COVID-19 Vaccines Currently under Preclinical and Clinical Studies, and Associated Antiviral Immune Response

Immunogenicity of different nanoparticle adjuvants containing recombinant RBD coronavirus antigen in animal model

Ongoing mutations of SARS-CoV-2 present challenges for vaccine development, promising renewed global efforts to create more effective vaccines against coronavirus disease (COVID-19). One approach is to target highly immunogenic viral proteins, such as the spike receptor binding domain (RBD), which can stimulate the production of potent neutralizing antibodies. This study aimed to design and test a subunit vaccine candidate based on the RBD. Bioinformatics analysis identified antigenic regions of the RBD for recombinant protein design. In silico analysis identified the RBD region as a feasible target for designing a recombinant vaccine. Bioinformatics tools predicted the stability and antigenicity of epitopes, and a 3D model of the RBD-angiotensin-converting enzyme 2 complex was constructed using molecular docking and codon optimization. The resulting construct was cloned into the pET-28a (+) vector and successfully expressed in Escherichia coli BL21DE3. As evidenced by sodium dodecyl-polyacrylamide gel electrophoresis and Western blotting analyses, the affinity purification of RBD antigens produced high-quality products. Mice were immunized with the RBD antigen alone or combined with aluminum hydroxide (AlOH), calcium phosphate (CaP), or zinc oxide (ZnO) nanoparticles (NPs) as adjuvants. Enzyme-linked immunosorbent assay assays were used to evaluate immune responses in mice. In-silico analysis confirmed the stability and antigenicity of the designed protein structure. RBD with CaP NPs generated the highest immunoglobulin G titer compared to AlOH and ZnO after three doses, indicating its effectiveness as a vaccine platform. In conclusion, the recombinant RBD antigen administered with CaP adjuvant NPs induces potent humoral immunity in mice, supporting further vaccine development. These results contribute to ongoing efforts to develop more effective COVID-19 vaccines.

SARS-CoV-2 genetic variation and bacterial communities of naso-oropharyngeal samples in middle-aged and elderly COVID-19 patients in West Java, Indonesia

Objective

The number of COVID-19 cases in Indonesia reflects the disease severity and rapid dissemination. In response to the mounting threat, SARS-CoV-2 genomic surveillance and the investigation of naso-oropharyngeal bacterial communities in West Java were conducted, as dysbiosis of the upper respiratory tract microbiota might adversely affect the clinical condition of patients.

Methods

We utilized the Oxford Nanopore sequencing platform to analyze genetic variation of 43 samples of SARS-CoV-2 and 11 selected samples for 16S rRNA gene sequencing, using samples collected from May to August 2021.

Results

The prevalence of AY.23 (>82%) predominated among five virus lineages in the populations (AY.23, AY.24, AY.26, AY.42, B.1.1.7). The region in the SARS-CoV-2 genome found to have the highest number of mutations was the spike (S) protein (>20%). There was no association between SARS-CoV-2 lineages, mutation frequency, patient profile, and COVID-19 rapid spread-categorized cases. There was no association of bacterial relative abundance, alpha-beta diversity, and linear discriminant analysis effect size analysis with patient profile and rapid spread cases. MetagenomeSeq analysis showed eight differential abundance species in individual patient profiles, including Pseudomonas aeruginosa and Haemophilus parainfluenzae.

Conclusions

The data demonstrated relevant AY.23 dominance (the Delta variant) in West Java during that period supporting the importance of surveillance program in monitoring disease progression. The inconsistent results of the bacterial communities suggest that a complex multifactor process may contribute to the progression of bacterial-induced disease in each patient.

Pre-Clinical Safety and Immunogenicity Study of a Coronavirus Protein-Based Subunit Vaccine for COVID-19

Creating an effective and safe vaccine is critical to fighting the coronavirus infection successfully. Several types of COVID-19 vaccines exist, including inactivated, live attenuated, recombinant, synthetic peptide, virus-like particle-based, DNA and mRNA-based, and sub-unit vaccines containing purified immunogenic viral proteins. However, the scale and speed at which COVID-19 is spreading demonstrate a global public demand for an effective prophylaxis that must be supplied more. The developed products promise a bright future for SARS-CoV-2 prevention; however, evidence of safety and immunogenicity is mandatory before any vaccine can be produced. In this paper, we report on the results of our work examining the safety, toxicity, immunizing dose choice, and immunogenicity of QazCoVac-P, a Kazakhstan-made sub-unit vaccine for COVID-19. First, we looked into the product's safety profile by assessing its pyrogenicity in vaccinated rabbit models and using the LAL (limulus amebocyte lysate) test. We examined the vaccine's acute and sub-chronic toxicity on BALB/c mice and rats. The vaccine did not cause clinically significant toxicity-related changes or symptoms in our toxicity experiments. Finally, we performed a double immunization of mice, ferrets, Syrian hamsters, and rhesus macaques (Macaca mulatta). We used ELISA to measure antibody titers with the maximum mean geometric titer of antibodies in the animals' blood sera totaling approximately 8 log2. The results of this and other studies warrant recommending the QazCoVac-P vaccine for clinical trials.

Nano-based techniques: A revolutionary approach to prevent covid-19 and enhancing human awareness

In every century of history, there are many new diseases emerged, which are not even cured by many developed countries. Today, despite of scientific development, new deadly pandemic diseases are caused by microorganisms. Hygiene is considered to be one of the best methods of avoiding such communicable diseases, especially viral diseases. Illness caused by SARS-CoV-2 was termed COVID-19 by the WHO, the acronym derived from "coronavirus disease 2019. The globe is living in the worst epidemic era, with the highest infection and mortality rate owing to COVID-19 reaching 6.89% (data up to March 2023). In recent years, nano biotechnology has become a promising and visible field of nanotechnology. Interestingly, nanotechnology is being used to cure many ailments and it has revolutionized many aspects of our lives. Several COVID-19 diagnostic approaches based on nanomaterial have been developed. The various metal NPs, it is highly anticipated that could be viable and economical alternatives for treating drug resistant in many deadly pandemic diseases in near future. This review focuses on an overview of nanotechnology's increasing involvement in the diagnosis, prevention, and therapy of COVID-19, also this review provides readers with an awareness and knowledge of importance of hygiene.

Recent Advances in Quantum Dot-Based Lateral Flow Immunoassays for the Rapid, Point-of-Care Diagnosis of COVID-19

The COVID-19 pandemic has spurred demand for efficient and rapid diagnostic tools that can be deployed at point of care to quickly identify infected individuals. Existing detection methods are time consuming and they lack sensitivity. Point-of-care testing (POCT) has emerged as a promising alternative due to its user-friendliness, rapidity, and high specificity and sensitivity. Such tests can be conveniently conducted at the patient's bedside. Immunodiagnostic methods that offer the rapid identification of positive cases are urgently required. Quantum dots (QDs), known for their multimodal properties, have shown potential in terms of combating or inhibiting the COVID-19 virus. When coupled with specific antibodies, QDs enable the highly sensitive detection of viral antigens in patient samples. Conventional lateral flow immunoassays (LFAs) have been widely used for diagnostic testing due to their simplicity, low cost, and portability. However, they often lack the sensitivity required to accurately detect low viral loads. Quantum dot (QD)-based lateral flow immunoassays have emerged as a promising alternative, offering significant advancements in sensitivity and specificity. Moreover, the lateral flow immunoassay (LFIA) method, which fulfils POCT standards, has gained popularity in diagnosing COVID-19. This review focuses on recent advancements in QD-based LFIA for rapid POCT COVID-19 diagnosis. Strategies to enhance sensitivity using QDs are explored, and the underlying principles of LFIA are elucidated. The benefits of using the QD-based LFIA as a POCT method are highlighted, and its published performance in COVID-19 diagnostics is examined. Overall, the integration of quantum dots with LFIA holds immense promise in terms of revolutionizing COVID-19 detection, treatment, and prevention, offering a convenient and effective approach to combat the pandemic.

Real-world effectiveness of mRNA COVID-19 vaccines in the elderly during the Delta and Omicron variants: Systematic review

BACKGROUND

As of 31 December 2022, there were over 6.6 million coronavirus disease 2019 (COVID-19) deaths and over 651 million cases across 200 countries worldwide. Despite the increase in vaccinations and booster shots, COVID-19 cases and deaths continue to remain high. While the effectiveness of these vaccines has already been established by different manufacturers, the fact remains that these vaccines were created quickly for global emergency use, tested under controlled clinical conditions from voluntary subjects and age groups whose general characteristics may differ from the actual general population.

AIM

To conduct a systematic review to determine the real-world effectiveness of mRNA COVID-19 vaccines in the elderly during the predominance of Delta and Omicron variants in preventing COVID-19 related infection, hospital, intensive care unit (ICU) admission and intubation, and death.

METHODS

A combination of Medical Subject Headings and non-Medical Subject Headings was carried out to identify all relevant research articles that meets the inclusion and exclusion criteria from PubMed, Cochrane, CINAHL, Scopus, ProQuest, Embase, Web of Science, and Google Scholar databases, as well as qualified research studies from pre-print servers using medRxiv and Research Square, published from January 1, 2021 - December 31, 2022.

RESULTS

As per the inclusion and exclusion criteria, the effectiveness of Pfizer-BioNTech and Moderna vaccines were evaluated from an estimated total study population of 26,535,692 using infection, hospital, ICU admission and intubation, and death as outcome measures from studies published between 2021 and 2022, conducted in New York, Finland, Canada, Costa Rica, Qatar, Greece, and Brazil. The risk of bias was evaluated using risk of bias in nonrandomized studies of interventions (ROBINS-I) tool for cohort, case-control, and cross-sectional studies. While clinical trial data on Pfizer-BioNTech and Moderna vaccines demonstrated 94% vaccine effectiveness in the elderly, the results in this study showed that vaccine effectiveness in real-world settings is marginally lower against infection (40%-89%), hospitalization (92%), ICU admission and intubation (98%-85%), and death (77%-87%) with an indication of diminished effectiveness of vaccine over time. Furthermore, 2 doses of mRNA vaccines are inadequate and only provides interim protection.

CONCLUSION

Because of the natural diminishing effectiveness of the vaccine, the need for booster dose to restore its efficacy is vital. From a research perspective, the use of highly heterogeneous outcome measures inhibits the comparison, contrast, and integration of the results which makes data pooling across different studies problematic. While pharmaceutical intervention like vaccination is important to fight an epidemic, utilizing common outcome measurements or carrying out studies with minimal heterogeneity in outcome measurements, is equally crucial to better understand and respond to an international health crisis.

Lung development and regeneration: newly defined cell types and progenitor status

The lung is the most critical organ of the respiratory system supporting gas exchange. Constant interaction with the external environment makes the lung vulnerable to injury. Thus, a deeper understanding of cellular and molecular processes underlying lung development programs and evaluation of progenitor status within the lung is an essential part of lung regenerative medicine. In this review, we aim to discuss the current understanding of lung development process and regenerative capability. We highlight the advances brought by multi-omics approaches, single-cell transcriptome, in particular, that can help us further dissect the cellular player and molecular signaling underlying those processes.

Advanced Vaccine Design Strategies against SARS-CoV-2 and Emerging Variants

Vaccination is the most cost-effective means in the fight against infectious diseases. Various kinds of vaccines have been developed since the outbreak of COVID-19, some of which have been approved for clinical application. Though vaccines available achieved partial success in protecting vaccinated subjects from infection or hospitalization, numerous efforts are still needed to end the global pandemic, especially in the case of emerging new variants. Safe and efficient vaccines are the key elements to stop the pandemic from attacking the world now; novel and evolving vaccine technologies are urged in the course of fighting (re)-emerging infectious diseases. Advances in biotechnology offered the progress of vaccinology in the past few years, and lots of innovative approaches have been applied to the vaccine design during the ongoing pandemic. In this review, we summarize the state-of-the-art vaccine strategies involved in controlling the transmission of SARS-CoV-2 and its variants. In addition, challenges and future directions for rational vaccine design are discussed.

Tag-Free SARS-CoV-2 Receptor Binding Domain (RBD), but Not C-Terminal Tagged SARS-CoV-2 RBD, Induces a Rapid and Potent Neutralizing Antibody Response

Recombinant proteins are essential in the development of subunit vaccines. In the design of many recombinant proteins, polyhistidine residues are added to the N- or C-termini of target sequences to facilitate purification. However, whether the addition of tag residues influences the immunogenicity of proteins remains unknown. In this study, the tag-free SARS-CoV-2 RBD and His-tag SARS-CoV-2 RBD proteins were investigated to determine whether there were any differences in their receptor binding affinity and immunogenicity. The results showed that the tag-free RBD protein had a higher affinity for binding with hACE2 receptors than His-tag RBD proteins (EC₅₀: 1.78 µM vs. 7.51 µM). On day 21 after primary immunization with the proteins, the serum ELISA titers of immunized mice were measured and found to be 1:1418 for those immunized with tag-free RBD and only 1:2.4 for His-tag RBD. Two weeks after the booster dose, tag-free-RBD-immunized mice demonstrated a significantly higher neutralizing titer of 1:369 compared with 1:7.9 for His-tag-RBD-immunized mice. Furthermore, neutralizing antibodies induced by tag-free RBD persisted for up to 5 months and demonstrated greater cross-neutralization of the SARS-CoV-2 Delta variant. Evidence from Western blotting showed that the serum of His-tag-RBD-immunized mice recognized irrelevant His-tag proteins. Collectively, we conclude that the addition of a polyhistidine tag on a recombinant protein, when used as a COVID-19 vaccine antigen, may significantly impair protein immunogenicity against SARS-CoV-2. Antibody responses induced were clearly more rapid and robust for the tag-free SARS-CoV-2 RBD than the His-tag SARS-CoV-2 RBD. These findings provide important information for the design of antigens used in the development of COVID-19 subunit vaccines.

Saliva is suitable for SARS-CoV-2 antibodies detection after vaccination: A rapid systematic review

Since the introduction of efficient vaccines anti-SARS-CoV-2, antibody quantification becomes increasingly useful for immunological monitoring and COVID-19 control. In several situations, saliva samples may be an alternative to the serological test. Thus, this rapid systematic review aimed to evaluate if saliva is suitable for SARS-CoV-2 detection after vaccination. For this purpose, search strategies were applied at EMBASE, PubMed, and Web of Science. Studies were selected by two reviewers in a two-phase process. After selection, 15 studies were eligible and included in data synthesis. In total, salivary samples of approximately 1,080 vaccinated and/or convalescent individuals were analyzed. The applied vaccines were mostly mRNA-based (BioNTech 162b2 mRNA/Pfizer and Spikevax mRNA-1273/Moderna), but recombinant viral-vectored vaccines (Ad26. COV2. S Janssen - Johnson & Johnson and Vaxzevria/Oxford AstraZeneca) were also included. Different techniques were applied for saliva evaluation, such as ELISA assay, Multiplex immunoassay, flow cytometry, neutralizing and electrochemical assays. Although antibody titers are lower in saliva than in serum, the results showed that saliva is suitable for antibody detection. The mean of reported correlations for titers in saliva and serum/plasma were moderate for IgG (0.55, 95% CI 0.38-9.73), and weak for IgA (0.28, 95% CI 0.12-0.44). Additionally, six out of nine studies reported numerical titers for immunoglobulins detection, from which the level in saliva reached their reference value in four (66%). IgG but not IgA are frequently presented in saliva from vaccinated anti-COVID-19. Four studies reported lower IgA salivary titers in vaccinated compared to previously infected individuals, otherwise, two reported higher titers of IgA in vaccinated. Concerning IgG, two studies reported high antibody titers in the saliva of vaccinated individuals compared to those previously infected and one presented similar results for vaccinated and infected. The detection of antibodies anti-SARS-CoV-2 in the saliva is available, which suggests this type of sample is a suitable alternative for monitoring the population. Thus, the results also pointed out the possible lack of mucosal immunity induction after anti-SARS-CoV-2 vaccination. It highlights the importance of new vaccination strategies also focused on mucosal alternatives directly on primary routes of SARS-CoV-2 entrance.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022336968, identifier CRD42022336968.

Immunogenicity profiling and distinct immune response in liver transplant recipients vaccinated with SARS-CoV-2 inactivated vaccines

SARS-CoV-2 vaccination has been recommended for liver transplant (LT) recipients. However, our understanding of inactivated vaccine stimulation of the immune system in regulating humoral and cellular immunity among LT recipients is inadequate. Forty-six LT recipients who received two-dose inactivated vaccines according to the national vaccination schedule were enrolled. The clinical characteristics, antibody responses, single-cell peripheral immune profiling, and plasma cytokine/chemokine/growth factor levels were recorded. Sixteen (34.78%) LT recipients with positive neutralizing antibody (nAb) were present in the Type 1 group. Fourteen and 16 LT recipients with undetected nAb were present in the Type 2 and Type 3 groups, respectively. Time from transplant and lymphocyte count were different among the three groups. The levels of anti-RBD and anti-S1S2 decreased with decreasing neutralizing inhibition rates. Compared to the Type 2 and Type 3 groups, the Type 1 group had an enhanced innate immune response. The proportions of B, DNT, and CD3+CD19+ cells were increased in the Type 1 group, whereas monocytes and CD4+ T cells were decreased. High CD19, high CD8+CD45RA+ cells, and low effector memory CD4+/naïve CD4+ cells of the T-cell populations were present in the Type 1 group. The Type 1 group had higher concentrations of plasma CXCL10, MIP-1 beta, and TNF-alpha. No severe adverse events were reported in all LT recipients. We identified the immune responses induced by inactivated vaccines among LT recipients and provided insights into the identification of immunotypes associated with the responders.

A Review of Different Vaccines and Strategies to Combat COVID-19

In December 2019, an unknown viral infection emerged and quickly spread worldwide, resulting in a global pandemic. This novel virus caused severe pneumonia and acute respiratory distress syndrome caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). It has caused 6.25 millions of deaths worldwide and remains a major concern for health, society, and the economy. As vaccination is one of the most efficient ways to combat this pandemic, different vaccines were developed in a short period. This review article discusses how coronavirus affected the top nations of the world and the vaccines being used for the prevention. Amongst the vaccines, some vaccines have already been approved, and some have been involved in clinical studies. The article also provides insight into different COVID-19 vaccine platforms, their preparation, working, efficacy, and side effects.

Application of microneedle patches for drug delivery; doorstep to novel therapies

In the past decade, microneedle-based drug delivery systems showed promising approaches to become suitable and alternative for hypodermic injections and can control agent delivery without side effects compared to conventional approaches. Despite these advantages, the procedure of microfabrication is facing some difficulties. For instance, drug loading method, stability of drugs, and retention time are subjects of debate. Besides, the application of novel refining fabrication methods, types of materials, and instruments are other issues that need further attention. Herein, we tried to summarize recent achievements in controllable drug delivery systems (microneedle patches) in vitro and in vivo settings. In addition, we discussed the influence of delivered drugs on the cellular mechanism and immunization molecular signaling pathways through the intradermal delivery route. Understanding the putative efficiency of microneedle patches in human medicine can help us develop and design sophisticated therapeutic modalities.

In-silico screening of naturally derived phytochemicals against SARS-CoV Main protease

Coronavirus disease 2019 (COVID-19) is a rapidly growing pandemic that requires urgent therapeutic intervention. Finding potential anti COVID-19 drugs aside from approved vaccines is progressively going on. The chemically diverse natural products represent valuable sources for drug leads. In this study, we aimed to find out safe and effective COVID-19 protease inhibitors from a library of natural products which share the main nucleus/skeleton of FDA-approved drugs that were employed in COVID-19 treatment guidelines or repurposed by previous studies. Our library was subjected to virtual screening against SARS-CoV Main protease (Mpro) using Molecular Operating Environment (MOE) software. Twenty-two out of those natural candidates showed higher binding scores compared to their analogues. We repurpose these natural products including alkaloids, glucosinolates, and phenolics as potential platforms for the development of anti-SARS-CoV-2 therapeutics. This study paves the way towards discovering a lead used in the treatment of COVID-19 from natural sources and introduces phytomedicines with dual therapeutic effects against COVID-19 besides their original pharmacological effects. We recommend further in vitro evaluation of their anti-COVID-19 activity and future clinical studies.

Current hurdles to the translation of nanomedicines from bench to the clinic

The field of nanomedicine has significantly influenced research areas such as drug delivery, diagnostics, theranostics, and regenerative medicine; however, the further development of this field will face significant challenges at the regulatory level if related guidance remains unclear and unconsolidated. This review describes those features and pathways crucial to the clinical translation of nanomedicine and highlights considerations for early-stage product development. These include identifying those critical quality attributes of the drug product essential for activity and safety, appropriate analytical methods (physical, chemical, biological) for characterization, important process parameters, and adequate pre-clinical models. Additional concerns include the evaluation of batch-to-batch consistency and considerations regarding scaling up that will ensure a successful reproducible manufacturing process. Furthermore, we advise close collaboration with regulatory agencies from the early stages of development to assure an aligned position to accelerate the development of future nanomedicines.

Novel Strategies of Immunization against COVID-19

COVID-19 manifested itself as a global pandemic in 2019 but even in 2021, it is still not successfully contained. This virus has claimed millions of lives worldwide and rendered many more jobless. Apart from causing mild to severe pneumonia, the virus has also caused a loss of livelihood for thousands globally, along with widespread trauma and depression. Since the transmission rate of the virus is so high, temporary prophylaxis relied on sanitization, wearing masks and physical distancing. However, a long-term solution for stopping viral spread is vaccination. Apart from being the fastest way to induce immunity against the virus, vaccination is also the cheapest and most practical way. However, a vaccine can only be commercially available after it has passed through various clinical trial phases. So far, more than two hundred potential vaccine candidates underwent different phases of the clinical trial, and some of the front-runners have shown more than 90% efficacy. This review has compiled all such vaccine candidates, their types, their modes of action, and the associated pros and cons. The current advances in clinical trials of vaccines have also been discussed, such as plant-based and cocktail vaccines that have recently emerged. Nowadays, novel strains like Delta plus are also emerging and posing a threat. Thus, it is mandatory to get vaccinated and choose a vaccine that provides long-term protection against multiple strains.

A brief review on DNA vaccines in the era of COVID-19

This article provides a brief overview of DNA vaccines. First, the basic DNA vaccine design strategies are described, then specific issues related to the industrial production of DNA vaccines are discussed, including the production and purification of DNA products such as plasmid DNA, minicircle DNA, minimalistic, immunologically defined gene expression (MIDGE) and Doggybone™. The use of adjuvants to enhance the immunogenicity of DNA vaccines is then discussed. In addition, different delivery routes and several physical and chemical methods to increase the efficacy of DNA delivery into cells are explained. Recent preclinical and clinical trials of DNA vaccines for COVID-19 are then summarized. Lastly, the advantages and obstacles of DNA vaccines are discussed.

Neutralizing antibody responses following natural SARS-CoV-2 infection: Dynamics and correlation with commercial serologic tests

The prediction of SARS-CoV-2 immunity by commercially available serologic tests will be crucial to assess the efficacy of vaccination. We used plaque reduction neutralization testing as the reference standard to evaluate the diagnostic performance of six commercial serologic tests for monitoring SARS-CoV-2 neutralizing antibodies. Euroimmun ELISA anti-spike 1 IgG, Euroimmun anti-spike 1 IgG QuantiVac ELISA, Elecsys Anti-nucleocapsid protein total antibodies, Elecsys Anti-receptor-binding domain total antibodies, VIDAS anti-spike subdomain IgG, and Microblot-Array COVID-19 IgG assay were performed on 228 sera from 89 healthcare workers who participated in a six-month seroprevalence survey. Although all immunoassays demonstrated similar performances, VIDAS SARS-CoV-2 IgG and Euroimmun QuantiVac IgG (area under the curve 0.96 and 0.95 respectively) showed the better ability to detect Nabs. Except for the Elecsys Anti-SARS-CoV-2 and the Elecsys Anti-SARS-CoV-2 S assays, the commercial serologic tests evaluated here showed a significant decrease of antibody titers in the 6-month follow-up samples. Depending on the immunoassay, 21% to 33% of the participants became seronegative, and 16.9% had a loss of neutralizing antibodies. Microblot-Array assay results showed cross-reactivity with HCoVNL63 in only one sample, and this sample showed SARS-CoV-2 neutralizing capacity. In conclusion, our results support the use of VIDAS SARS-CoV-2 IgG, Euroimmun Anti-SARS-CoV-2 ELISA IgG, Euroimmun Anti-SARS-CoV-2 QuantiVac ELISA IgG and Microblot-Array COVID-19 IgG assays to monitor neutralizing antibody response following natural SARS-CoV-2 infection. These immunoassays could facilitate the prediction of post-vaccine protection in the long term and the allocation of booster doses.

Qualification of ELISA and neutralization methodologies to measure SARS-CoV-2 humoral immunity using human clinical samples

In response to the SARS-CoV-2 pandemic many vaccines have been developed and evaluated in human clinical trials. The humoral immune response magnitude, composition and efficacy of neutralizing SARS-CoV-2 are essential endpoints for these trials. Robust assays that are reproducibly precise, linear, and specific for SARS-CoV-2 antigens would be beneficial for the vaccine pipeline. In this work we describe the methodologies and clinical qualification of three SARS-CoV-2 endpoint assays. We developed and qualified Endpoint titer ELISAs for total IgG, IgG1, IgG3, IgG4, IgM and IgA to evaluate the magnitude of specific responses to the trimeric spike (S) antigen and total IgG specific to the spike receptor binding domain (RBD) of SARS-CoV-2. We also qualified a pseudovirus neutralization assay which evaluates functional antibody titers capable of inhibiting the entry and replication of a lentivirus containing the Spike antigen of SARS-CoV-2. To complete the suite of assays we qualified a plaque reduction neutralization test (PRNT) methodology using the 2019-nCoV/USA-WA1/2020 isolate of SARS-CoV-2 to assess neutralizing titers of antibodies in plasma from normal healthy donors and convalescent COVID-19 individuals.

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Precision, Linearity, and Specificity are essential for Clinical Assay Qualification.

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Vaccine or Infection-induced humoral response magnitude can be evaluated by high-throughput ELISAs.

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Neutralization of SARS-CoV-2 is the gold-standard for in vitro vaccine efficacy evaluations.

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ELISA, pseudovirus neutralization and PRNT assays are Clinically Qualified for SARS-CoV-2 vaccine trials.

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Positive WHO control sample of 250 ABU equals 4.7 EPT for total IgG against SARS-CoV-2 trimeric spike antigen in ELISAs.

Clinical approval of nanotechnology-based SARS-CoV-2 mRNA vaccines: impact on translational nanomedicine

One year after the first human case of SARS-CoV-2, two nanomedicine-based mRNA vaccines have been fast-tracked, developed, and have received emergency use authorization throughout the globe with more vaccine approvals on the heels of these first two. Several SARS-CoV-2 vaccine compositions use nanotechnology-enabled formulations. A silver lining of the COVID-19 pandemic is that the fast-tracked vaccine development for SARS-CoV-2 has advanced the clinical translation pathway for nanomedicine drug delivery systems. The laboratory science of lipid-based nanoparticles was ready and rose to the clinical challenge of rapid vaccine development. The successful development and fast tracking of SARS-CoV-2 nanomedicine vaccines has exciting implications for the future of nanotechnology-enabled drug and gene delivery; it demonstrates that nanomedicine is necessary and critical to the successful delivery of advanced molecular therapeutics such as nucleic acids, it is establishing the precedent of safety and the population effect of phase four clinical trials, and it is laying the foundation for the clinical translation of more complex, non-lipid nanomedicines. The development, fast-tracking, and approval of SARS-CoV-2 nanotechnology-based vaccines has transformed the seemingly daunting challenges for clinically translating nanomedicines into measurable hurdles that can be overcome. Due to the tremendous scientific achievements that have occurred in response to the COVID-19 pandemic, years, perhaps even decades, have been streamlined for certain translational nanomedicines.

Coronavirus Disease (COVID)-19 and Diabetic Kidney Disease

The present review describes COVID-19 severity in diabetes and diabetic kidney disease. We discuss the crucial effect of COVID-19-associated cytokine storm and linked injuries and associated severe mesenchymal activation in tubular epithelial cells, endothelial cells, and macrophages that influence neighboring cell homeostasis, resulting in severe proteinuria and organ fibrosis in diabetes. Altered microRNA expression disrupts cellular homeostasis and the renin-angiotensin-system, targets reno-protective signaling proteins, such as angiotensin-converting enzyme 2 (ACE2) and MAS1 receptor (MAS), and facilitates viral entry and replication in kidney cells. COVID-19-associated endotheliopathy that interacts with other cell types, such as neutrophils, platelets, and macrophages, is one factor that accelerates prethrombotic reactions and thrombus formation, resulting in organ failures in diabetes. Apart from targeting vital signaling through ACE2 and MAS, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are also associated with higher profibrotic dipeptidyl transferase-4 (DPP-4)-mediated mechanisms and suppression of AMP-activated protein kinase (AMPK) activation in kidney cells. Lowered DPP-4 levels and restoration of AMPK levels are organ-protective, suggesting a pathogenic role of DPP-4 and a protective role of AMPK in diabetic COVID-19 patients. In addition to standard care provided to COVID-19 patients, we urgently need novel drug therapies that support the stability and function of both organs and cell types in diabetes.

Current vaccine technology with an emphasis on recombinant measles virus as a new perspective for vaccination against SARS-CoV-2

The novel coronavirus disease 2019 (COVID-19) that emerged in China has spread to more than 212 countries to date. COVID-19 can cause serious acute respiratory syndrome (SARS). Therefore, research advances on the associated SARS-coronavirus-2 (CoV-2) may enable the scientific community to establish effective vaccines to prevent SARS-CoV-2 infections by increasing understanding of viral pathogenesis. Measles virus (MV) expressing SARS-CoV-2 spike protein (S) represents a promising class of biotherapeutic agents to combat this virus. The potential of such recombinant viruses has been well recognized for the treatment of many diseases. We summarize and review herein a potential therapeutic intervention strategy against COVID-19 infection based on MVSchw2-SARS-S and MVSchw2-SARS-Ssol with the aim of assessing the suitability of recombinant MV as a potential new candidate SARS vaccine. Such analysis of COVID-19 pathogenesis could also help establish appropriate therapeutic targets for the production of specific antiviral agents against this newly emerged pathogen.

Qualification of ELISA and neutralization methodologies to measure SARS-CoV-2 humoral immunity using human clinical samples

In response to the SARS-CoV-2 pandemic many vaccines have been developed and evaluated in human clinical trials. The humoral immune response magnitude, composition and efficacy of neutralizing SARS-CoV-2 are essential endpoints for these trials. Robust assays that are reproducibly precise, linear, and specific for SARS-CoV-2 antigens would be beneficial for the vaccine pipeline. In this work we describe the methodologies and clinical qualification of three SARS-CoV-2 endpoint assays. We developed and qualified Endpoint titer ELISAs for total IgG, IgG1, IgG3, IgG4, IgM and IgA to evaluate the magnitude of specific responses to the trimeric spike (S) antigen and total IgG specific to the spike receptor binding domain (RBD) of SARS-CoV-2. We also qualified a pseudovirus neutralization assay which evaluates functional antibody titers capable of inhibiting the entry and replication of a lentivirus containing the Spike antigen of SARS-CoV-2. To complete the suite of assays we qualified a plaque reduction neutralization test (PRNT) methodology using the 2019-nCoV/USA-WA1/2020 isolate of SARS-CoV-2 to assess neutralizing titers of antibodies in plasma from normal healthy donors and convalescent COVID-19 individuals.

A Summary of the SARS-CoV-2 Vaccines and Technologies Available or under Development

Since the beginning of 2020, the world has been in a race to develop vaccines that can control the COVID-19 pandemic. More than 250 projects have been initiated for this purpose, but only 14 of them have been authorized for use, despite being in phase 3 clinical trials. More than 40 other vaccines are also in phase 1/2 clinical trials and show promising outcomes. Regarding the appropriate choice of vaccines for each country or region, we reviewed the currently used vaccines in light of the different influencing parameters. These factors include the mode of action, dosage protocol, age group of the vaccinee, side effects, storage conditions, mounted immune response, and cost. Technically, there are seven types of vaccines developed against SARS-CoV-2: messenger RNA (mRNA), nonreplicating and replicating vectors, inactivated viruses, protein subunits, viral-like particles, DNA vaccines, and live attenuated vaccines. The mRNA type is being used for the first time in humans. Unfortunately, mutated variants of SARS-CoV-2 have started to appear worldwide, and researchers are investigating the effects of the currently used vaccines on them. There are many concerns regarding the long-term protection afforded by these vaccines and their side effects, and whether they require future modifications to be effective against the mutated variants. The development of new vaccines using more advanced technology is paramount for overcoming the difficulties in controlling the COVID-19 pandemic across the world.

COVID-19 Vaccine Acceptability and Adherence to Preventive Measures in Somalia: Results of an Online Survey

Most countries are currently gravitating towards vaccination as mainstay strategy to quell COVID-19 transmission. Between December 2020 and January 2021, we conducted a follow-up online survey in Somalia to monitor adherence to COVID-19 preventive measures, and COVID-19 vaccine acceptability and reasons for vaccine hesitancy. Adherence was measured via a composite adherence score based on four measures (physical distancing, face mask use, hand hygiene, and mouth covering when coughing/sneezing). We analyzed 4543 responses (mean age: 23.5 ± 6.4 years, 62.4% males). The mean adherence score during this survey was lower than the score during a similar survey in April 2020. A total of 76.8% of respondents were willing to receive the COVID-19 vaccine. Flu-like symptoms were more frequently reported in the current survey compared to previous surveys. Multiple logistic regression showed that participants who experienced flu-like symptoms, those in the healthcare sector, and those with higher adherence scores had higher odds for vaccine acceptability while being a female reduced the willingness to be vaccinated. In conclusion, our data suggest that the decreasing adherence to COVID-19 preventive measures may have caused increased flu-like symptoms over time. COVID-19 vaccine acceptance in Somalia is relatively high but could be improved by addressing factors that contribute to vaccine hesitancy.

An update review of globally reported SARS-CoV-2 vaccines in preclinical and clinical stages

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the rapidly spreading pandemic COVID-19 in the world. As an effective therapeutic strategy is not introduced yet and the rapid genetic variations in the virus, there is an emerging necessity to design, evaluate and apply effective new vaccines. An acceptable vaccine must elicit both humoral and cellular immune responses, must have the least side effects and the storage and transport systems should be available and affordable for all countries. These vaccines can be classified into different types: inactivated vaccines, live-attenuated virus vaccines, subunit vaccines, virus-like particles (VLPs), nucleic acid-based vaccines (DNA and RNA) and recombinant vector-based vaccines (replicating and non-replicating viral vector). According to the latest update of the WHO report on April 2nd, 2021, at least 85 vaccine candidates were being studied in clinical trial phases and 184 candidate vaccines were being evaluated in pre-clinical stages. In addition, studies have shown that other vaccines, including the Bacillus Calmette-Guérin (BCG) vaccine and the Plant-derived vaccine, may play a role in controlling pandemic COVID-19. Herein, we reviewed the different types of COVID-19 candidate vaccines that are currently being evaluated in preclinical and clinical trial phases along with advantages, disadvantages or adverse reactions, if any.

Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates

Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.

Spike S2 Subunit: The Dark Horse in the Race for Prophylactic and Therapeutic Interventions against SARS-CoV-2

In the midst of the unceasing COVID-19 pandemic, the identification of immunogenic epitopes in the SARS-CoV-2 spike (S) glycoprotein plays a vital role in the advancement and development of intervention strategies. S is expressed on the exterior of the SARS-CoV-2 virion and contains two subunits, namely the N-terminal S1 and C-terminal S2. It is the key element for mediating viral entry as well as a crucial antigenic determinant capable of stimulating protective immune response through elicitation of anti-SARS-CoV-2 antibodies and activation of CD4+ and CD8+ cells in COVID-19 patients. Given that S2 is highly conserved in comparison to the S1, here, we provide a review of the latest findings on the SARS-CoV-2 S2 subunit and further discuss its potential as an attractive and promising target for the development of prophylactic vaccines and therapeutic agents against COVID-19.

COVID-19 and Dentistry in 72 Questions: An Overview of the Literature

The outbreak of Coronavirus Disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has significantly affected the dental care sector. Dental professionals are at high risk of being infected, and therefore transmitting SARS-CoV-2, due to the nature of their profession, with close proximity to the patient's oropharyngeal and nasal regions and the use of aerosol-generating procedures. The aim of this article is to provide an update on different issues regarding SARS-CoV-2 and COVID-19 that may be relevant for dentists. Members of the French National College of Oral Biology Lecturers ("Collège National des EnseignantS en Biologie Orale"; CNESBO-COVID19 Task Force) answered seventy-two questions related to various topics, including epidemiology, virology, immunology, diagnosis and testing, SARS-CoV-2 transmission and oral cavity, COVID-19 clinical presentation, current treatment options, vaccine strategies, as well as infection prevention and control in dental practice. The questions were selected based on their relevance for dental practitioners. Authors independently extracted and gathered scientific data related to COVID-19, SARS-CoV-2 and the specific topics using scientific databases. With this review, the dental practitioners will have a general overview of the COVID-19 pandemic and its impact on their practice.

COVID-19 Vaccine Acceptance in the Democratic Republic of Congo: A Cross-Sectional Survey

We investigated the level of willingness for COVID-19 vaccination in the Democratic Republic of Congo (DRC). Data were collected between 24 August 2020 and 8 September 2020 through an online survey. A total of 4131 responses were included; mean age of respondents was 35 years (standard deviation: 11.5); 68.4% were females; 71% had elementary or secondary school education. One fourth (24.1%) were convinced that COVID-19 did not exist. Overall, 2310 (55.9%) indicated they were willing to be vaccinated. In a multivariable regression model, belonging to the middle and high-income category (OR = 1.85, CI: 1.46-2.35 and OR = 2.91, CI: 2.15-3.93, respectively), being tested for COVID-19 (OR = 4.71, CI: 3.62-6.12; p < 0.001), COVID-19 community vaccine acceptance (OR = 14.45, CI: 2.91-71.65; p = 0.001) and acknowledging the existence of COVID-19 (OR = 6.04, CI: 4.42-8.23; p < 0.001) were associated with an increased willingness to be vaccinated. Being a healthcare worker was associated with a decreased willingness for vaccination (OR = 0.46, CI: 0.36-0.58; p < 0.001). In conclusion, the current willingness for COVID-19 vaccination among citizens of the DRC is too low to dramatically decrease community transmission. Of great concern is the low intention of immunization among healthcare workers. A large sensitization campaign will be needed to increase COVID-19 vaccine acceptance.

A COVID-19 Vaccine: Big Strides Come with Big Challenges

As of 8 January 2021, there were 86,749,940 confirmed coronavirus disease 2019 (COVID-19) cases and 1,890,342 COVID-19-related deaths worldwide, as reported by the World Health Organization (WHO). In order to address the COVID-19 pandemic by limiting transmission, an intense global effort is underway to develop a vaccine against SARS-CoV-2. The development of a safe and effective vaccine usually requires several years of pre-clinical and clinical stages of evaluation and requires strict regulatory approvals before it can be manufactured in bulk and distributed. Since the global impact of COVID-19 is unprecedented in the modern era, the development and testing of a new vaccine are being expedited. Given the high-level of attrition during vaccine development, simultaneous testing of multiple candidates increases the probability of finding one that is effective. Over 200 vaccines are currently in development, with over 60 candidate vaccines being tested in clinical trials. These make use of various platforms and are at different stages of development. This review discusses the different phases of vaccine development and the various platforms in use for candidate COVID-19 vaccines, including their progress to date. The potential challenges once a vaccine becomes available are also addressed.

Vaccination Criteria Based on Factors Influencing COVID-19 Diffusion and Mortality

SARS-CoV-2 is highly contagious, rapidly turned into a pandemic, and is causing a relevant number of critical to severe life-threatening COVID-19 patients. However, robust statistical studies of a large cohort of patients, potentially useful to implement a vaccination campaign, are rare. We analyzed public data of about 19,000 patients for the period 28 February to 15 May 2020 by several mathematical methods. Precisely, we describe the COVID-19 evolution of a number of variables that include age, gender, patient’s care location, and comorbidities. It prompts consideration of special preventive and therapeutic measures for subjects more prone to developing life-threatening conditions while affording quantitative parameters for predicting the effects of an outburst of the pandemic on public health structures and facilities adopted in response. We propose a mathematical way to use these results as a powerful tool to face the pandemic and implement a mass vaccination campaign. This is done by means of priority criteria based on the influence of the considered variables on the probability of both death and infection.