Replicating Viral Vector-Based Vaccines for COVID-19: Potential Avenue in Vaccination Arena

Vaccine skepticism and vaccine development stages; inoculation from "cowpox" lesion to the current mRNA vaccine of COVID-19: review

Global pandemics can be tackled by two means: lockdowns and vaccinations. As vaccination has a low impact on economic outcomes and better acceptance by people, it is the preferred method by most governments as a medium- to long-term solution. Vaccines have played a significant role in reducing the global burden of infectious diseases. They are designed to teach the immune system how to fight a particular infection before it causes a disease in subsequent exposures by creating a memory. Although vaccines effectiveness is well known, anti-vaccination movements pose significant challenges, even in high-income settings, leading to outbreaks of life-threatening infectious diseases. Hesitancy to take vaccines is not new and began with the first vaccination of smallpox. At that time, the problem was solved by a regulatory obligation to take vaccines, declared in England and Wales in 1853, which eventually led to its eradication in 1980. Different studies show that there is a decline in awareness of vaccines, hesitancy to take them, and concerns and trust issues regarding healthcare professionals. These problems have been rising over the past few decades for several reasons, notably, because of misinformation spread by social media. Therefore, the objective of this review is to provide a brief overview about vaccine hesitancy and attributable factors, illustrate the different types of vaccines, show the major challenges of vaccine development, and illustrate the pros and cons of each type.

SARS-CoV-2 Neutralization Assays Used in Clinical Trials: A Narrative Review

Since the emergence of COVID-19, extensive research efforts have been undertaken to accelerate the development of multiple types of vaccines to combat the pandemic. These include inactivated, recombinant subunit, viral vector, and nucleic acid vaccines. In the development of these diverse vaccines, appropriate methods to assess vaccine immunogenicity are essential in both preclinical and clinical studies. Among the biomarkers used in vaccine evaluation, the neutralizing antibody level serves as a pivotal indicator for assessing vaccine efficacy. Neutralizing antibody detection methods can mainly be classified into three types: the conventional virus neutralization test, pseudovirus neutralization test, and surrogate virus neutralization test. Importantly, standardization of these assays is critical for their application to yield results that are comparable across different laboratories. The development and use of international or regional standards would facilitate assay standardization and facilitate comparisons of the immune responses induced by different vaccines. In this comprehensive review, we discuss the principles, advantages, limitations, and application of different SARS-CoV-2 neutralization assays in vaccine clinical trials. This will provide guidance for the development and evaluation of COVID-19 vaccines.

How do we change our approach to COVID with the changing face of disease?

INTRODUCTION

The emergence of SARS-CoV-2 triggered a global health emergency, causing > 7 million deaths thus far. Limited early knowledge spurred swift research, treatment, and vaccine developments. Implementation of public health measures such as, lockdowns and social distancing, disrupted economies and strained healthcare. Viral mutations highlighted the need for flexible strategies and strong public health infrastructure, with global collaboration crucial for pandemic control.

AREAS COVERED

(i) Revisiting diagnostic strategies, (ii) adapting to the evolving challenge of the virus, (iii) vaccines against new variants, (iv) vaccine hesitancy in the light of the evolving disease, (v) treatment strategies, (vi) hospital preparedness for changing clinical needs, (vii) global cooperation and data sharing, (viii) economic implications, and (ix) education and awareness- keeping communities informed.

EXPERT OPINION

The COVID-19 crisis forced unprecedented adaptation, emphasizing public health readiness, global unity, and scientific advancement. Key lessons highlight the importance of adaptability and resilience against uncertainties. As the pandemic evolves into a 'new normal,' ongoing vigilance, improved understanding, and available vaccines and treatments equip us for future challenges. Priorities now include proactive pandemic strategies, early warnings, supported healthcare, public education, and addressing societal disparities for better health resilience and sustainability.

High-titer manufacturing of SARS-CoV-2 Spike-pseudotyped VSV in stirred-tank bioreactors

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic highlighted the importance of vaccine innovation in public health. Hundreds of vaccines built on numerous technology platforms have been rapidly developed against SARS-CoV-2 since 2020. Like all vaccine platforms, an important bottleneck to viral-vectored vaccine development is manufacturing. Here, we describe a scalable manufacturing protocol for replication-competent SARS-CoV-2 Spike-pseudotyped vesicular stomatitis virus (S-VSV)-vectored vaccines using Vero cells grown on microcarriers in a stirred-tank bioreactor. Using Cytodex 1 microcarriers over 6 days of fed-batch culture, Vero cells grew to a density of 3.95 ± 0.42 ×106 cells/mL in 1-L stirred-tank bioreactors. Ancestral strain S-VSV reached a peak titer of 2.05 ± 0.58 ×108 plaque-forming units (PFUs)/mL at 3 days postinfection. When compared to growth in plate-based cultures, this was a 29-fold increase in virus production, meaning a 1-L bioreactor produces the same amount of virus as 1,284 plates of 15 cm. In addition, the omicron BA.1 S-VSV reached a peak titer of 5.58 ± 0.35 × 106 PFU/mL. Quality control testing showed plate- and bioreactor-produced S-VSV had similar particle-to-PFU ratios and elicited comparable levels of neutralizing antibodies in immunized hamsters. This method should enhance preclinical and clinical development of pseudotyped VSV-vectored vaccines in future pandemics.

Protein subunit vaccines: Promising frontiers against COVID-19

The emergence of COVID-19 has posed an unprecedented global health crisis, challenging the healthcare systems worldwide. Amidst the rapid development of several vaccine formulations, protein subunit vaccines have emerged as a promising approach. This article provides an in-depth evaluation of the role of protein subunit vaccines in the management of COVID-19. Leveraging viral protein fragments, particularly the spike protein from SARS-CoV-2, these vaccines elicit a targeted immune response without the risk of inducing disease. Notably, the robust safety profile of protein subunit vaccines makes them a compelling candidate in the management of COVID-19. Various innovative approaches, including reverse vaccinology, virus like particles, and recombinant modifications are incorporated to develop protein subunit vaccines. In addition, the utilization of advanced manufacturing techniques facilitates large-scale production, ensuring widespread distribution. Despite these advancements, challenges persist, such as the requirement for cold-chain storage and the necessity for booster doses. This article evaluates the formulation and applications of protein subunit vaccines, providing a comprehensive overview of their clinical development and approvals in the context of COVID-19. By addressing the current status and challenges, this review aims to contribute to the ongoing discourse on optimizing protein subunit vaccines for effective pandemic control.

A T cell-targeted multi-antigen vaccine generates robust cellular and humoral immunity against SARS-CoV-2 infection

SARS-CoV-2, the etiological agent behind the coronavirus disease 2019 (COVID-19) pandemic, has continued to mutate and create new variants with increased resistance against the WHO-approved spike-based vaccines. With a significant portion of the worldwide population still unvaccinated and with waning immunity against newly emerging variants, there is a pressing need to develop novel vaccines that provide broader and longer-lasting protection. To generate broader protective immunity against COVID-19, we developed our second-generation vaccinia virus-based COVID-19 vaccine, TOH-VAC-2, encoded with modified versions of the spike (S) and nucleocapsid (N) proteins as well as a unique poly-epitope antigen that contains immunodominant T cell epitopes from seven different SARS-CoV-2 proteins. We show that the poly-epitope antigen restimulates T cells from the PBMCs of individuals formerly infected with SARS-CoV-2. In mice, TOH-VAC-2 vaccination produces high titers of S- and N-specific antibodies and generates robust T cell immunity against S, N, and poly-epitope antigens. The immunity generated from TOH-VAC-2 is also capable of protecting mice from heterologous challenge with recombinant VSV viruses that express the same SARS-CoV-2 antigens. Altogether, these findings demonstrate the effectiveness of our versatile vaccine platform as an alternative or complementary approach to current vaccines.

COVID-19 vaccine triggered autoimmune hepatitis: case report

Autoimmune hepatitis (AIH) is a non-contagious, chronic, inflammatory autoimmune disease in which one's own immune system attacks healthy, normal hepatic cells. The exact cause of AIH is unknown; however, the combination of genetic, environmental (eg, drugs and natural infection) and immunological factors may lead to AIH. AIH may also be potentiated with the use of vaccines: this case reports one such event following immunisation, along with 1 year of follow-up. A female patient in her late 20s presented to the hospital with yellowish discolouration of eyes, urine and stools. Her medical history revealed that she had been vaccinated with the first dose of a COVID-19 vaccine 10 days earlier. She had a history of asymptomatic COVID-19 infection 3 months ago and a history of chronic analgesic consumption for migraine. She was diagnosed as having AIH through extensive clinical and laboratory workup. This case may be an immediate enhancement of a hidden autoimmune disorder triggered by the vaccination. This adverse event following immunisation has an adequate temporal relationship with her COVID-19 vaccine. The causality can be categorised as 'indeterminate' and may be considered as a potential signal following COVID-19 vaccination.

COVID-19 Vaccines over Three Years after the Outbreak of the COVID-19 Epidemic

The outbreak of COVID-19 started in December 2019 and spread rapidly all over the world. It became clear that the development of an effective vaccine was the only way to stop the pandemic. It was the first time in the history of infectious diseases that the process of the development of a new vaccine was conducted on such a large scale and accelerated so rapidly. At the end of 2020, the first COVID-19 vaccines were approved for marketing. At the end of March 2023, over three years after the outbreak of the COVID-19 pandemic, 199 vaccines were in pre-clinical development and 183 in clinical development. The candidate vaccines in the clinical phase are based on the following platforms: protein subunit, DNA, RNA, non-replication viral vector, replicating viral vector, inactivated virus, virus-like particles, live attenuated virus, replicating viral vector combined with an antigen-presenting cell, non-replication viral vector combined with an antigen-presenting cell, and bacterial antigen-spore expression vector. Some of the new vaccine platforms have been approved for the first time for human application. This review presents COVID-19 vaccines currently available in the world, procedures for assurance of the quality and safety of the vaccines, the vaccinated population, as well as future perspectives for the new vaccine platforms in drug and therapy development for infectious and non-infectious diseases.

Exigency of Plant-Based Vaccine against COVID-19 Emergence as Pandemic Preparedness

After two years since the declaration of COVID-19 as a pandemic by the World Health Organization (WHO), more than six million deaths have occurred due to SARS-CoV-2, leading to an unprecedented disruption of the global economy. Fortunately, within a year, a wide range of vaccines, including pathogen-based inactivated and live-attenuated vaccines, replicating and non-replicating vector-based vaccines, nucleic acid (DNA and mRNA)-based vaccines, and protein-based subunit and virus-like particle (VLP)-based vaccines, have been developed to mitigate the severe impacts of the COVID-19 pandemic. These vaccines have proven highly effective in reducing the severity of illness and preventing deaths. However, the availability and supply of COVID-19 vaccines have become an issue due to the prioritization of vaccine distribution in most countries. Additionally, as the virus continues to mutate and spread, questions have arisen regarding the effectiveness of vaccines against new strains of SARS-CoV-2 that can evade host immunity. The urgent need for booster doses to enhance immunity has been recognized. The scarcity of "safe and effective" vaccines has exacerbated global inequalities in terms of vaccine coverage. The development of COVID-19 vaccines has fallen short of the expectations set forth in 2020 and 2021. Furthermore, the equitable distribution of vaccines at the global and national levels remains a challenge, particularly in developing countries. In such circumstances, the exigency of plant virus-based vaccines has become apparent as a means to overcome supply shortages through fast manufacturing processes and to enable quick and convenient distribution to millions of people without the reliance on a cold chain system. Moreover, plant virus-based vaccines have demonstrated both safety and efficacy in eliciting robust cellular immunogenicity against COVID-19 pathogens. This review aims to shed light on the advantages and disadvantages of different types of vaccines developed against SARS-CoV-2 and provide an update on the current status of plant-based vaccines in the fight against the COVID-19 pandemic.

Non-Invasive Vaccines: Challenges in Formulation and Vaccine Adjuvants

Given the limitations of conventional invasive vaccines, such as the requirement for a cold chain system and trained personnel, needle-based injuries, and limited immunogenicity, non-invasive vaccines have gained significant attention. Although numerous approaches for formulating and administrating non-invasive vaccines have emerged, each of them faces its own challenges associated with vaccine bioavailability, toxicity, and other issues. To overcome such limitations, researchers have created novel supplementary materials and delivery systems. The goal of this review article is to provide vaccine formulation researchers with the most up-to-date information on vaccine formulation and the immunological mechanisms available, to identify the technical challenges associated with the commercialization of non-invasive vaccines, and to guide future research and development efforts.

mRNA-Based Vaccine for COVID-19: They Are New but Not Unknown!

mRNA vaccines take advantage of the mechanism that our cells use to produce proteins. Our cells produce proteins based on the knowledge contained in our DNA; each gene encodes a unique protein. The genetic information is essential, but cells cannot use it until mRNA molecules convert it into instructions for producing specific proteins. mRNA vaccinations provide ready-to-use mRNA instructions for constructing a specific protein. BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) both are newly approved mRNA-based COVID-19 vaccines that have shown excellent protection and efficacy. In total, there are five more mRNA-based vaccine candidates for COVID-19 under different phases of clinical development. This review is specifically focused on mRNA-based vaccines for COVID-19 covering its development, mechanism, and clinical aspects.

Adenoviral Vector-Based Vaccine Platform for COVID-19: Current Status

The coronavirus disease (COVID-19) breakout had an unimaginable worldwide effect in the 21st century, claiming millions of lives and putting a huge burden on the global economy. The potential developments in vaccine technologies following the determination of the genetic sequence of SARS-CoV-2 and the increasing global efforts to bring potential vaccines and therapeutics into the market for emergency use have provided a small bright spot to this tragic event. Several intriguing vaccine candidates have been developed using recombinant technology, genetic engineering, and other vaccine development technologies. In the last decade, a vast amount of the vaccine development process has diversified towards the usage of viral vector-based vaccines. The immune response elicited by such vaccines is comparatively higher than other approved vaccine candidates that require a booster dose to provide sufficient immune protection. The non-replicating adenoviral vectors are promising vaccine carriers for infectious diseases due to better yield, cGMP-friendly manufacturing processes, safety, better efficacy, manageable shipping, and storage procedures. As of April 2022, the WHO has approved a total of 10 vaccines around the world for COVID-19 (33 vaccines approved by at least one country), among which three candidates are adenoviral vector-based vaccines. This review sheds light on the developmental summary of all the adenoviral vector-based vaccines that are under emergency use authorization (EUA) or in the different stages of development for COVID-19 management.

Conventional and Novel Diagnostic Tools for the Diagnosis of Emerging SARS-CoV-2 Variants

Accurate identification at an early stage of infection is critical for effective care of any infectious disease. The "coronavirus disease 2019 (COVID-19)" outbreak, caused by the virus "Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)", corresponds to the current and global pandemic, characterized by several developing variants, many of which are classified as variants of concern (VOCs) by the "World Health Organization (WHO, Geneva, Switzerland)". The primary diagnosis of infection is made using either the molecular technique of RT-PCR, which detects parts of the viral genome's RNA, or immunodiagnostic procedures, which identify viral proteins or antibodies generated by the host. As the demand for the RT-PCR test grew fast, several inexperienced producers joined the market with innovative kits, and an increasing number of laboratories joined the diagnostic field, rendering the test results increasingly prone to mistakes. It is difficult to determine how the outcomes of one unnoticed result could influence decisions about patient quarantine and social isolation, particularly when the patients themselves are health care providers. The development of point-of-care testing helps in the rapid in-field diagnosis of the disease, and such testing can also be used as a bedside monitor for mapping the progression of the disease in critical patients. In this review, we have provided the readers with available molecular diagnostic techniques and their pitfalls in detecting emerging VOCs of SARS-CoV-2, and lastly, we have discussed AI-ML- and nanotechnology-based smart diagnostic techniques for SARS-CoV-2 detection.

Precision-engineering of subunit vaccine particles for prevention of infectious diseases

Vaccines remain the best approach for the prevention of infectious diseases. Protein subunit vaccines are safe compared to live-attenuated whole cell vaccines but often show reduced immunogenicity. Subunit vaccines in particulate format show improved vaccine efficacy by inducing strong immune responses leading to protective immunity against the respective pathogens. Antigens with proper conformation and function are often required to induce functional immune responses. Production of such antigens requiring post-translational modifications and/or composed of multiple complex domains in bacterial hosts remains challenging. Here, we discuss strategies to overcome these limitations toward the development of particulate vaccines eliciting desired humoral and cellular immune responses. We also describe innovative concepts of assembling particulate vaccine candidates with complex antigens bearing multiple post-translational modifications. The approaches include non-covalent attachments (e.g. biotin-avidin affinity) and covalent attachments (e.g. SpyCatcher-SpyTag) to attach post-translationally modified antigens to particles.

Effect of COVID-19 (SARS-CoV-2) Vaccination on Patients with Atopic Dermatitis Treated with Dupilumab: A Multicenter, Observational Study

BACKGROUND

Atopic dermatitis (AD) patients usually wonder if their condition will worsen after vaccination or if they should continue with the treatment they are receiving. Considering that many patients treated with dupilumab had previously experienced severe AD symptoms and flares, the concerns are more understandable.

OBJECTIVE

This study aimed to investigate the safety of the coronavirus disease 2019 (COVID-19) vaccination in patients with AD treated with dupilumab.

METHODS

We enrolled 133 patients (101 dupilumab-treated and 32 systemic oral agents-treated as control group) with AD from six hospitals. Patients were asked about worsening pruritus and AD (5-point Likert scale) after vaccination. AD variables (eczema area and severity index [EASI], investigator's global assessment [IGA], itch numerical rating scale [NRS], sleep NRS, and patient-oriented eczema measure [POEM]) were compared pre- and post-vaccination. Adverse reactions to the COVID-19 vaccination were observed.

RESULTS

The incidence of adverse reactions to COVID-19 vaccines and worsening AD symptoms in dupilumab-treated patients were not significantly different compared with that in the control group. The itch NRS score increased significantly after vaccination (p<0.001). However, there were no statistically significant differences between the pre-and post-EASI, IGA, and POEM scores. Eight patients (7.9%) had worse EASI scores and required rescue therapy; however, most were easily managed with low-dose steroids or topical agents. None of the patients discontinued dupilumab treatment.

CONCLUSION

No serious adverse reactions were observed in patients with AD after COVID-19 vaccination. Exacerbation of pruritus and AD symptoms was observed but was mostly mild and transient.

The Global Impact of COVID-19: Historical Development, Molecular Characterization, Drug Discovery and Future Directions

In December 2019, an outbreak of a respiratory disease called the coronavirus disease 2019 (COVID-19) caused by a new coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in Wuhan, China. The SARS-CoV-2, an encapsulated positive-stranded RNA virus, spread worldwide with disastrous consequences for people's health, economies, and quality of life. The disease has had far-reaching impacts on society, including economic disruption, school closures, and increased stress and anxiety. It has also highlighted disparities in healthcare access and outcomes, with marginalized communities disproportionately affected by the SARS-CoV-2. The symptoms of COVID-19 range from mild to severe. There is presently no effective cure. Nevertheless, significant progress has been made in developing COVID-19 vaccine for different therapeutic targets. For instance, scientists developed multifold vaccine candidates shortly after the COVID-19 outbreak after Pfizer and AstraZeneca discovered the initial COVID-19 vaccines. These vaccines reduce disease spread, severity, and mortality. The addition of rapid diagnostics to microscopy for COVID-19 diagnosis has proven crucial. Our review provides a thorough overview of the historical development of COVID-19 and molecular and biochemical characterization of the SARS-CoV-2. We highlight the potential contributions from insect and plant sources as anti-SARS-CoV-2 and present directions for future research.

mRNA-Based Vaccines and Therapeutics for COVID-19 and Future Pandemics

An unheard mobilization of resources to find SARS-CoV-2 vaccines and therapies has been sparked by the COVID-19 pandemic. Two years ago, COVID-19's launch propelled mRNA-based technologies into the public eye. Knowledge gained from mRNA technology used to combat COVID-19 is assisting in the creation of treatments and vaccines to treat existing illnesses and may avert pandemics in the future. Exploiting the capacity of mRNA to create therapeutic proteins to impede or treat a variety of illnesses, including cancer, is the main goal of the quickly developing, highly multidisciplinary field of biomedicine. In this review, we explore the potential of mRNA as a vaccine and therapeutic using current research findings.

Smart Nanostructured Materials for SARS-CoV-2 and Variants Prevention, Biosensing and Vaccination

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has raised great concerns about human health globally. At the current stage, prevention and vaccination are still the most efficient ways to slow down the pandemic and to treat SARS-CoV-2 in various aspects. In this review, we summarize current progress and research activities in developing smart nanostructured materials for COVID-19 prevention, sensing, and vaccination. A few established concepts to prevent the spreading of SARS-CoV-2 and the variants of concerns (VOCs) are firstly reviewed, which emphasizes the importance of smart nanostructures in cutting the virus spreading chains. In the second part, we focus our discussion on the development of stimuli-responsive nanostructures for high-performance biosensing and detection of SARS-CoV-2 and VOCs. The use of nanostructures in developing effective and reliable vaccines for SARS-CoV-2 and VOCs will be introduced in the following section. In the conclusion, we summarize the current research focus on smart nanostructured materials for SARS-CoV-2 treatment. Some existing challenges are also provided, which need continuous efforts in creating smart nanostructured materials for coronavirus biosensing, treatment, and vaccination.

An Impact of COVID-19 on Cancer Care: An Update

The world has been affected socioeconomically for the last two years due to the emergence of different variants of the COVID-19 virus. Vaccination is the major and most efficient way to prevent the widening of this pandemic. Those who are having comorbidities are more vulnerable to serious infections due to their immunocompromised state. Additionally, cancer patients could be at significant risk for COVID-19. In this pandemic era, the diagnosis and treatment of cancer were significantly affected. Clinical trials at the initial stage were performed on healthy or COVID-19 infected patients. This produces a greater level of hesitancy in cancer patients. This review article provide an update regarding the vaccination and treatment for COVID-19 in patients with cancer and future directions.

Nitric Oxide and its Derivatives Containing Nasal Spray and Inhalation Therapy for the Treatment of COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a major health concern worldwide and has evolved into different variants. SARS-CoV-2 possesses a spike glycoprotein on its envelope that binds to the angiotensin-converting enzyme 2 (ACE-2) receptor of the host cell via the receptor-binding domain (RBD) in the upper respiratory tract. Since the SARS-CoV-2 virus variants change the severity of the diesease and treatment scenarios, repurposing current medicines may provide a quick and appealing method with established safety features. The efficacy and safety of antiviral medicines against the coronavirus disease 2019 (COVID-19) have been investigated, and several of them are now undergoing clinical studies. Recently, it has been found that nitric oxide (NO) shows antiviral properties against SARS-CoV-2 and prevents the virus from binding to a host cell. In addition, NO is a well-known vasodilator and acts as an important coagulation mediator. With the fast-track development of COVID-19 treatments and vaccines, one avenue of research aimed at improving therapeutics is exploring different forms of drug delivery, including intranasal sprays and inhalation therapy. The nasal mucosa is more prone to be the site of infection as it is in more direct contact with the physical environment via air during inhalation and exhalation. Thus, the use of exogenous nasal NO therapy via the intranasal route displays a distinct advantage. Therefore, the objective of this review is to summarize the relevant actions of NO via the intranasal spray and inhalation delivery, its mechanism of action, and its use in the treatment of COVID-19.

Variant influenza: connecting the missing dots

BACKGROUND

In June 2009, the World Health Organization declared a new pandemic, the 2009 swine influenza pandemic (swine flu). The symptoms of the swine flu pandemic causing strain were comparable to most of the symptoms noted by seasonal influenza.

AREA COVERED

Zoonotic viruses that caused the swine flu pandemic and its preventive measures.

EXPERT OPINION

As per Centers for Disease Control and Prevention (CDC), the clinical manifestations in humans produced by the 2009 H1N1 'swine flu' virus were equivalent to the manifestations caused by related flu strains. The H1N1 vaccination was the most successful prophylactic measure since it prevented the virus from spreading and reduced the intensity and consequences of the pandemic. Despite the availability of therapeutics, the ongoing evolution and appearance of new strains have made it difficult to develop effective vaccines and therapies. Currently, the CDC recommends yearly flu immunization for those aged 6 months and above. The lessons learned from the A/2009/H1N1 pandemic in 2009 indicated that readiness of mankind toward new illnesses caused by mutant viral subtypes that leap from animals to people must be maintained.

Recent review of COVID-19 management: diagnosis, treatment and vaccination

The idiopathic Coronavirus disease 2019 (COVID-19) pandemic outbreak caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has reached global proportions; the World Health Organization (WHO) declared it as a public health emergency during the month of January 30, 2020. The major causes of the rise of new variants of SARS-CoV-2 are genetic mutations and recombination. Some of the variants with high infection and transmission rates are termed as variants of concern (VOCs) like currently Omicron variants. Pregnant women, aged people, and immunosuppressed and compromised patients constitute the most susceptible human population to the SARS-CoV-2 infection, especially to the new evolving VOCs. To effectively manage the pathological condition of infection, the focus should be directed towards prevention and prophylactic approach. In this narrative review, we aimed to analyze the current scenario of COVID-19 management and discuss the treatment and prevention strategies. We also focused on the complications prevalent during the COVID-19 and post-COVID period and to discuss the novel approaches developed for mitigation of the global pandemic. We have also emphasized on the COVID-19 management approaches for the special population including children, pregnant women, aged groups, and immunocompromised patients. We conclude that the advancements in therapeutic and pharmacological domains have provided opportunities to develop and design novel diagnosis, treatment, and prevention strategies. New advanced techniques such as RT-LAMP, RT-qPCR, High-Resolution Computed Tomography, etc., efficiently diagnose patients with SARS-CoV-2 infection. In the case of treatment options, new drugs like paxlovid, combinations of β-lactum drugs and molnupiravir are found to be effective against even the new emerging variants. In addition, vaccination is an essential approach to prevent the infection or to reduce its severity. Vaccines for against COVID-19 from Comirnaty by Pfizer-BioNTech, SpikeVax by Moderna, and Vaxzevria by Oxford-AstraZeneca are approved and used widely. Similarly, numerous vaccines have been developed with different percentages of effectiveness against VOCs. New developments like nanotechnology and AI can be beneficial in providing an efficient and reliable solution for the suppression of SARS-CoV-2. Public health concerns can be efficiently treated by a unified scientific approach, public engagement, and better diagnosis.

Host Protective Immunity against Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) and the COVID-19 Vaccine-Induced Immunity against SARS-CoV-2 and Its Variants

The world is now apparently at the last/recovery stage of the COVID-19 pandemic, starting from 29 December 2019, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). With the progression of time, several mutations have taken place in the original SARS-CoV-2 Wuhan strain, which have generated variants of concern (VOC). Therefore, combatting COVID-19 has required the development of COVID-19 vaccines using several platforms. The immunity induced by those vaccines is vital to study in order to assure total protection against SARS-CoV-2 and its emerging variants. Indeed, understanding and identifying COVID-19 protection mechanisms or the host immune responses are of significance in terms of designing both new and repurposed drugs as well as the development of novel vaccines with few to no side effects. Detecting the immune mechanisms for host protection against SARS-CoV-2 and its variants is crucial for the development of novel COVID-19 vaccines as well as to monitor the effectiveness of the currently used vaccines worldwide. Immune memory in terms of the production of neutralizing antibodies (NAbs) during reinfection is also very crucial to formulate the vaccine administration schedule/vaccine doses. The response of antigen-specific antibodies and NAbs as well as T cell responses, along with the protective cytokine production and the innate immunity generated upon COVID-19 vaccination, are discussed in the current review in comparison to the features of naturally induced protective immunity.

The Delta and Omicron Variants of SARS-CoV-2: What We Know So Far

The world has not yet completely overcome the fear of the havoc brought by SARS-CoV-2. The virus has undergone several mutations since its initial appearance in China in December 2019. Several variations (i.e., B.1.616.1 (Kappa variant), B.1.617.2 (Delta variant), B.1.617.3, and BA.2.75 (Omicron variant)) have emerged throughout the pandemic, altering the virus's capacity to spread, risk profile, and even symptoms. Humanity faces a serious threat as long as the virus keeps adapting and changing its fundamental function to evade the immune system. The Delta variant has two escape alterations, E484Q and L452R, as well as other mutations; the most notable of these is P681R, which is expected to boost infectivity, whereas the Omicron has about 60 mutations with certain deletions and insertions. The Delta variant is 40-60% more contagious in comparison to the Alpha variant. Additionally, the AY.1 lineage, also known as the "Delta plus" variant, surfaced as a result of a mutation in the Delta variant, which was one of the causes of the life-threatening second wave of coronavirus disease 2019 (COVID-19). Nevertheless, the recent Omicron variants represent a reminder that the COVID-19 epidemic is far from ending. The wave has sparked a fervor of investigation on why the variant initially appeared to propagate so much more rapidly than the other three variants of concerns (VOCs), whether it is more threatening in those other ways, and how its type of mutations, which induce minor changes in its proteins, can wreck trouble. This review sheds light on the pathogenicity, mutations, treatments, and impact on the vaccine efficacy of the Delta and Omicron variants of SARS-CoV-2.

Fast-track development of vaccines for SARS-CoV-2: The shots that saved the world

In December 2019, an outbreak emerged of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which leads to coronavirus disease 2019 (COVID-19). The World Health Organisation announced the outbreak a global health emergency on 30 January 2020 and by 11 March 2020 it was declared a pandemic. The spread and severity of the outbreak took a heavy toll and overburdening of the global health system, particularly since there were no available drugs against SARS-CoV-2. With an immediate worldwide effort, communication, and sharing of data, large amounts of funding, researchers and pharmaceutical companies immediately fast-tracked vaccine development in order to prevent severe disease, hospitalizations and death. A number of vaccines were quickly approved for emergency use, and worldwide vaccination rollouts were immediately put in place. However, due to several individuals being hesitant to vaccinations and many poorer countries not having access to vaccines, multiple SARS-CoV-2 variants quickly emerged that were distinct from the original variant. Uncertainties related to the effectiveness of the various vaccines against the new variants as well as vaccine specific-side effects have remained a concern. Despite these uncertainties, fast-track vaccine approval, manufacturing at large scale, and the effective distribution of COVID-19 vaccines remain the topmost priorities around the world. Unprecedented efforts made by vaccine developers/researchers as well as healthcare staff, played a major role in distributing vaccine shots that provided protection and/or reduced disease severity, and deaths, even with the delta and omicron variants. Fortunately, even for those who become infected, vaccination appears to protect against major disease, hospitalisation, and fatality from COVID-19. Herein, we analyse ongoing vaccination studies and vaccine platforms that have saved many deaths from the pandemic.

Co-infection associated with SARS-CoV-2 and their management

SARS-CoV-2 was discovered in Wuhan, China and quickly spread throughout the world. This deadly virus moved from person to person, resulting in severe pneumonia, fever, chills and hypoxia. Patients are still experiencing problems after recovering from COVID-19. This review covers COVID-19 and associated issues following recovery from COVID-19, as well as multiorgan damage risk factors and treatment techniques. Several unusual illnesses, including mucormycosis, white fungus infection, happy hypoxia and other systemic abnormalities, have been reported in recovered individuals. In children, multisystem inflammatory syndrome with COVID-19 (MIS-C) is identified. The reasons for this might include uncontrollable steroid usage, reduced immunity, uncontrollable diabetes mellitus and inadequate care following COVID-19 recovery.

A replication-competent smallpox vaccine LC16m8Δ-based COVID-19 vaccine

Viral vectors are a potent vaccine platform for inducing humoral and T-cell immune responses. Among the various viral vectors, replication-competent ones are less commonly used for coronavirus disease 2019 (COVID-19) vaccine development compared with replication-deficient ones. Here, we show the availability of a smallpox vaccine LC16m8Δ (m8Δ) as a replication-competent viral vector for a COVID-19 vaccine. M8Δ is a genetically stable variant of the licensed and highly effective Japanese smallpox vaccine LC16m8. Here, we generated two m8Δ recombinants: one harbouring a gene cassette encoding the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) glycoprotein, named m8Δ-SARS2(P7.5-S)-HA; and one encoding the S protein with a highly polybasic motif at the S1/S2 cleavage site, named m8Δ-SARS2(P7.5-S_HN)-HA. M8Δ-SARS2(P7.5-S)-HA induced S-specific antibodies in mice that persisted for at least six weeks after a homologous boost immunization. All eight analysed serum samples displayed neutralizing activity against an S-pseudotyped virus at a level similar to that of serum samples from patients with COVID-19, and more than half (5/8) also had neutralizing activity against the Delta/B.1.617.2 variant of concern. Importantly, most serum samples also neutralized the infectious SARS-CoV-2 Wuhan and Delta/B.1.617.2 strains. In contrast, immunization with m8Δ-SARS2(P7.5-S_HN)-HA elicited significantly lower antibody titres, and the induced antibodies had less neutralizing activity. Regarding T-cell immunity, both m8Δ recombinants elicited S-specific multifunctional CD8⁺ and CD4⁺ T-cell responses even after just a primary immunization. Thus, m8Δ provides an alternative method for developing a novel COVID-19 vaccine.

Pseudoscience and fraudulent products for COVID-19 management

As of now, the COVID-19 pandemic has become uncontrolled and is spreading widely throughout the world. Additionally, new variants of the mutated viral variants have been found in some countries that are more dangerous than the original strain. Even vaccines cannot produce complete protective immunity against the newer strains of SARS-CoV-2. Due to such a dreadful situation, lots of fear and depression have been created among the public. People are looking for the treatment of the disease at any cost and there is a race in the market to provide treatment and make money, whether it is effective or not! In such a condition, many fraud products, remedies, and myths have come into the market, which is falsely claimed to be effective for the disease and can harm the patients. Hence, FDA has banned such products and remedies. In this review, we have compiled all such fraudulent and pseudosciences identified for COVID-19. Currently, in the pandemic time, health agencies are approving the repurposed medicines based on the small-scale clinical data for emergency uses that become ineffective (most of the cases) after large randomized clinical studies. Proper vigilance strategies need to be defined by the regulatory agencies of the nation and routine awareness programs shall be arranged for educating the people and healthcare workers on routine updates.

Viral vector and nucleic acid vaccines against COVID-19: A narrative review

After about 2 years since the first detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Wuhan, China, in December 2019 that resulted in a worldwide pandemic, 6.2 million deaths have been recorded. As a result, there is an urgent need for the development of a safe and effective vaccine for coronavirus disease 2019 (COVID-19). Endeavors for the production of effective vaccines inexhaustibly are continuing. At present according to the World Health Organization (WHO) COVID-19 vaccine tracker and landscape, 153 vaccine candidates are developing in the clinical phase all over the world. Some new and exciting platforms are nucleic acid-based vaccines such as Pfizer Biontech and Moderna vaccines consisting of a messenger RNA (mRNA) encoding a viral spike protein in host cells. Another novel vaccine platform is viral vector vaccine candidates that could be replicating or nonreplicating. These types of vaccines that have a harmless viral vector like adenovirus contain a genome encoding the spike protein of SARS-CoV-2, which induces significant immune responses. This technology of vaccine manufacturing has previously been used in many human clinical trials conducted for adenoviral vector-based vaccines against different infectious agents, including Ebola virus, Zika virus, HIV, and malaria. In this paper, we have a review of nucleic acid-based vaccines that are passing their phase 3 and 4 clinical trials and discuss their efficiency and adverse effects.

COVID-19 and vaccination: myths vs science

INTRODUCTION

Several vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed since the inception of the coronavirus disease 2019 (COVID-19) in December 2019, at unprecedented speed. However, these rapidly developed vaccines raised many questions related to the efficacy and safety of vaccines in different communities across the globe. Various hypotheses regarding COVID-19 and its vaccines were generated, and many of them have also been answered with scientific evidence. Still, there are many myths/misinformation related to COVID-19 and its vaccines, which create hesitancy for COVID-19 vaccination, and must be addressed critically to achieve success in the battle against the pandemic.

AREA COVERED

The development of anti-SARS-CoV-2 vaccines against COVID-19, their safety and efficacy, and myths/misinformation relating to COVID-19 and vaccines are presented.

EXPERT OPINION

In this pandemic we have seen a global collaborative effort of researchers, governments, and industry, supported by billions of dollars in funding, have allowed the development of vaccines far more quickly than in the past. Vaccines go through rigorous testing, analysis, and evaluations in clinical settings prior to their approval, even if they are approved for emergency use. Despite the myths, vaccination represents an important strategy to get back to normality.

Vaccination efforts for Buruli Ulcer

BACKGROUND

Buruli ulcer is one of the most common mycobacterial diseases usually affecting poorer populations in tropical and subtropical environments. This disease, caused by M. ulcerans infection, has devastating effects for patients, with significant health and economic burden. Antibiotics are often used to treat affected individuals, but in most cases, surgery is necessary.

AREA COVERED

We present progress on Buruli ulcer vaccines and identify knowledge gaps in this neglected tropical disease.

EXPERT OPINION

The lack of appropriate infrastructure in endemic areas, as well as the severity of symptoms and lack of non-invasive treatment options, highlights the need for an effective vaccine to combat this disease. In terms of humoral immunity, it is vital to consider its significance and the magnitude to which it inhibits or slowdowns the progression of the disease. Only by answering these key questions will it be possible to tailor more appropriate vaccination and preventative provisions.

Dendritic cell-based vaccine: the state-of-the-art vaccine platform for COVID-19 management

INTRODUCTION

A correlation between new coronaviruses and host immunity, as well as the role of defective immune function in host response, would be extremely helpful in understanding coronavirus disease (COVID-19) pathogenicity, and a coherent structure of treatments and vaccines. As existing vaccines may be inadequate for new viral variants emerging in various regions of the world, it is a vital requirement for fresh and effective therapeutic alternatives.

AREA COVERED

Immunotherapy may give a viable protective option for COVID-19, a disease that is currently a big burden on global health and economic systems. Herein, we have outlined three dendritic cell (DC)-based vaccines for COVID-19 which are in human clinical trials and have shown encouraging outcomes.

EXPERT OPINION

With existing knowledge of the virus, and the nature of DC, DC-based vaccines may be proven to be effective in inducing long-lasting protective immunity, especially T cell responses.

Therapeutics to tackle Omicron outbreak

Tweetable abstract In this commentary, the authors have focused on the mutational impact of the Omicron variant on the current therapeutics to manage #COVID19.

Aged Population and Immunocompromised Patients: Impact on SARS-CoV-2 Variants and Treatment Outcomes

Patients with an immunocompromised state are at risk of developing a long-term infection from the coronavirus 2 that causes severe acute respiratory syndrome (SARS-CoV-2) [...]

Therapeutic monoclonal antibodies for COVID-19 management: an update

BACKGROUND

The first case of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral disease in the world was announced on 31^st December 2019 in Wuhan, China. Since then, this virus has affected more than 440 million people, and today the world is facing different mutant strains of the virus, leading to increased morbidity rates, fatality rates, and surfacing re-infections. Various therapies, such as prophylactic treatments, repurposed drug treatments, convalescent plasma, and polyclonal antibody therapy have been developed to help combat the coronavirus disease 2019 (COVID-19).

AREA COVERED

This review article provides insights into the basic aspects of monoclonal antibodies (mAbs) for the therapy of COVID-19, as well as its advancement in terms of clinical trial and current approval status.

EXPERT OPINION

Monoclonal antibodies represents the most effective and viable therapy and/or prophylaxis option against COVID-19, and have shown a reduction of the viral load, as well as lowering hospitalizations and death rates. In different countries, various mAbs are undergoing different phases of clinical trials, with a few of them having entered phases III and IV. Due to the soaring number of cases worldwide, the FDA has given emergency approval for the mAb combinations bamlanivimab with etesevimab and casirivimab with imdevimab.