Toward Developing a Preventive MERS-CoV Vaccine-Report from a Workshop Organized by the Saudi Arabia Ministry of Health and the International Vaccine Institute, Riyadh, Saudi Arabia, November 14-15, 2015

Identifying the Anti-MERS-CoV and Anti-HcoV-229E Potential Drugs from the Ginkgo biloba Leaves Extract and Its Eco-Friendly Synthesis of Silver Nanoparticles

The present study aimed to estimate the antiviral activities of Ginkgo biloba (GB) leaves extract and eco-friendly free silver nanoparticles (Ag NPs) against the MERS-CoV (Middle East respiratory syndrome-coronavirus) and HCoV-229E (human coronavirus 229E), as well as isolation and identification of phytochemicals from GB. Different solvents and high-performance liquid chromatography (HPLC) were used to extract and identify flavonoids and phenolic compounds from GB leaves. The green, silver nanoparticle synthesis was synthesized from GB leaves aqueous extract and investigated for their possible effects as anti-coronaviruses MERS-CoV and HCoV-229E using MTT assay protocol. To verify the synthesis of Ag NPs, several techniques were employed, including X-ray diffraction (XRD), scan, transmission electron microscopy, FT-IR, and UV-visible spectroscopy. The highest contents of flavonoids and phenolic compounds were recorded for acetone, methanol, and ethanol as mixtures with water, in addition to pure water. HPLC flavonoids were detected as apegenin, luteolin, myricetin, and catechin, while HPLC phenolic compounds were pyrogallol, caffeic acid, gallic acid, and ellagic acid. In addition, our results revealed that Ag NPs were produced through the shift from yellow to dark brown. TEM examination of Ag NPs revealed spherical nanoparticles with mean sizes ranging from 5.46 to 19.40 nm and an average particle diameter of 11.81 nm. A UV-visible spectrophotometric investigation revealed an absorption peak at λ max of 441.56 nm. MTT protocol signified the use of GB leaves extract as an anti-coronavirus to be best from Ag NPs because GB extract had moderate anti-MERS-CoV with SI = 8.94, while had promising anti-HCov-229E, with an SI of 21.71. On the other hand, Ag NPs had a mild anti-MERS-CoV with SI = 4.23, and a moderate anti-HCoV-229E, with an SI of 7.51.

Use of Nanomaterials for Diagnosis and Treatment: The Advancement of Next-Generation Antiviral Therapy

Globally, viral illness propagation is the leading cause of morbidity and death, causing wreaking havoc on socioeconomic development and health care systems. The rise of infected individuals has outpaced the existing critical care facilities. Early and sophisticated methods are desperately required in this respect to halt the spread of the infection. Therefore, early detection of infectious agents and an early treatment approach may help minimize viral outbreaks. Conventional point-of-care diagnostic techniques such as computed tomography scan, quantitative real time polymerase chain reaction (qRT-PCR), X-ray, and immunoassay are still deemed valuable. However, the labor demanding, low sensitivity, and complex infrastructure needed for these methods preclude their use in distant areas. Nanotechnology has emerged as a potentially transformative technology due to its promise as an effective theranostic platform for diagnosing and treating viral infection, circumventing the limits of traditional techniques. Their unique physical and chemical characteristics make nanoparticles (NPs) advantageous for drug delivery platforms due to their size, encapsulation efficiency, improved bioavailability, effectiveness, immunogenicity, and antiviral response. This study discusses the recent research on nanotechnology-based treatments designed to combat new viruses.

SARS-CoV-2 reinfection and implications for vaccine development

Coronavirus disease 2019 (COVID-19) pandemic continues to constitute a public health emergency of international concern. Multiple vaccine candidates for COVID-19, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have entered clinical trials. However, some evidence suggests that patients who have recovered from COVID-19 can be reinfected. For example, in China, two discharged COVID-19 patients who had recovered and fulfilled the discharge criteria for COVID-19 were retested positive to a reverse transcription polymerase chain reaction (RT-PCR) assay for the virus. This finding is critical and could hamper COVID-19 vaccine development. This review offers literature-based evidence of reinfection with SARS-CoV-2, provides explanation for the possibility of SARS-CoV-2 reinfection both from the agent and host points of view, and discusses its implication for COVID-19 vaccine development.

Recent updates on COVID-19: A holistic review

Coronaviruses are large positive-sense RNA viruses with spike-like peplomers on their surface. The Coronaviridae family's strains infect different animals and are popularly associated with several outbreaks, namely SARS and MERS epidemic. COVID-19 is one such recent outbreak caused by SARS-CoV-2 identified first in Wuhan, China. COVID-19 was declared a pandemic by WHO on 11th March 2020. Our review provides information covering various facets of the disease starting from its origin, transmission, mutations in the virus to pathophysiological changes in the host upon infection followed by diagnostics and possible therapeutics available to tackle the situation. We have highlighted the zoonotic origin of SARS-CoV-2, known to share 96.2% nucleotide similarity with bat coronavirus. Notably, several mutations in SARS-CoV-2 spike protein, nucleocapsid protein, PLpro, and ORF3a are reported across the globe. These mutations could alter the usual receptor binding function, fusion process with the host cell, virus replication, and the virus's assembly. Therefore, studying these mutations could help understand the virus's virulence properties and design suitable therapeutics. Moreover, the aggravated immune response to COVID-19 can be fatal. Hypertension, diabetes, and cardiovascular diseases are comorbidities substantially associated with SARS-CoV-2 infection. The review article discusses these aspects, stating the importance of various comorbidities in disease outcomes. Furthermore, medications' unavailability compels the clinicians to opt for atypical drugs like remdesivir, chloroquine, etc. The current diagnostics of COVID-19 include qRT-PCR, CT scan, serological tests, etc. We have described these aspects to expose the information to the scientific community and to accelerate the research.

Vaccines based on virus-like nano-particles for use against Middle East Respiratory Syndrome (MERS) coronavirus

Recent advances in virus-like nanoparticles against Middle East respiratory syndrome-related coronavirus (MERS-CoV) can initiate vaccine production faster for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), while ensuring the safety, easy administration, and long-term effects. Patients with this viral pathogen suffer from excess mortality. MERS-CoV can spread through bioaerosol transmission from animal or human sources. The appearance of an outbreak in South Korea sparked off a strong urge to design strategies for developing an effective vaccine since the emergence of MERS-CoV in 2012. Well unfortunately, this is an important fact in virus risk management. The studies showed that virus-like nanoparticles (VLPs) could be effective in its goal of stopping the symptoms of MERS-CoV infection. Besides, due to the genetic similarities in the DNA sequencing of SARS-CoV-2 with MERS-CoV and the first identified severe acute respiratory syndrome (SARS-CoV) in China since 2002/2003, strategic approaches could be used to manage SARS-CoV 2. Gathering the vital piece of information obtained so far could lead to a breakthrough in the development of an effective vaccine against SARS-CoV-2, which is prioritized and focussed by the World Health Organization (WHO). This review focuses on the virus-like nanoparticle that got successful results in animal models of MERS-CoV.

Mapping COVID-19 related research from Saudi Arabia, a scoping review. Between reality and dreams

OBJECTIVES

To map research production by Saudi-affiliated investigators in order to identify areas of strength and weakness. Method: We followed the Arksey and O'Malley (2005) framework. Medline and Cochrane databases were searched with a focus on identifying articles related to COVID-19 and Saudi Arabia following the PRISMA protocol. The study was conducted at King Saud University, Riyadh, Saudi Arabia between March and May 2020. Results: A total of 53 articles were ultimately included. Most of the research production from Saudi Arabia was opinion and narrative reviews related to the clinicopathological features of COVID-19 as well as control and prevention of virus spread.  Conclusion: The results of this scoping review identify a relative deficiency in original research, which requires further investigation.

Antibody-mediated protection against MERS-CoV in the murine model

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A novel dual route vaccination using the MERS-CoV RBD sub-unit has been developed.

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Murine antisera induced to the RBD protein , were neutralising in vitro.

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MERS-CoV susceptibility was induced in naïve mice with Ad5hDPP4.

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Passive transfer of anti-RBD sera protected susceptible mice.

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Protected mice had a significantly reduced viral titre (P = 0.02) in their lungs.

Murine antisera with neutralising activity for the coronavirus causative of Middle East respiratory syndrome (MERS) were induced by immunisation of Balb/c mice with the receptor binding domain (RBD) of the viral Spike protein. The murine antisera induced were fully-neutralising in vitro for two separate clinical strains of the MERS coronavirus (MERS-CoV). To test the neutralising capacity of these antisera in vivo, susceptibility to MERS-CoV was induced in naive recipient Balb/c mice by the administration of an adenovirus vector expressing the human DPP4 receptor (Ad5-hDPP4) for MERS-CoV, prior to the passive transfer of the RBD-specific murine antisera to the transduced mice. Subsequent challenge of the recipient transduced mice by the intra-nasal route with a clinical isolate of the MERS-CoV resulted in a significantly reduced viral load in their lungs, compared with transduced mice receiving a negative control antibody. The murine antisera used were derived from mice which had been primed sub-cutaneously with a recombinant fusion of RBD with a human IgG Fc tag (RBD-Fc), adsorbed to calcium phosphate microcrystals and then boosted by the oral route with the same fusion protein in reverse micelles. The data gained indicate that this dual-route vaccination with novel formulations of the RBD-Fc, induced systemic and mucosal anti-viral immunity with demonstrated in vitro and in vivo neutralisation capacity for clinical strains of MERS-CoV.

Middle East respiratory syndrome coronavirus (MERS-CoV): A review

As a novel coronavirus first reported by Saudi Arabia in 2012, the Middle East respiratory syndrome coronavirus (MERS-CoV) is responsible for an acute human respiratory syndrome. The virus, of 2C beta-CoV lineage, expresses the dipeptidyl peptidase 4 (DPP4) receptor and is densely endemic in dromedary camels of East Africa and the Arabian Peninsula. MERS-CoV is zoonotic but human-to-human transmission is also possible. Surveillance and phylogenetic researches indicate MERS-CoV to be closely associated with bats' coronaviruses, suggesting bats as reservoirs, although unconfirmed. With no vaccine currently available for MERS-CoV nor approved prophylactics, its global spread to over 25 countries with high fatalities highlights its role as ongoing public health threat. An articulated action plan ought to be taken, preferably from a One Health perspective, for appropriately advanced countermeasures against MERS-CoV.

MERS: Progress on the global response, remaining challenges and the way forward

This article summarizes progress in research on Middle East Respiratory Syndrome (MERS) since a FAO-OIE-WHO Global Technical Meeting held at WHO Headquarters in Geneva on 25-27 September 2017. The meeting reviewed the latest scientific findings and identified and prioritized the global activities necessary to prevent, manage and control the disease. Critical needs for research and technical guidance identified during the meeting have been used to update the WHO R&D MERS-CoV Roadmap for diagnostics, therapeutics and vaccines and a broader public health research agenda. Since the 2017 meeting, progress has been made on several key actions in animal populations, at the animal/human interface and in human populations. This report also summarizes the latest scientific studies on MERS since 2017, including data from more than 50 research studies examining the presence of MERS-CoV infection in dromedary camels.

Chimpanzee adenoviral vectors as vaccines for outbreak pathogens

The 2014-15 Ebola outbreak in West Africa highlighted the potential for large disease outbreaks caused by emerging pathogens and has generated considerable focus on preparedness for future epidemics. Here we discuss drivers, strategies and practical considerations for developing vaccines against outbreak pathogens. Chimpanzee adenoviral (ChAd) vectors have been developed as vaccine candidates for multiple infectious diseases and prostate cancer. ChAd vectors are safe and induce antigen-specific cellular and humoral immunity in all age groups, as well as circumventing the problem of pre-existing immunity encountered with human Ad vectors. For these reasons, such viral vectors provide an attractive platform for stockpiling vaccines for emergency deployment in response to a threatened outbreak of an emerging pathogen. Work is already underway to develop vaccines against a number of other outbreak pathogens and we will also review progress on these approaches here, particularly for Lassa fever, Nipah and MERS.

Development of Middle East Respiratory Syndrome Coronavirus vaccines - advances and challenges

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging pathogen with the potential to pose a threat to global public health. Sporadic cases and outbreaks continue to be reported in the Middle East, and case fatality rates remain high at approximately 36% globally. No specific preventive or therapeutic countermeasures currently exist. A safe and effective vaccine could play an important role in protecting against the threat from MERS-CoV. This review discusses human vaccine candidates currently under development, and explores viral characteristics, molecular epidemiology and immunology relevant to MERS-CoV vaccine development. At present, a DNA vaccine candidate has begun a human clinical trial, while two vector-based candidates will very soon begin human trials. Protein-based vaccines are still at pre-clinical stage. Challenges to successful development include incomplete understanding of viral transmission, pathogenesis and immune response (in particular at the mucosal level), no optimal animal challenge models, lack of standardized immunological assays, and insufficient sustainable funding.

Structural insights into the Middle East respiratory syndrome coronavirus 4a protein and its dsRNA binding mechanism

Middle East respiratory syndrome coronavirus (MERS-CoV) has evolved to navigate through the sophisticated network of a host's immune system. The immune evasion mechanism including type 1 interferon and protein kinase R-mediated antiviral stress responses has been recently attributed to the involvement of MERS-CoV protein 4a (p4a) that masks the viral dsRNA. However, the structural mechanism of how p4a recognizes and establishes contacts with dsRNA is not well explained. In this study, we report a dynamic mechanism deployed by p4a to engage the viral dsRNA and make it unavailable to the host immune system. Multiple variants of p4a-dsRNA were created and investigated through extensive molecular dynamics procedures to highlight crucial interfacial residues that may be used as potential pharmacophores for future drug development. The structural analysis revealed that p4a exhibits a typical αβββα fold structure, as found in other dsRNA-binding proteins. The α1 helix and the β1-β2 loop play a crucial role in recognizing and establishing contacts with the minor grooves of dsRNA. Further, mutational and binding free energy analyses suggested that in addition to K63 and K67, two other residues, K27 and W45, might also be crucial for p4a-dsRNA stability.

New episode of Middle East Respiratory Syndrome Coronavirus outbreak in Saudi Arabia: an emerging public health threat

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Middle East respiratory syndrome coronavirus (MERS-CoV) is resurgent in Saudi Arabia.

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Intercontinental travel facilitates the spread of MERS-CoV infection to other global locations.

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Improved vigilance is imperative to curb the dissemination of infection.

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Discovery of an effective therapy and prophylaxis is a public health priority.

A review of candidate therapies for Middle East respiratory syndrome from a molecular perspective

There have been 2040 laboratory-confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV) in 27 countries, with a mortality rate of 34.9 %. There is no specific therapy. The current therapies have mainly been adapted from severe acute respiratory syndrome (SARS-CoV) treatments, including broad-spectrum antibiotics, corticosteroids, interferons, ribavirin, lopinavir–ritonavir or mycophenolate mofetil, and have not been subject to well-organized clinical trials. The development of specific therapies and vaccines is therefore urgently required. We examine existing and potential therapies and vaccines from a molecular perspective. These include viral S protein targeting; inhibitors of host proteases, including TMPRSS2, cathepsin L and furin protease, and of viral M(pro) and the PL(pro) proteases; convalescent plasma; and vaccine candidates. The Medline database was searched using combinations and variations of terms, including ‘Middle East respiratory syndrome coronavirus’, ‘MERS-CoV’, ‘SARS’, ‘therapy’, ‘molecular’, ‘vaccine’, ‘prophylactic’, ‘S protein’, ‘DPP4’, ‘heptad repeat’, ‘protease’, ‘inhibitor’, ‘anti-viral’, ‘broad-spectrum’, ‘interferon’, ‘convalescent plasma’, ‘lopinavir ritonavir’, ‘antibodies’, ‘antiviral peptides’ and ‘live attenuated viruses’. There are many options for the development of MERS-CoV-specific therapies. Currently, MERS-CoV is not considered to have pandemic potential. However, the high mortality rate and potential for mutations that could increase transmissibility give urgency to the search for direct, effective therapies. Well-designed and controlled clinical trials are needed, both for existing therapies and for prospective direct therapies.

Vaccines for emerging infectious diseases: Lessons from MERS coronavirus and Zika virus

The past decade and a half has been characterized by numerous emerging infectious diseases. With each new threat, there has been a call for rapid vaccine development. Pathogens such as the Middle East Respiratory Syndrome coronavirus (MERS-CoV) and the Zika virus represent either new viral entities or viruses emergent in new geographic locales and characterized by novel complications. Both serve as paradigms for the global spread that can accompany new pathogens. In this paper, we review the epidemiology and pathogenesis of MERS-CoV and Zika virus with respect to vaccine development. The challenges in vaccine development and the approach to clinical trial design to test vaccine candidates for disease entities with a changing epidemiology are discussed.

Middle East respiratory syndrome coronavirus: five years later

INTRODUCTION

In the past five years, there have been 1,936 laboratory-confirmed cases of Middle East Respiratory Syndrome coronavirus (MERS-CoV) in 27 countries, with a mortality rate of 35.6%. Most cases have arisen in the Middle East, particularly the Kingdom of Saudi Arabia, however there was a large hospital-associated outbreak in the Republic of Korea in 2015. Exposure to dromedary camels has been recognized by the World Health Organization (WHO) as a risk factor in primary cases, but the exact mechanisms of transmission are not clear. Rigorous application of nationally defined infection prevention and control measures has reduced the levels of healthcare facility-associated outbreaks. There is currently no approved specific therapy or vaccine available. Areas covered: This review presents an overview of MERS-CoV within the last five years, with a particular emphasis on the key areas of transmission, infection control and prevention, and therapies and vaccines. Expert commentary: MERS-CoV remains a significant threat to public health as transmission mechanisms are still not completely understood. There is the potential for mutations that could increase viral transmission and/or virulence, and zoonotic host range. The high mortality rate highlights the need to expedite well-designed randomized clinical trials for direct, effective therapies and vaccines.

Vaccines for epidemic infections and the role of CEPI

The author reviews the foundation of the Coalition for Epidemic Preparedness and Innovations and the choices it has made for funding of vaccine development against epidemic diseases. He comments on those decisions as well as proposing how CEPI could remain relevant for the long term.

MERS-CoV spike nanoparticles protect mice from MERS-CoV infection

The Middle East respiratory syndrome coronavirus (MERS-CoV) was first discovered in late 2012 and has gone on to cause over 1800 infections and 650 deaths. There are currently no approved therapeutics or vaccinations for MERS-CoV. The MERS-CoV spike (S) protein is responsible for receptor binding and virion entry to cells, is immunodominant and induces neutralizing antibodies in vivo, all of which, make the S protein an ideal target for anti-MERS-CoV vaccines. In this study, we demonstrate protection induced by vaccination with a recombinant MERS-CoV S nanoparticle vaccine and Matrix-M1 adjuvant combination in mice. The MERS-CoV S nanoparticle vaccine produced high titer anti-S neutralizing antibody and protected mice from MERS-CoV infection in vivo.

Progress of Middle East respiratory syndrome coronavirus vaccines: a patent review

INTRODUCTION

Middle East respiratory syndrome coronavirus (MERS-CoV) has emerged as a new pathogen, causing severe complications and a high case fatality rate. No direct treatments are available as yet, highlighting the importance of prevention through suitable vaccination regimes. The viral spike (S) protein has been characterized as a key target antigen for vaccines. In particular, S protein domains have been utilized to produce high titers of neutralizing antibodies. Areas covered: Since the first report of MERS-CoV infection, a limited number of MERS-CoV-specific patents have been filed. Patents related to MERS-CoV are categorized into three areas: treatments, antibodies, and vaccines (receptor-related). This review mainly focuses on the types and efficacies of vaccines, briefly covering treatments and antibodies against the virus. MERS-CoV vaccine forms and delivery systems, together with comparable development strategies against SARS-CoV are additionally addressed. Expert opinion: Vaccines must be combined with delivery systems, administration routes, and adjuvants to maximize T-cell responses as well as neutralizing antibody production. High immune responses require further study in animal models, such as human receptor-expressing mice, non-human primates, and camels. Such a consideration of integrated actions should contribute to the rapid development of vaccines against MERS-CoV and related coronaviruses.

Development of Recombinant Measles Virus-Based Vaccines

This chapter describes the development of recombinant measles virus (MV)-based vaccines starting from plasmid DNA. Live-attenuated measles vaccines are very efficient and safe. Since the availability of a reverse genetic system to manipulate MV genomes and to generate respective recombinant viruses, a considerable number of recombinant viruses has been generated that present antigens of foreign pathogens during MV replication. Thereby, robust humoral and cellular immune responses can be induced, which have shown protective capacity in a substantial number of experiments.For this purpose, the foreign antigen-encoding genes are cloned into additional transcription units of plasmid based full-length MV vaccine strain genomes, which in turn are used to rescue recombinant MV by providing both full-length viral RNA genomes respective anti-genomes together with all protein components of the viral ribonucleoprotein complex after transient transfection of the so-called rescue cells. Infectious centers form among these transfected cells, which allow clonal isolation of single recombinant viruses that are subsequently amplified, characterized in vitro, and then evaluated for their immunogenicity in appropriate preclinical animal models.