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Thriving Vaccines and Research: Weizmann Institute Coronavirus Research Development

Reporter: Amandeep Kaur, B.Sc., M.Sc.

In early February, Prof. Eran Segal updated in one of his tweets and mentioned that “We say with caution, the magic has started.”

The article reported that this statement by Prof. Segal was due to decreasing cases of COVID-19, severe infection cases and hospitalization of patients by rapid vaccination process throughout Israel. Prof. Segal emphasizes in another tweet to remain cautious over the country and informed that there is a long way to cover and searching for scientific solutions.

A daylong webinar entitled “COVID-19: The epidemic that rattles the world” was a great initiative by Weizmann Institute to share their scientific knowledge about the infection among the Israeli institutions and scientists. Prof. Gideon Schreiber and Dr. Ron Diskin organized the event with the support of the Weizmann Coronavirus Response Fund and Israel Society for Biochemistry and Molecular Biology. The speakers were invited from the Hebrew University of Jerusalem, Tel-Aviv University, the Israel Institute for Biological Research (IIBR), and Kaplan Medical Center who addressed the molecular structure and infection biology of the virus, treatments and medications for COVID-19, and the positive and negative effect of the pandemic.

The article reported that with the emergence of pandemic, the scientists at Weizmann started more than 60 projects to explore the virus from different range of perspectives. With the help of funds raised by communities worldwide for the Weizmann Coronavirus Response Fund supported scientists and investigators to elucidate the chemistry, physics and biology behind SARS-CoV-2 infection.

Prof. Avi Levy, the coordinator of the Weizmann Institute’s coronavirus research efforts, mentioned “The vaccines are here, and they will drastically reduce infection rates. But the coronavirus can mutate, and there are many similar infectious diseases out there to be dealt with. All of this research is critical to understanding all sorts of viruses and to preempting any future pandemics.”

The following are few important projects with recent updates reported in the article.

Mapping a hijacker’s methods

Dr. Noam Stern-Ginossar studied the virus invading strategies into the healthy cells and hijack the cell’s systems to divide and reproduce. The article reported that viruses take over the genetic translation system and mainly the ribosomes to produce viral proteins. Dr. Noam used a novel approach known as ‘ribosome profiling’ as her research objective and create a map to locate the translational events taking place inside the viral genome, which further maps the full repertoire of viral proteins produced inside the host.

She and her team members grouped together with the Weizmann’s de Botton Institute and researchers at IIBR for Protein Profiling and understanding the hijacking instructions of coronavirus and developing tools for treatment and therapies. Scientists generated a high-resolution map of the coding regions in the SARS-CoV-2 genome using ribosome-profiling techniques, which allowed researchers to quantify the expression of vital zones along the virus genome that regulates the translation of viral proteins. The study published in Nature in January, explains the hijacking process and reported that virus produces more instruction in the form of viral mRNA than the host and thus dominates the translation process of the host cell. Researchers also clarified that it is the misconception that virus forced the host cell to translate its viral mRNA more efficiently than the host’s own translation, rather high level of viral translation instructions causes hijacking. This study provides valuable insights for the development of effective vaccines and drugs against the COVID-19 infection.

Like chutzpah, some things don’t translate

Prof. Igor Ulitsky and his team worked on untranslated region of viral genome. The article reported that “Not all the parts of viral transcript is translated into protein- rather play some important role in protein production and infection which is unknown.” This region may affect the molecular environment of the translated zones. The Ulitsky group researched to characterize that how the genetic sequence of regions that do not translate into proteins directly or indirectly affect the stability and efficiency of the translating sequences.

Initially, scientists created the library of about 6,000 regions of untranslated sequences to further study their functions. In collaboration with Dr. Noam Stern-Ginossar’s lab, the researchers of Ulitsky’s team worked on Nsp1 protein and focused on the mechanism that how such regions affect the Nsp1 protein production which in turn enhances the virulence. The researchers generated a new alternative and more authentic protocol after solving some technical difficulties which included infecting cells with variants from initial library. Within few months, the researchers are expecting to obtain a more detailed map of how the stability of Nsp1 protein production is getting affected by specific sequences of the untranslated regions.

The landscape of elimination

The article reported that the body’s immune system consists of two main factors- HLA (Human Leukocyte antigen) molecules and T cells for identifying and fighting infections. HLA molecules are protein molecules present on the cell surface and bring fragments of peptide to the surface from inside the infected cell. These peptide fragments are recognized and destroyed by the T cells of the immune system. Samuels’ group tried to find out the answer to the question that how does the body’s surveillance system recognizes the appropriate peptide derived from virus and destroy it. They isolated and analyzed the ‘HLA peptidome’- the complete set of peptides bound to the HLA proteins from inside the SARS-CoV-2 infected cells.

After the analysis of infected cells, they found 26 class-I and 36 class-II HLA peptides, which are present in 99% of the population around the world. Two peptides from HLA class-I were commonly present on the cell surface and two other peptides were derived from coronavirus rare proteins- which mean that these specific coronavirus peptides were marked for easy detection. Among the identified peptides, two peptides were novel discoveries and seven others were shown to induce an immune response earlier. These results from the study will help to develop new vaccines against new coronavirus mutation variants.

Gearing up ‘chain terminators’ to battle the coronavirus

Prof. Rotem Sorek and his lab discovered a family of enzymes within bacteria that produce novel antiviral molecules. These small molecules manufactured by bacteria act as ‘chain terminators’ to fight against the virus invading the bacteria. The study published in Nature in January which reported that these molecules cause a chemical reaction that halts the virus’s replication ability. These new molecules are modified derivates of nucleotide which integrates at the molecular level in the virus and obstruct the works.

Prof. Sorek and his group hypothesize that these new particles could serve as a potential antiviral drug based on the mechanism of chain termination utilized in antiviral drugs used recently in the clinical treatments. Yeda Research and Development has certified these small novel molecules to a company for testing its antiviral mechanism against SARS-CoV-2 infection. Such novel discoveries provide evidences that bacterial immune system is a potential repository of many natural antiviral particles.

Resolving borderline diagnoses

Currently, Real-time Polymerase chain reaction (RT-PCR) is the only choice and extensively used for diagnosis of COVID-19 patients around the globe. Beside its benefits, there are problems associated with RT-PCR, false negative and false positive results and its limitation in detecting new mutations in the virus and emerging variants in the population worldwide. Prof. Eran Elinavs’ lab and Prof. Ido Amits’ lab are working collaboratively to develop a massively parallel, next-generation sequencing technique that tests more effectively and precisely as compared to RT-PCR. This technique can characterize the emerging mutations in SARS-CoV-2, co-occurring viral, bacterial and fungal infections and response patterns in human.

The scientists identified viral variants and distinctive host signatures that help to differentiate infected individuals from non-infected individuals and patients with mild symptoms and severe symptoms.

In Hadassah-Hebrew University Medical Center, Profs. Elinav and Amit are performing trails of the pipeline to test the accuracy in borderline cases, where RT-PCR shows ambiguous or incorrect results. For proper diagnosis and patient stratification, researchers calibrated their severity-prediction matrix. Collectively, scientists are putting efforts to develop a reliable system that resolves borderline cases of RT-PCR and identify new virus variants with known and new mutations, and uses data from human host to classify patients who are needed of close observation and extensive treatment from those who have mild complications and can be managed conservatively.

Moon shot consortium refining drug options

The ‘Moon shot’ consortium was launched almost a year ago with an initiative to develop a novel antiviral drug against SARS-CoV-2 and was led by Dr. Nir London of the Department of Chemical and Structural Biology at Weizmann, Prof. Frank von Delft of Oxford University and the UK’s Diamond Light Source synchroton facility.

To advance the series of novel molecules from conception to evidence of antiviral activity, the scientists have gathered support, guidance, expertise and resources from researchers around the world within a year. The article reported that researchers have built an alternative template for drug-discovery, full transparency process, which avoids the hindrance of intellectual property and red tape.

The new molecules discovered by scientists inhibit a protease, a SARS-CoV-2 protein playing important role in virus replication. The team collaborated with the Israel Institute of Biological Research and other several labs across the globe to demonstrate the efficacy of molecules not only in-vitro as well as in analysis against live virus.

Further research is performed including assaying of safety and efficacy of these potential drugs in living models. The first trial on mice has been started in March. Beside this, additional drugs are optimized and nominated for preclinical testing as candidate drug.

Source: https://www.weizmann.ac.il/WeizmannCompass/sections/features/the-vaccines-are-here-and-research-abounds

Other related articles were published in this Open Access Online Scientific Journal, including the following:

Identification of Novel genes in human that fight COVID-19 infection

Reporter: Amandeep Kaur, B.Sc., M.Sc. (ept. 5/2021)

https://pharmaceuticalintelligence.com/2021/04/19/identification-of-novel-genes-in-human-that-fight-covid-19-infection/

Fighting Chaos with Care, community trust, engagement must be cornerstones of pandemic response

Reporter: Amandeep Kaur, B.Sc., M.Sc. (ept. 5/2021)

https://pharmaceuticalintelligence.com/2021/04/13/fighting-chaos-with-care/

T cells recognize recent SARS-CoV-2 variants

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2021/03/30/t-cells-recognize-recent-sars-cov-2-variants/

Need for Global Response to SARS-CoV-2 Viral Variants

Reporter: Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2021/02/12/need-for-global-response-to-sars-cov-2-viral-variants/

Mechanistic link between SARS-CoV-2 infection and increased risk of stroke using 3D printed models and human endothelial cells

Reporter: Adina Hazan, PhD

https://pharmaceuticalintelligence.com/2020/12/28/mechanistic-link-between-sars-cov-2-infection-and-increased-risk-of-stroke-using-3d-printed-models-and-human-endothelial-cells/

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COVID-19-vaccine rollout risks and challenges

Reporter : Irina Robu, PhD

BioNTech and Pfizer and Moderna COVID-19 vaccines received Emergency Use Authorization in January 2021 in Canada, European Union, United Kingdom and United States. However, in certain places COVID-19 has hit a few hindrances such as stockpiles have accumulated, deployment to vulnerable countries and at-risk groups has been slower than expected.  Yet, experts can see the light at the end of the tunnel of the pandemic. In United States, hundred of organization take a vital role in vaccine deployment, adapting their operations to meet the demands for volume, speed and better technology. Tens of thousands of transporters, vaccine handlers, medical and pharmacy staff, and frontline workers have mandatory training on the specific characteristics of each manufacturer’s distinct vaccines.

The common operating model provides the details of end-to-end vaccine deployment. Possible areas of risk to the rapid delivery of COVID-19 vaccines in the United States include:

Raw-materials constraints in production scaling

Scaling access to material and boosting production levels can cause logistical, contractual and even diplomatic challenges, requiring new forms of collaboration. The top two US manufacturers, for example, can produce 280 million vials per year, capable of holding up to 2.8 billion doses.

Quality-assurance challenges in manufacturing

Generating yields to produce a new class of vaccines—such as those based on mRNA or viral vectors—at an unprecedented scale (1.8 billion to 2.3 billion doses by mid-2021), manufacturers have required massive volumes of inputs, a larger technical workforce.

Cold-chain logistics and storage-management challenges

Manufacturers and distributors are preparing to maintain cold-chain requirements for distribution and long-term storage of mRNA-based vaccines. Large amounts of dry ice may be needed at various locations before administration.

Increased labor requirements

Complex protocols for handling and preparing COVID-19 vaccines have the potential to strain labor capacities or divert workers from other critical roles.

Wastage at points of care

Errors in storing, preparing, or scheduling administration of doses at points of care will have significant consequences and proper on-site storage conditions are also of critical importance.

IT challenges

IT systems, including vaccine-tracking systems and immunization information systems will be vital for allocating, distributing, recording, and monitoring the deployment of vaccines.

There are several possible approaches to help mitigate each of the six risks discussed, each with practical steps for organization to take across the common operating model.

Building resilient raw-materials supplies

  • Resilience planning.Producers can partner with global suppliers of raw materials and ancillary-product manufacturers to create redundancies.
  • Collaboration between industry and government.Ongoing industry engagement with government is essential for ramping-up production and maintaining high levels of production.

 Scaling manufacturing within quality guidelines

  • Scale manufacturing in new and existing facilities.  Various digital and analytics tools can help expand capacity and scale more quickly.
  • Assure quality and yield in current facilities. By continuing to coordinate with regulators, manufacturers and authorities can certify that procedures and dosage quality meet both long-established and newly issued guidelines.
  • Establish predictable supplier plans. Each manufacturing stakeholder can follow a clearly defined plan and they can also conduct regular cross-functional risk reviews to ensure that quality.

Optimizing the cold chain

  • Build redundancy into distribution.Manufacturers, distributers should quickly identify points of failure and creating redundancies at each stage.
  • Leverage feedback loops.Reporting systems could be set up to capture supply-chain disruption events as soon as they happen, with data used to refine best practices and procedures and avoid further losses.
  • Use point-of-care stock management.Vaccine inventories can be redistributed to locations with greater demand. Strategies to avoid over stockpiling must confirm maintenance of the cold chain to prevent risks to the receiving administration site.

Addressing labor shortages

  • Use several types of point-of-care facilities.Rely on hospitals and primary-care locations for vaccine administration, in addition to retail pharmacies.
  • Streamline administration across sites.Deploying vaccines at larger, streamlined vaccination sites can be more efficient and improve patient safety, labor utilization, and speed of vaccination.

 Reducing spoilage at points of care

  • Track and monitor spoilage at points of care.Manufacturers and distributors can collaborate to establish the means to identify and trace instances of spoilage. They can learn from experience and refine guidance, training, certification, and allocation to optimize utilization of doses.
  • Pace first-dose allocation.Allocation of first doses to populations and locations where the need is greatest and the confidence in the availability of second doses is high (such as healthcare professionals and vulnerable populations in nursing homes).
  • Prioritize second doses.Authorities can help ensure that the recommended two-dose course schedule for such vaccines as the Pfizer-BioNTech, Moderna, and AstraZeneca vaccines are duly completed.
  • Establish recipient commitment.Vaccine recipients could be asked to commit to second-dose appointments at their point of care before first-dose administration.
  • Manage certification.National and local government institutions can collaborate to ensure that vaccination certifications are withheld until recipients receive their second dose.

Meeting IT challenges

  • Balance IT upgrades and resilience.Stakeholders should identify IT systems that can be relied upon in the deployment of COVID-19 vaccines and assess their ability to perform at scale.
  • Share cyberthreat intelligence.COVID-19-vaccine stakeholders should agree upon common requirements and processes for generating and sharing threat intelligence.
  • Establish means of demonstrating immunity.Manufacturers and distributers can commission systems to track and verify that vaccine recipients have demonstrated immunity. if it will release them from travel limits and other pandemic-related restrictions.

Although not one organization is involved for managing vaccine deployment, but the risks can be fully address if organizations align on lead organization to build scenarios to test responses to emerging crises. The groups could align on lead organizations to manage issues while building scenarios to test responses to emerging crises. The benefits in managing each of these risks could be demonstrated with compelling metrics and communications.  As COVID-19-vaccine rollouts commence, the steps mentioned above can be undertaken by manufactures, distributors and governments.

SOURCE

https://www.mckinsey.com/business-functions/risk/our-insights/the-risks-and-challenges-of-the-global-covid-19-vaccine-rollout?cid=other-eml-nsl-mip-mck&hlkid=19a51f848bee4d00806d2da81315f70d&hctky=2071733&hdpid=062f1841-f911-48f3-ab14-a9f92e30721f#

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National Public Radio interview with Dr. Anthony Fauci on his optimism on a COVID-19 vaccine by early 2021

Reporter: Stephen J. Williams, PhD

Below I am giving a link to an important interview by NPR’s Judy Woodruff with Dr. Anthony Fauci on his thoughts regarding the recent spikes in cases, the potential for a COVID-19 vaccine by next year, and promising therapeutics in the pipeline.  The interview link is given below however I will summarize a few of the highlights of the interview.

 

Some notes on the interview

Judy Woodruff began her report with some up to date news regarding the recent spike and that Miami Florida has just ordered the additional use of facemasks.  She asked Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases (NIAD), about if the measures currently in use are enough to bring this spike down.  Dr. Fauci said that we need to reboot our efforts, mainly because people are not doing three things which could have prevented this spike mainly

  1. universal wearing of masks
  2. distancing properly from each other
  3. close the bars and pubs (see Wisconsin bars packed after ruling)

It hasn’t been a uniform personal effort

Dr. Fauci on testing

We have to use the tests we have out there efficiently and effectively And we have to get them out to the right people who can do the proper identification, isolation, and do proper contract tracing and need to test more widely in a surveillance way to get a feel of the extent and penetrance of this community spread.  there needs to be support and money for these testing labs

We have a problem and we need to admit and own it but we need to do the things we know are effective to turn this thing around.

On Vaccines

“May be later this year”

His response to Merck’s CEO Ken Frazer who said officials are giving false hop if they say ‘end of year’ but Dr. Fauci disagrees.  He says a year end goal is not outlandish.

What we have been doing is putting certain things in line with each other in an unprecedented way.

Dr. Fauci went on to say that, in the past yes, it took a long time, even years to develop a vaccine but now they have been able to go from sequence of virus to a vaccine development program in days, which is unheard of.  Sixty two days later we have gone into phase 1 trials. the speed at which this is occurring is so much faster.  He says that generally it would take a couple of years to get a neutralizing antibody but we are already there.  Another candidate will be undergoing phase 3 trials by end of this month (July 2020).

He is “cautiously optimistic” that we will have one or more vaccines to give to patients by end of year because given the amount of cases it will be able to get a handle on safety and efficacy by late fall.

Now he says the game changer is that the government is working with companies to ramp up the production of doses of the candidate vaccines so when we find which one works we will have ample doses on hand.  He is worried about the anti vaccine movement derailing vaccine testing and vaccinations but says if we keep on informing the public we can combat this.

Going back to school

Dr. Fauci is concerned for the safety of the vulnerable in schools, including students and staff.  He wants the US to get down to a reasonable baseline of cases but in the US that baseline after the first wave was still significantly higher than in most countries, where the baseline was more like tens of cases not hundreds of cases.

For more information on COVID-19 Please go to our Coronavirus Portal at

https://pharmaceuticalintelligence.com/coronavirus-portal/

 

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From Cell Press:  New Insights on the D614G Strain of COVID: Will a New Mutated Strain Delay Vaccine Development?

Reporter: Stephen J. Williams, PhD

Two recent articles in Cell Press, both peer reviewed, discuss the emergence and potential dominance of a new mutated strain of COVID-19, in which the spike protein harbors a D614G mutation.

In the first article “Making Sense of Mutation: What D614G means for the COVID-19 pandemic Remains Unclear”[1] , authors Drs. Nathan Grubaugh, William Hanage, and Angela Rasmussen discuss the recent findings by Korber et al. 2020 [2] which describe the potential increases in infectivity and mortality of this new mutant compared to the parent strain of SARS-CoV2.  For completeness sake I will post this article as to not defer from their interpretations of this important paper by Korber and to offer some counter opinion to some articles which have surfaced this morning in the news.

Making sense of mutation: what D614G means for the COVID-19 pandemic remains unclear

 

Nathan D. Grubaugh1 *, William P. Hanage2 *, Angela L. Rasmussen3 * 1Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA 2Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA 3Center for Infection and Immunity, Columbia Mailman School of Public Health, New York, NY 10032, USA Correspondence: grubaughlab@gmail.com

 

Abstract: Korber et al. (2020) found that a SARS-CoV-2 variant in the spike protein, D614G, rapidly became dominant around the world. While clinical and in vitro data suggest that D614G changes the virus phenotype, the impact of the mutation on transmission, disease, and vaccine and therapeutic development are largely unknown.

Introduction: Following the emergence of SARS-CoV-2 in China in late 2019, and the rapid expansion of the COVID19 pandemic in 2020, questions about viral evolution have come tumbling after. Did SARS-CoV-2 evolve to become better adapted to humans? More infectious or transmissible? More deadly? Virus mutations can rise in frequency due to natural selection, random genetic drift, or features of recent epidemiology. As these forces can work in tandem, it’s often hard to differentiate when a virus mutation becomes common through fitness or by chance. It is even harder to determine if a single mutation will change the outcome of an infection, or a pandemic. The new study by Korber et al. (2020) sits at the heart of this debate. They present compelling data that an amino acid change in the virus’ spike protein, D614G, emerged early during the pandemic, and viruses containing G614 are now dominant in many places around the world. The crucial questions are whether this is the result of natural selection, and what it means for the COVID-19 pandemic. For viruses like SARS-CoV-2 transmission really is everything – if they don’t get into another host their lineage ends. Korber et al. (2020) hypothesized that the rapid spread of G614 was because it is more infectious than D614. In support of their hypothesis, the authors provided evidence that clinical samples from G614 infections have a higher levels of viral RNA, and produced higher titers in pseudoviruses from in vitro experiments; results that now seem to be corroborated by others [e.g. (Hu et al., 2020; Wagner et al., 2020)]. Still, these data do not prove that G614 is more infectious or transmissible than viruses containing D614. And because of that, many questions remain on the potential impacts, if any, that D614G has on the COVID-19 pandemic.

The authors note that this new G614 variant has become the predominant form over the whole world however in China the predominant form is still the D614 form.  As they state

“over the period that G614 became the global majority variant, the number of introductions from China where D614 was still dominant were declining, while those from Europe climbed. This alone might explain the apparent success of G614.”

Grubaugh et al. feel there is not enough evidence that infection with this new variant will lead to higher mortality.  Both Korber et al. and the Seattle study (Wagner et al) did not find that the higher viral load of this variant led to a difference in hospitalizations so apparently each variant might be equally as morbid.

In addition, Grubaugh et al. believe this variant would not have much affect on vaccine development as, even though the mutation lies within the spike protein, D614G is not in the receptor binding domain of the spike protein.  Korber suggest that there may be changes in glycosylation however these experiments will need to be performed.  In addition, antibodies from either D614 or G614 variant infected patients could cross neutralize.

 

Conclusions: While there has already been much breathless commentary on what this mutation means for the COVID19 pandemic, the global expansion of G614 whether through natural selection or chance means that this variant now is the pandemic. As a result its properties matter. It is clear from the in vitro and clinical data that G614 has a distinct phenotype, but whether this is the result of bonafide adaptation to human ACE2, whether it increases transmissibility, or will have a notable effect, is not clear. The work by Korber et al. (2020) provides an early base for more extensive epidemiological, in vivo experimental, and diverse clinical investigations to fill in the many critical gaps in how D614G impacts the pandemic.

The link to the Korber Cell paper is here: https://www.cell.com/cell/fulltext/S0092-8674(20)30820-5

Tracking changes in SARS-CoV-2 Spike: evidence that D614G increases infectivity of the COVID-19 virus

DOI: https://doi.org/10.1016/j.cell.2020.06.043

Keypoints

  • The consistent increase of G614 at regional levels may indicate a fitness advantage

 

  • G614 is associated with lower RT PCR Ct’s, suggestive of higher viral loads in patients

 

  • The G614 variant grows to higher titers as pseudotyped virions

Summary

A SARS-CoV-2 variant carrying the Spike protein amino acid change D614G has become the most prevalent form in the global pandemic. Dynamic tracking of variant frequencies revealed a recurrent pattern of G614 increase at multiple geographic levels: national, regional and municipal. The shift occurred even in local epidemics where the original D614 form was well established prior to the introduction of the G614 variant. The consistency of this pattern was highly statistically significant, suggesting that the G614 variant may have a fitness advantage. We found that the G614 variant grows to higher titer as pseudotyped virions. In infected individuals G614 is associated with lower RT-PCR cycle thresholds, suggestive of higher upper respiratory tract viral loads, although not with increased disease severity. These findings illuminate changes important for a mechanistic understanding of the virus, and support continuing surveillance of Spike mutations to aid in the development of immunological interventions.

 

References

  1. Grubaugh, N.D., Hanage, W.P., Rasmussen, A.L., Making sense of mutation: what D614G means for the COVID-19 pandemic remains unclear, Cell (2020), doi: https:// doi.org/10.1016/j.cell.2020.06.040.
  2. Korber, B., Fischer, W.M., Gnanakaran, S., Yoon, H., Theiler, J., Abfalterer, W., Hengartner, N., Giorgi, E.E., Bhattacharya, T., Foley, B., et al. (2020). Tracking changes in SARS-CoV-2 Spike: evidence that D614G increases infectivity of the COVID-19 virus. Cell 182.
  3. Endo, A., Centre for the Mathematical Modelling of Infectious Diseases COVID-19 Working Group, Abbott, S., Kucharski, A.J., and Funk, S. (2020). Estimating the overdispersion in COVID-19 transmission using outbreak sizes outside China. Wellcome Open Res 5, 67.
  4. Hu, J., He, C.-L., Gao, Q.-Z., Zhang, G.-J., Cao, X.-X., Long, Q.-X., Deng, H.-J., Huang, L.-Y., Chen, J., Wang, K., et al. (2020). The D614G mutation of SARS-CoV-2 spike protein enhances viral infectivity and decreases neutralization sensitivity to individual convalescent sera. bioRxiv 2020.06.20.161323.
  5. Wagner, C., Roychoudhury, P., Hadfield, J., Hodcroft, E.B., Lee, J., Moncla, L.H., Müller, N.F., Behrens, C., Huang, M.-L., Mathias, P., et al. (2020). Comparing viral load and clinical outcomes in Washington State across D614G mutation in spike protein of SARS-CoV-2. Https://github.com/blab/ncov-D614G.

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Recombinant Coronavirus Vaccines Delivered via Microneedle Array

Curator: Irina Robu, PhD

Coronavirus is an evolving pathogen with exponentially increasing significance due to the high case fatality rate, the large distribution of reservoir, and the lack of medical countermeasures. The public health emergencies triggered by coronaviruses, including SARS-CoV and SARS-CoV-2, obviously validate the urgency to assess candidate vaccines to fight these outbreaks. Continuous research contributes to the efforts of scientists to quickly progress safe vaccines against these developing infections. The recent COVID-19 pandemic indicates a vital need for the rapid design, production, testing, and clinical translation of candidate vaccines.

Coronavirus virus particles contain four main structural proteins. These are the spike, membrane, envelope, and nucleocapsid proteins, all of which are encoded within the 3′ end of the viral genome. Coronaviruses contain a non-segmented, positive-sense RNA genome, which contains a 5′ cap structure along with a 3′ poly (A) tail, allowing it to act as a mRNA for translation of the replicase polyproteins. The replicase gene encoding the nonstructural proteins inhabits two-thirds of the genome, which make up only about 10 kb of the viral genome. The 5′ end of the genome contains a leader sequence and untranslated region that encompasses multiple stem loop structures required for RNA replication and transcription. Furthermore, at the start of each structural gene are the transcriptional regulatory sequences that are essential for expression of each of these genes.

Researchers at U of Pittsburg generated codon optimized MERS-S1 subunit vaccines fused with a foldon trimerization domain to mimic the native viral structure. They engineered immune stimulants (RS09 or flagellin, as TLR4 or TLR5 agonists) into this trimeric design and tested the pre-clinical immunogenicity of MERS-CoV vaccines in mice, distributed subcutaneously by needle injection or intracutaneously by dissolving microneedle arrays by assessing virus specific IgG antibodies in the serum of vaccinated mice by ELISA and using virus neutralization assays.

Microneedle array mediated immunization has several mechanistic differences from traditional intramuscular needle injections, which could clarify the variations in the magnitude and kinetics of the ensuing responses. Due to the urgent need for COVID-19 vaccines, they used this approach to quickly advance MNA SARS-CoV-2 subunit vaccines and tested their pre-clinical immunogenicity in-vivo by manipulating the previous research on MNA MERS-CoV vaccines.

Even though it is still premature to predict whether humans immunized with these vaccine candidates will have similar responses and be protected from SARS-CoV-2 infections, their previous research show that development, production, and initial animal testing of clinically translatable MNA vaccine candidates against SARS-CoV-2. Incidentally it will be vital to determine whether antibodies from MNA-SARS-CoV-2 immunized animals will neutralize virus infectivity.

Finally, we note that the immunogenicity differences between MNA coronavirus vaccines and coronavirus vaccines delivered by traditional needle injection that we observe will need to be evaluated in clinical trials to establish the clinical advantages of MNA delivery.

SOURCE

E. Kim et al., Microneedle array delivered recombinant coronavirus vaccines: Immunogenicity and rapid translational development, EBioMedicine (2020).

Fehr, Anthony R, and Stanley Perlman. Coronaviruses: an overview of their replication and pathogenesis. Methods in molecular biology, vol. 1282 (2015): 1-23.

Susan R. Weiss, Sonia Navas-Martin. Coronavirus Pathogenesis and the Emerging Pathogen Severe Acute Respiratory Syndrome Coronavirus. Microbiology and Molecular Biology Reviews Dec 2005, 69 (4) 635-664.

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