Potential adjuvants for the development of a SARS-CoV-2 vaccine based on experimental results from similar coronaviruses

Harnessing Cellular Immunity for Vaccination against Respiratory Viruses

Severe respiratory viral infections, such as influenza, metapneumovirus (HMPV), respiratory syncytial virus (RSV), rhinovirus (RV), and coronaviruses, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), cause significant mortality and morbidity worldwide. These viruses have been identified as important causative agents of acute respiratory disease in infants, the elderly, and immunocompromised individuals. Clinical signs of infection range from mild upper respiratory illness to more serious lower respiratory illness, including bronchiolitis and pneumonia. Additionally, these illnesses can have long-lasting impact on patient health well beyond resolution of the viral infection. Aside from influenza, there are currently no licensed vaccines against these viruses. However, several research groups have tested various vaccine candidates, including those that utilize attenuated virus, virus-like particles (VLPs), protein subunits, and nanoparticles, as well as recent RNA vaccines, with several of these approaches showing promise. Historically, vaccine candidates have advanced, dependent upon the ability to activate the humoral immune response, specifically leading to strong B cell responses and neutralizing antibody production. More recently, it has been recognized that the cellular immune response is also critical in proper resolution of viral infection and protection against detrimental immunopathology associated with severe disease and therefore, must also be considered when analyzing the efficacy and safety of vaccine candidates. These candidates would ideally result in robust CD4+ and CD8+ T cell responses as well as high-affinity neutralizing antibody. This review will aim to summarize established and new approaches that are being examined to harness the cellular immune response during respiratory viral vaccination.

Interpretative immune targets and contemporary position for vaccine development against SARS-CoV-2: A systematic review

The year 2020 started with the emergence of novel coronavirus, severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), which causes COVID‐19 infection. Soon after the first evidence was reported in Wuhan, China, the World Health Organization declared global public health emergency and imminent need to understand the pathogenicity of the virus was required in limited time. Once the genome sequence of the virus was delineated, scientists across the world started working on the development of vaccines. Although, some laboratories have been using previously developed vaccine platforms from severe acute respiratory syndrome coronavirus (SARS) and middle east respiratory syndrome‐related coronavirus and apply them in COVID‐19 vaccines due to genetic similarities between coronaviruses. We have conducted a literature review to assess the background and current status of COVID‐19 vaccines. The worldwide implementation and strategies for COVID‐19 vaccine development are summarized from studies reported in years 2015–2020. While discussing the vaccine candidates, we have also explained interpretative immune responses of SARS‐CoV‐2 infection. There are several vaccine candidates at preclinical and clinical stages; however, only 42 vaccines are under clinical trials. Therefore, more industry collaborations and financial supports to COVID‐19 studies are needed for mass‐scale vaccine development. To develop effective vaccine platforms against SARS‐CoV‐2, the genetic resemblance with other coronaviruses are being evaluated which may further promote fast‐track trials on previously developed SARS‐CoV vaccines.

Bee Venom-A Potential Complementary Medicine Candidate for SARS-CoV-2 Infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by severe cytokine storm syndrome following inflammation. SARS-CoV-2 directly interacts with angiotensin-converting enzyme 2 (ACE-2) receptors in the human body. Complementary therapies that impact on expression of IgE and IgG antibodies, including administration of bee venom (BV), have efficacy in the management of arthritis, and Parkinson's disease. A recent epidemiological study in China showed that local beekeepers have a level of immunity against SARS-CoV-2 with and without previous exposure to virus. BV anti-inflammatory properties are associated with melittin and phospholipase A2 (PLA2), both of which show activity against enveloped and non-enveloped viruses, including H1N1 and HIV, with activity mediated through antagonist activity against interleukin-6 (IL-6), IL-8, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α). Melittin is associated with the underexpression of proinflammatory cytokines, including nuclear factor-kappa B (NF-κB), extracellular signal-regulated kinases (ERK1/2), and protein kinase Akt. BV therapy also involves group III secretory phospholipase A₂ in the management of respiratory and neurological diseases. BV activation of the cellular and humoral immune systems should be explored for the application of complementary medicine for the management of SARS-CoV-2 infections. BV "vaccination" is used to immunize against cytomegalovirus and can suppress metastases through the PLA2 and phosphatidylinositol-(3,4)-bisphosphate pathways. That BV shows efficacy for HIV and H1NI offers opportunity as a candidate for complementary therapy for protection against SARS-CoV-2.

Efforts at COVID-19 Vaccine Development: Challenges and Successes

The rapid spread of SARS-CoV-2, the new coronavirus (CoV), throughout the globe poses a daunting public health emergency. Different preventive efforts have been undertaken in response to this global health predicament; amongst them, vaccine development is at the forefront. Several sophisticated designs have been applied to create a vaccine against SARS-CoV-2, and 44 candidates have already entered clinical trials. At present, it is unclear which ones will meet the objectives of efficiency and safety, though several vaccines are gearing up to obtain emergency approval in the U.S. and Europe. This manuscript discusses the advantages and disadvantages of various vaccine platforms and evaluates the safety and efficacy of vaccines in advance stages. Once a vaccine is developed, the next challenge will be acquisition, deployment, and uptake. The present manuscript describes these challenges in detail and proposes solutions to the vast array of translational challenges. It is evident from the epidemiology of SARS-CoV-2 that the virus will remain a threat to everybody as long as the virus is still circulating in a few. We need affordable vaccines that are produced in sufficient quantity for use in every corner of the world.

The Perspective on Bio-Nano Interface Technology for Covid-19

The field of bio-nano interfaces paves the way for a better understanding, development, and implementation of the advanced biotechnological process. Interfacing biomolecules with the nanomaterials will result in the development of new tools and techniques that, in turn, will enable to explore the fundamental process at the nano level and fabricate cost-effective portable devices. Fascinating biomolecules like DNA, RNA and proteins in the regime of nanoscale are intelligent materials that are capable of storing the information and controlling the basic structure and function of the complex biological systems. Following this concept, the current pandemic situation would be a natural selection process, where the selective pressure is on the ssRNA of Covid-19 to choose the suitable progeny for survival. Consequently, the interaction of human DNA invoking response with Covid-19 happens at the nanoscale and it could be a better candidate to provoke combat against the virus. The extent of this interaction would give us the insights at the nanotechnological level to tackle the prevention, diagnosis and treatment for Covid-19. Herein, the possible features and obstacles in Covid-19 and a probable solution from the advent of nanotechnology are discussed to address the current necessity. Moreover, the perspective sustainable green graph mask that can be prepared using green plant extract/graphene (Bio-Nano composite mask) is suggested for the possible protection of virus-like Covid-19. The composite material will not only effectively trap the virus but also inactivate the virus due to the presence of antiviral compounds in the plant extracts.

COVID-19 and Hyperimmune sera: A feasible plan B to fight against coronavirus

Since the very beginning of the COVID-19 pandemic, different treatment strategies have been explored. These mainly involve the development of antimicrobial, antiviral, and/or anti-inflammatory agents as well as vaccine production. However, other potential options should be more avidly investigated since vaccine production on a worldwide level, and the anti-vaccination movement, also known as anti-vax or vaccine hesitancy by many communities, are still real obstacles without a ready solution. This review presents recent findings on the potential therapeutic advantages of heterologous serotherapy for the treatment of COVID-19. We present not only the effective use in animal models of hyperimmune sera against this coronavirus but also strategies, and protocols for the production of anti-SARS-CoV-2 sera. Promising antigens are also indicated such as the receptor-binding domain (RBD) in SARS-CoV-2 S protein, which is already in phase 2/3 clinical trial, and the trimeric protein S, which was shown to be up to 150 times more potent than the serum from convalescent donors. Due to the high death rate, the treatment for those currently infected with coronavirus cannot be ignored. Therefore, the potential use of anti-SARS-CoV-2 hyperimmune sera should be carefully but urgently evaluated in phase 2/3 clinical studies.

Overview of the current promising approaches for the development of an effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine

Coronavirus disease 2019 (COVID-19) is a pandemic infectious disease caused by the novel coronavirus called SARS-CoV-2. There is a gap in our understanding regarding the immunopathogenesis of COVID-19. However, many clinical trials are underway across the world for screening effective drugs against COVID-19. Nevertheless, currently, no proven effective therapies for this virus exists. The vaccines are deemed as a significant part of disease prevention for emerging viral diseases, since, in several cases, other therapeutic choices are limited or non-existent, or that diseases result in such an accelerated clinical worsening that the efficacy of treatments is restricted. Therefore, effective vaccines against COVID-19 are urgently required to overcome the tremendous burden of mortality and morbidity correlated with SARS-CoV-2. In this review, we will describe the latest evidence regarding outstanding vaccine approaches and the challenges for vaccine production.

CoVaccine HT™ Adjuvant Potentiates Robust Immune Responses to Recombinant SARS-CoV-2 Spike S1 Immunization

The current COVID-19 pandemic has claimed hundreds of thousands of lives and its causative agent, SARS-CoV-2, has infected millions, globally. The highly contagious nature of this respiratory virus has spurred massive global efforts to develop vaccines at record speeds. In addition to enhanced immunogen delivery, adjuvants may greatly impact protective efficacy of a SARS-CoV-2 vaccine. To investigate adjuvant suitability, we formulated protein subunit vaccines consisting of the recombinant S1 domain of SARS-CoV-2 Spike protein alone or in combination with either CoVaccine HT™ or Alhydrogel. CoVaccine HT™ induced high titres of antigen-binding IgG after a single dose, facilitated affinity maturation and class switching to a greater extent than Alhydrogel and elicited potent cell-mediated immunity as well as virus neutralizing antibody titres. Data presented here suggests that adjuvantation with CoVaccine HT™ can rapidly induce a comprehensive and protective immune response to SARS-CoV-2.

Why and How Vaccines Work

Vaccines save millions of lives from infectious diseases caused by viruses and bacteria. As the world awaits safe and effective COVID-19 vaccines, we celebrate the progresses made and highlight challenges ahead in vaccines and the science behind them.

Progress and Pitfalls in the Quest for Effective SARS-CoV-2 (COVID-19) Vaccines

There are currently around 200 SARS-CoV-2 candidate vaccines in preclinical and clinical trials throughout the world. The various candidates employ a range of vaccine strategies including some novel approaches. Currently, the goal is to prove that they are safe and immunogenic in humans (phase 1/2 studies) with several now advancing into phase 2 and 3 trials to demonstrate efficacy and gather comprehensive data on safety. It is highly likely that many vaccines will be shown to stimulate antibody and T cell responses in healthy individuals and have an acceptable safety profile, but the key will be to confirm that they protect against COVID-19. There is much hope that SARS-CoV-2 vaccines will be rolled out to the entire world to contain the pandemic and avert its most damaging impacts. However, in all likelihood this will initially require a targeted approach toward key vulnerable groups. Collaborative efforts are underway to ensure manufacturing can occur at the unprecedented scale and speed required to immunize billions of people. Ensuring deployment also occurs equitably across the globe will be critical. Careful evaluation and ongoing surveillance for safety will be required to address theoretical concerns regarding immune enhancement seen in previous contexts. Herein, we review the current knowledge about the immune response to this novel virus as it pertains to the design of effective and safe SARS-CoV-2 vaccines and the range of novel and established approaches to vaccine development being taken. We provide details of some of the frontrunner vaccines and discuss potential issues including adverse effects, scale-up and delivery.

Current Clinical Trials Protocols and the Global Effort for Immunization against SARS-CoV-2

Coronavirus disease 2019 (COVID-19) is the biggest health challenge of the 21st century, affecting millions of people globally. The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has ignited an unprecedented effort from the scientific community in the development of new vaccines on different platforms due to the absence of a broad and effective treatment for COVID-19 or prevention strategy for SARS-CoV-2 dissemination. Based on 50 current studies selected from the main clinical trial databases, this systematic review summarizes the global race for vaccine development against COVID-19. For each study, the main intervention characteristics, the design used, and the local or global center partnerships created are highlighted. Most vaccine developments have taken place in Asia, using a viral vector method. Two purified inactivated SARS-CoV-2 vaccine candidates, an mRNA-based vaccine mRNA1273, and the chimpanzee adenoviral vaccine ChAdOx1 are currently in phase III clinical trials in the respective countries Brazil, the United Arab Emirates, the USA, and the United Kingdom. These vaccines are being developed based on a quickly formed network of collaboration.

CoVaccine HT™ adjuvant potentiates robust immune responses to recombinant SARS-CoV-2 Spike S1 immunisation

The current COVID-19 pandemic has claimed hundreds of thousands of lives and its causative agent, SARS-CoV-2, has infected millions, globally. The highly contagious nature of this respiratory virus has spurred massive global efforts to develop vaccines at record speeds. In addition to enhanced immunogen delivery, adjuvants may greatly impact protective efficacy of a SARS-CoV-2 vaccine. To investigate adjuvant suitability, we formulated protein subunit vaccines consisting of the recombinant S1 domain of SARS-CoV-2 Spike protein alone or in combination with either CoVaccine HT™ or Alhydrogel. CoVaccine HT™ induced high titres of antigen-binding IgG after a single dose, facilitated affinity maturation and class switching to a greater extent than Alhydrogel and elicited potent cell-mediated immunity as well as virus neutralising antibody titres. Data presented here suggests that adjuvantation with CoVaccine HT™ can rapidly induce a comprehensive and protective immune response to SARS-CoV-2.