified approach for the successful delivery of nucleic acids. Accompanied by the narrative on recent clinical nucleic acid candidates, the review concludes with a discussion on the pitfalls and scope of these interesting approaches.

Application of Viral Vectors for Vaccine Development with a Special Emphasis on COVID-19

Viral vectors can generate high levels of recombinant protein expression providing the basis for modern vaccine development. A large number of different viral vector expression systems have been utilized for targeting viral surface proteins and tumor-associated antigens. Immunization studies in preclinical animal models have evaluated the elicited humoral and cellular responses and the possible protection against challenges with lethal doses of infectious pathogens or tumor cells. Several vaccine candidates for both infectious diseases and various cancers have been subjected to a number of clinical trials. Human immunization trials have confirmed safe application of viral vectors, generation of neutralizing antibodies and protection against challenges with lethal doses. A special emphasis is placed on COVID-19 vaccines based on viral vectors. Likewise, the flexibility and advantages of applying viral particles, RNA replicons and DNA replicon vectors of self-replicating RNA viruses for vaccine development are presented.