The development of DNA vaccines against SARS-CoV-2

An mRNA vaccine candidate encoding cholera toxin subunit B and conserved antigens of influenza viruses confers cross-protection against influenza a viruses in adult and aged mice

Currently, vaccination with influenza vaccines is still an effective strategy to prevent infection by seasonal influenza virus. However, seasonal influenza vaccines frequently fail to induce effective immune protection against rapidly changing seasonal influenza viruses and emerging zoonotic influenza viruses. In addition, seasonal influenza vaccines may not confer potent protection in elderly and immunocompromised individuals. There is an urgent need to develop potent broad-spectrum influenza vaccines to address this problem. Herein, we designed an mRNA-based broad-spectrum influenza vaccine candidate encoding cholera toxin subunit B and conserved antigens of influenza viruses. In both adult and aged mice, this universal influenza mRNA vaccine candidate stimulated robust T-cell and humoral immune responses and conferred effective protection against broad-spectrum influenza viruses in both adult and aged mice.

Looking beyond the origin of SARS-CoV-2: Significant strategic aspects during the five-year journey of COVID-19 vaccine development

It has been five years since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and we are also approaching the five-year mark of the COVID-19 pandemic. The vaccine is a significant weapon in combating infectious diseases like SARS-CoV-2. Several vaccines were developed against SARS-CoV-2, and they demonstrated efficacy and safety during these five years. The rapid development of multiple next-generation vaccine candidates in different platforms with very little time is the success story of the vaccine development endeavor. This remarkable success of rapid vaccine development is a new paradigm for fast vaccine development that might help develop infectious diseases and fight against the pandemic. With the completion of five years since the beginning of SARS-CoV-2 origin, we are looking back on the five years and reviewing the milestones, vaccine platforms, animal models, clinical trials, successful collaborations, vaccine safety, real-world effectiveness, and challenges. Lessons learned during these five years will help us respond to public health emergencies and to fight the battle against future pandemics.

Research progress on Haemophilus parasuis vaccines

Haemophilus parasuis (HPS) is the causative agent of porcine Glässer's disease, which has become prevalent in China in recent years. It is characterized by fibrinous polyserositis, arthritis, and meningitis, but often shows mixed infection with other upper respiratory tract pathogens, causing heavy economic losses to the pig industry. Vaccination is an important means to prevent and control HPS infection, and the currently available vaccines are mainly the inactivated type or subunit vaccines containing immunogenic HPS proteins. This study reviews recent advances in HPS vaccines, analyzes the relative effectiveness of the components of subunit vaccines and discusses the advantages and disadvantages of each vaccine type. The goal is to provide insights for the development of more effective vaccines against Haemophilus parasuis infections in pigs.

Comparison of Phenotypes of Headaches After COVID-19 Vaccinations Differentiated According to the Vaccine Used

Background/Objectives: In this ongoing, multicenter, global cohort observational study, phenotypes of headaches after COVID-19 vaccination were directly compared between different vaccines. Methods: Phenotypes of postvaccinal headache were recorded in 18,544 participants. The study was launched immediately after the start of the global COVID-19 vaccination campaign on 12 January 2021 and continued until 1 August 2023. Specific aspects of headaches and related variables were collected via an online questionnaire. The clinical headache characteristics of patients vaccinated with the Comirnaty (BioNTech), Jcovden (Johnson & Johnson), Sputnik V (Gamelaya), Covilo (Sinopharm), Spikevax (Moderna), Vaxzevria (AstraZeneca), and Convidecia (CanSino Biologics) vaccines were investigated. Results: Across all vaccines, the median and mean latency of headache onset after vaccine administration were 12 h and 23.3 h, respectively. The median and mean headache duration were 12 h and 23.3 h, respectively. When the nonreplicating viral vector vaccine Sputnik V was used, headaches occurred the fastest, with a latency of 17 h. The latencies for the Vaxzevria and Convidecia nonreplicating viral vector vaccines were 14.9 h and 19.1 h, respectively. The Covilo inactivated whole-virus vaccine had a latency of 20.5 h. The latencies of the mRNA-based Comirnaty and Spikevax vaccines were 26.0 h and 22.02 h, respectively. Analysis of variance revealed no significant differences in the mean duration of postvaccinal headache for the vaccines tested. Compared with the Comirnaty, Covilo, and Vaxzevria vaccines, the Spikevax vaccine induced significantly greater headache intensities. Vaxzevria was associated with a significantly higher frequency of concomitant symptoms than the other vaccines. Conclusions: The phenotype of postvaccinal headache can vary significantly between vaccines. These results have clinical implications for differentiating between postvaccinal headache and other primary and secondary headaches. This knowledge is clinically relevant in differentiating life-threatening vaccination complications, such as thrombotic syndromes, which are also associated with headaches. Based on these results, new diagnostic criteria for postvaccinal headaches can be developed.

A Bibliometric Analysis on Multi-epitope Vaccine Development Against SARS-CoV-2: Current Status, Development, and Future Directions

The etiological agent for the coronavirus disease 2019 (COVID-19), the SARS-CoV-2, caused a global pandemic. Although mRNA, viral-vectored, DNA, and recombinant protein vaccine candidates were effective against the SARS-CoV-2 Wuhan strain, the emergence of SARS-CoV-2 variants of concern (VOCs) reduced the protective efficacies of these vaccines. This necessitates the need for effective and accelerated vaccine development against mutated VOCs. The development of multi-epitope vaccines against SARS-CoV-2 based on in silico identification of highly conserved and immunogenic epitopes is a promising strategy for future SARS-CoV-2 vaccine development. Considering the evolving landscape of the COVID-19 pandemic, we have conducted a bibliometric analysis to consolidate current findings and research trends in multi-epitope vaccine development to provide insights for future vaccine development strategies. Analysis of 102 publications on multi-epitope vaccine development against SARS-CoV-2 revealed significant growth and global collaboration, with India leading in the number of publications, along with an identification of the most prolific authors. Key journals included the Journal of Biomolecular Structure and Dynamics, while top collaborations involved Pakistan-China and India-USA. Keyword analysis showed a prominent focus on immunoinformatics, epitope prediction, and spike glycoprotein. Advances in immunoinformatics, including AI-driven epitope prediction, offer promising avenues for the development of safe and effective multi-epitope vaccines. Immunogenicity may be further improved through nanoparticle-based systems or the use of adjuvants along with real-time genomic surveillance to tailor vaccines against emerging variants.

COVID-19 vaccines: current and future challenges

As of December 2020, around 200 vaccine candidates for Coronavirus Disease 2019 (COVID-19) are being developed. COVID-19 vaccines have been created on a number of platforms and are still being developed. Nucleic acid (DNA, RNA) vaccines, viral vector vaccines, inactivated vaccines, protein subunit vaccines, and live attenuated vaccines are among the COVID-19 vaccine modalities. At this time, at least 52 candidate vaccines are being studied. Spike protein is the primary protein that COVID-19 vaccines are targeting. Therefore, it is critical to determine whether immunizations provide complete or fractional protection, whether this varies with age, whether vaccinated people are protected from reoccurring diseases, and whether they need booster shots if they've already been inoculated. Despite the enormous achievement of bringing several vaccine candidates to market in less than a year, acquiring herd immunity at the national level and much more so at the global level remains a major challenge. Therefore, we gathered information on the mechanism of action of presently available COVID-19 vaccines in this review and essential data on the vaccines' advantages and downsides and their future possibilities.

Coronavirus nucleocapsid-based vaccine provides partial protection against hetero-species coronavirus in murine models

Most coronavirus vaccines focus on the spike (S) antigen, but the frequent mutations in S raise concerns about the vaccine efficacy against new variants. Although additional antigens with conserved sequences are have been tested, the extent to which these vaccines can provide immunity against different coronavirus species remains unclear. In this study, we assessed the potential of nucleocapsid (N) as a coronavirus vaccine antigen. Immunization with MERS-CoV N induced robust immune responses, providing significant protection against MERS-CoV. Notably, MERS-CoV N elicited cross-reactive T cell responses to SARS-CoV-2 N and significantly reduced lung inflammation following a SARS-CoV-2 challenge in the transient hACE2 mouse model. However, in K18-hACE transgenic mice, the vaccine showed limited protection. Collectively, our findings suggest that coronavirus N can be an effective vaccine antigen against homologous viruses, but its efficacy may vary across different coronaviruses, highlighting the need for further research on pan-coronavirus vaccines using conserved antigens.

COVID-19: vaccination, therapeutics and a review of the science and public health

COVID-19, stemming from the SARS-CoV-2 virus, has initiated a worldwide respiratory pandemic. Remarkable headway has been made in the realm of vaccination, as nearly every nation has initiated COVID-19 vaccine deployment. However, a mere 32.6% of individuals in low-income countries have received only a single vaccine dose. Unprecedented research and development endeavors have yielded over 170 COVID-19 vaccines, several of which are now in practical use. These vaccines have demonstrated remarkable efficacy in averting severe illness, hospitalization, and fatalities from COVID-19, even against emerging variants. Research pursuits persist, concentrating on novel vaccine technologies, oral and nasal vaccines, broader coronavirus protection, and vaccine combinations. In the realm of therapeutics, there have been significant strides in developing oral antiviral medications and monoclonal antibodies. Nonetheless, challenges in COVID-19 vaccination persist, encompassing issues of hesitancy, accessibility, financial barriers, knowledge gaps, and logistical hindrances. Robust monitoring via global agencies and reporting systems remains pivotal. Strategies for enhancing vaccination efficacy are rooted in fostering trust, countering misinformation, and expanding access. As for therapeutics, the approach involves dedicated research, clinical trials, regulatory streamlining, stockpiling, and international collaboration. Telemedicine and public awareness campaigns play integral roles in this effort, with coordination being the linchpin for preserving lives and mitigating the disease's impact. The global campaign against COVID-19 has witnessed substantial advancements, with an ongoing research focus on developing vaccines and therapeutics that are not only more accessible and affordable but also more effective, particularly for populations in low-income countries and vulnerable communities.

Rapid production of COVID-19 subunit vaccine candidates and their immunogenicity evaluation in pigs

The emergence of various variants of concern (VOCs) necessitates the development of more efficient vaccines for COVID-19. In this study, we established a rapid and robust production platform for a novel subunit vaccine candidate based on eukaryotic HEK-293 T cells. The immunogenicity of the vaccine candidate was evaluated in pigs. The results demonstrated that the pseudovirus neutralizing antibody (pNAb) titers reached 7751 and 306 for the SARS-CoV-2 Delta and Omicron variants, respectively, after the first boost. Subsequently, pNAb titers further increased to 10,201 and 1350, respectively, after the second boost. Additionally, ELISPOT analysis revealed a robust T-cell response characterized by IFN-γ (171 SFCs/106 cells) and IL-2 (101 SFCs/106 cells) production. Our study demonstrates that a vaccine candidate based on the Delta variant spike protein may provide strong and broad protection against the prototype SARS-CoV-2 and VOCs. Moreover, the strategy for the efficient and stable expression of recombinant proteins utilizing HEK-293 T cells can be employed as a universal platform for future vaccine development.

Shaping immunity against infectious diseases with multivalent DNA vaccines

Immunization has dramatically transformed human and animal health. Since its earliest days, vaccination has served as a fundamental strategy for infectious disease prevention, providing population-level coverage for childhood diseases and seasonal infections, and serving as a rapid response to pandemic pathogens. Yet, there is continued circulation of endemic, emerging, and reemerging pathogens for which there are no licensed prophylactic measures. The successes of nucleic acid technologies during the COVID-19 pandemic, exemplified in the first two licensed mRNA vaccines [1] and the first DNA vaccine receiving emergency use authorization for human use [2], are reinvigorating vaccine development to tackle this urgent unmet need. The inherent stability of DNA offers advantageous features such as thermostability and extended shelf life. These characteristics are pivotal for transport and storage in resource-constrained environments, like low and middle-income countries. Furthermore, the ability to encode large transgenes and well-established modular assembly pipelines are key attributes of DNA-based platforms. This versatility extends to combination strategies of individual DNA vaccines as a multivalent drug product. Multivalent synthetic DNA vaccines are therefore emerging as part of the exciting nucleic acid-based vaccine landscape as a strategy to induce robust and durable immunity in diverse global populations.

To be remembered: B cell memory response against SARS-CoV-2 and its variants in vaccinated and unvaccinated individuals

COVID-19 disease has plagued the world economy and affected the overall well-being and life of most of the people. Natural infection as well as vaccination leads to the development of an immune response against the pathogen. This involves the production of antibodies, which can neutralize the virus during future challenges. In addition, the development of cellular immune memory with memory B and T cells provides long-lasting protection. The longevity of the immune response has been a subject of intensive research in this field. The extent of immunity conferred by different forms of vaccination or natural infections remained debatable for long. Hence, understanding the effectiveness of these responses among different groups of people can assist government organizations in making informed policy decisions. In this article, based on the publicly available data, we have reviewed the memory response generated by some of the vaccines against SARS-CoV-2 and its variants, particularly B cell memory in different groups of individuals.

Innovative translational platforms for rapid developing clinical vaccines against COVID-19 and other infectious disease

A vaccine is a biological preparation that contains the antigen capable of stimulating the immune system to form the defense against pathogens. Vaccine development often confronts big challenges, including time/energy-consuming, low efficacy, lag to pathogen emergence and mutation, and even safety concern. However, these seem now mostly conquerable through constructing the advanced translational platforms that can make innovative vaccines, sometimes, potentiated with a distinct multifunctional VADS (vaccine adjuvant delivery system), as evidenced by the development of various vaccines against the covid-19 pandemic at warp speed. Particularly, several covid-19 vaccines, such as the viral-vectored vaccines, mRNA vaccines and DNA vaccines, regarded as the innovative ones that are rapidly made via the high technology-based translational platforms. These products have manifested powerful efficacy while showing no unacceptable safety profile in clinics, allowing them to be approved for massive vaccination at also warp speed. Now, the proprietary translational platforms integrated with the state-of-the-art biotechnologies, and even the artificial intelligence (AI), represent an efficient mode for rapid making innovative clinical vaccines against infections, thus increasingly attracting interests of vaccine research and development. Herein, the advanced translational platforms for making innovative vaccines, together with their design principles and immunostimulatory efficacies, are comprehensively elaborated.

A review on the current approaches and perspectives of Covid-19 treatment

At the beginning of 2020, the world was faced with the challenge of the coronavirus disease 2019 (COVID-19) pandemic announced by the WHO on March 11, caused by the betacoronavirus type 2 of the severe acute respiratory syndrome (SARS-CoV-2), which had profound health, sociological and even economic consequences. The quickly implemented and large-scale research resulted in the introduction of widely available vaccines that reduced the further development of the pandemic and antivirals against SARS-CoV-2. Currently, 11 antiviral drugs (Tixagevimab/Cilgavimab, Regdanvimab, Casirivimab/Imdevimab, Sotrovimab, Nirmatrelvir/Ritonavir, Remdesivir, Molnupiravir, Baricitinib, Anakinra, Tocilizumab, Vilobelimab) have been approved or conditionally approved by the European Medicines Agency and/or by the Food and Drug Administration and are available on the pharmaceutical market. The progress in the pathophysiological description of the SARS-CoV-2 infection has allowed the identif i cation of potential targets for drugs against SARS-CoV-2: inhibitors of intracellular entry of the virus (the interaction between the viral spike (S) protein and the cellular angiotensin converting enzyme-2; ACE2 receptor), inhibitors of viral and cellular proteases, and immunomodulatory drugs (antagonists of pro-inf l ammatory cytokines or complement components). Novel agents against SARS-CoV-2 are also sought among the previously routinely used drugs as their repositioning and among plant-derived compounds. It is expected that ongoing research should result in the introduction of new drugs used in COVID-19 in the near future. The article brief l y describes the current epidemiological situation regarding COVID-19 and the currently used vaccines. Moreover, the paper outlines currently used and researched potential drugs in the pharmacotherapy of this disease.

The Promising Potential of Reverse Vaccinology-Based Next-Generation Vaccine Development over Conventional Vaccines against Antibiotic-Resistant Bacteria

The clinical use of antibiotics has led to the emergence of multidrug-resistant (MDR) bacteria, leading to the current antibiotic resistance crisis. To address this issue, next-generation vaccines are being developed to prevent antimicrobial resistance caused by MDR bacteria. Traditional vaccine platforms, such as inactivated vaccines (IVs) and live attenuated vaccines (LAVs), were effective in preventing bacterial infections. However, they have shown reduced efficacy against emerging antibiotic-resistant bacteria, including MDR M. tuberculosis. Additionally, the large-scale production of LAVs and IVs requires the growth of live pathogenic microorganisms. A more promising approach for the accelerated development of vaccines against antibiotic-resistant bacteria involves the use of in silico immunoinformatics techniques and reverse vaccinology. The bioinformatics approach can identify highly conserved antigenic targets capable of providing broader protection against emerging drug-resistant bacteria. Multi-epitope vaccines, such as recombinant protein-, DNA-, or mRNA-based vaccines, which incorporate several antigenic targets, offer the potential for accelerated development timelines. This review evaluates the potential of next-generation vaccine development based on the reverse vaccinology approach and highlights the development of safe and immunogenic vaccines through relevant examples from successful preclinical and clinical studies.

Have mRNA vaccines sentenced DNA vaccines to death?

INTRODUCTION

After receiving emergency approval during the COVID-19 pandemic, mRNA vaccines have taken center stage in the quest to enhance future vaccination strategies for both infectious diseases and cancer. Indeed, they have significantly overshadowed another facet of genetic vaccination, specifically DNA vaccines. Nevertheless, it is important to acknowledge that both types of genetic vaccines have distinct advantages and disadvantages that set them apart from each other.

AREAS COVERED

In this work, we delve extensively into the history of genetic vaccines, their mechanisms of action, their strengths, and limitations, and ultimately highlight ongoing research in key areas for potential enhancement of both DNA and mRNA vaccines.

EXPERT OPINION

Here, we assess the significance of the primary benefits and drawbacks associated with DNA and mRNA vaccination. We challenge the current lines of thought by highlighting that the existing drawbacks of DNA vaccination could potentially be more straightforward to address compared to those linked with mRNA vaccination. In our view, this suggests that DNA vaccines should remain viable contenders in the pursuit of the future of vaccination.