An overview of vaccine development for COVID-19

The COVID-19 pandemic continues to endanger world health and the economy. The causative SARS-CoV-2 coronavirus has a unique replication system. The end point of the COVID-19 pandemic is either herd immunity or widespread availability of an effective vaccine. Multiple candidate vaccines – peptide, virus-like particle, viral vectors (replicating and nonreplicating), nucleic acids (DNA or RNA), live attenuated virus, recombinant designed proteins and inactivated virus – are presently under various stages of expansion, and a small number of vaccine candidates have progressed into clinical phases. At the time of writing, three major pharmaceutical companies, namely Pfizer and Moderna, have their vaccines under mass production and administered to the public. This review aims to investigate the most critical vaccines developed for COVID-19 to date.

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Strategies for Vaccination: Conventional Vaccine Approaches Versus New-Generation Strategies in Combination with Adjuvants

Pharmaceutics ◽

10.3390/pharmaceutics13020140 ◽

2021 ◽

Vol 13 (2) ◽

pp. 140

Author(s):

Abdellatif Bouazzaoui ◽

Ahmed A. H. Abdellatif ◽

Faisal A. Al-Allaf ◽

Neda M. Bogari ◽

Saied Al-Dehlawi ◽

...

Keyword(s):

Viral Vectors ◽

Protein Production ◽

Vaccine Development ◽

Effective Vaccine ◽

The Novel ◽

Research Teams ◽

Advantages And Disadvantages ◽

Rapid Spread ◽

New Generation ◽

Conventional Vaccine

The current COVID-19 pandemic, caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has raised significant economic, social, and psychological concerns. The rapid spread of the virus, coupled with the absence of vaccines and antiviral treatments for SARS-CoV-2, has galvanized a major global endeavor to develop effective vaccines. Within a matter of just a few months of the initial outbreak, research teams worldwide, adopting a range of different strategies, embarked on a quest to develop effective vaccine that could be effectively used to suppress this virulent pathogen. In this review, we describe conventional approaches to vaccine development, including strategies employing proteins, peptides, and attenuated or inactivated pathogens in combination with adjuvants (including genetic adjuvants). We also present details of the novel strategies that were adopted by different research groups to successfully transfer recombinantly expressed antigens while using viral vectors (adenoviral and retroviral) and non-viral delivery systems, and how recently developed methods have been applied in order to produce vaccines that are based on mRNA, self-amplifying RNA (saRNA), and trans-amplifying RNA (taRNA). Moreover, we discuss the methods that are being used to enhance mRNA stability and protein production, the advantages and disadvantages of different methods, and the challenges that are encountered during the development of effective vaccines.

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Intention to Be Vaccinated for COVID-19 among Italian Nurses during the Pandemic

Vaccines ◽

10.3390/vaccines9050500 ◽

2021 ◽

Vol 9 (5) ◽

pp. 500

Author(s):

Marco Trabucco Aurilio ◽

Francesco Saverio Mennini ◽

Simone Gazzillo ◽

Laura Massini ◽

Matteo Bolcato ◽

...

Keyword(s):

Vaccine Efficacy ◽

Online Survey ◽

Vaccine Development ◽

Vaccine Coverage ◽

World Health ◽

Vaccine Hesitancy ◽

Effective Vaccine ◽

Online Questionnaire ◽

Cross Sectional ◽

Female Sex

Background: While the COVID-19 pandemic has spread globally, health systems are overwhelmed by both direct and indirect mortality from other treatable conditions. COVID-19 vaccination was crucial to preventing and eliminating the disease, so vaccine development for COVID-19 was fast-tracked worldwide. Despite the fact that vaccination is commonly recognized as the most effective approach, according to the World Health Organization (WHO), vaccine hesitancy is a global health issue. Methods: We conducted a cross-sectional online survey of nurses in four different regions in Italy between 20 and 28 December 2020 to obtain data on the acceptance of the upcoming COVID-19 vaccination in order to plan specific interventions to increase the rate of vaccine coverage. Results: A total of 531 out of the 5000 nurses invited completed the online questionnaire. Most of the nurses enrolled in the study (73.4%) were female. Among the nurses, 91.5% intended to accept vaccination, whereas 2.3% were opposed and 6.2% were undecided. Female sex and confidence in vaccine efficacy represent the main predictors of vaccine intention among the study population using a logistic regression model, while other factors including vaccine safety concerns (side effects) were non-significant. Conclusions: Despite the availability of a safe and effective vaccine, intention to be vaccinated was suboptimal among nurses in our sample. We also found a significant number of people undecided as to whether to accept the vaccine. Contrary to expectations, concerns about the safety of the vaccine were not found to affect the acceptance rate; nurses’ perception of vaccine efficacy and female sex were the main influencing factors on attitudes toward vaccination in our sample. Since the success of the COVID-19 immunization plan depends on the uptake rate, these findings are of great interest for public health policies. Interventions aimed at increasing employee awareness of vaccination efficacy should be promoted among nurses in order to increase the number of vaccinated people.

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Recent Advances in Clinical Trials of HCV Vaccines

Journal of Applied Virology ◽

10.21092/jav.v3i1.48 ◽

2014 ◽

Vol 3 (1) ◽

pp. 10 ◽

Cited By ~ 2

Author(s):

Yongneng Luo ◽

Limin Jiang ◽

Zi'an Mao

Keyword(s):

Clinical Trials ◽

Viral Vectors ◽

Vaccine Development ◽

Viral Vector ◽

Core Protein ◽

Therapeutic Vaccine ◽

Hcv Infection ◽

Effective Vaccine ◽

Protein Subunit ◽

Preclinical Development

<p> Hepatitis C virus infects nearly 3% of the global population, and spreads to 3-4 million new people annually. HCV infection is a leading cause of liver cirrhosis, hepatocellular carcinoma, and end-stage liver diseases and causes liver-related death in more than 300,000 people each year. Unfortunately, there is currently no vaccine for HCV prevention (prophylactic vaccine) or treatment (therapeutic vaccine). Circulating HCV is genetically diverse, and therefore a broadly effective vaccine must target conserved T- and B-cell epitopes of the virus and induce strong cross-reactive CD4+/CD8+ T-cell and neutralizing antibody responses in preventing or clearing HCV infection. So far, a few of vaccine development approaches are successful and some of the HCV vaccine candidates have reached human clinical trials, including those modalities mainly based on recombinant proteins (envelope proteins and core protein subunit), synthetic peptides, DNA (plasmid) and viral vectors (virosome). Encouraging results were obtained for those HCV vaccine formulations consisting of prime-boost regimen involving a live recombinant viral vector vaccine alone or in combination with DNA or subunit vaccine. Among several other vaccine strategies under preclinical development, the most promising one is virus like particle based vaccine that will be moving into human studies soon.</p>

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Modeling the COVID-19 outbreaks and the effectiveness of the containment measures adopted across countries

10.1101/2020.04.02.20046375 ◽

2020 ◽

Cited By ~ 9

Author(s):

Edward De Brouwer ◽

Daniele Raimondi ◽

Yves Moreau

Keyword(s):

Herd Immunity ◽

Case Fatality ◽

Severe Pneumonia ◽

Optimal Level ◽

World Health ◽

Reproduction Ratio ◽

The Public ◽

Global Pandemic ◽

Containment Measures ◽

Health Organization

AbstractOn March 11, 2020, the World Health Organization declared the COVID-19 outbreak, originally started in China, a global pandemic. Since then, the outbreak has indeed spread across all continents, threatening the public health of numerous countries. Although the Case Fatality Rate (CFR) of COVID-19 is relatively low when optimal level of healthcare is granted to the patients, the high percentage of severe cases developing severe pneumonia and thus requiring respiratory support is worryingly high, and could lead to a rapid saturation of Intensive Care Units (ICUs). To overcome this risk, most countries enacted COVID-19 containment measures. In this study, we use a Bayesian SEIR epidemiological model to perform a parametric regression over the COVID-19 outbreaks data in China, Italy, Belgium, and Spain, and estimate the effect of the containment measures on the basic reproduction ratio R0.We find that the effect of these measures is detectable, but tends to be gradual, and that a progressive strengthening of these measures usually reduces the R0 below 1, granting a decay of the outbreak. We also discuss the biases and inconsistencies present in the publicly available data on COVID-19 cases, providing an estimate for the actual number of cases in Italy on March 12, 2020. Lastly, despite the data and model’s limitations, we argue that the idea of “flattening the curve” to reach herd immunity is likely to be unfeasible.

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Developmental Landscape of Potential Vaccine Candidates Based on Viral Vector for Prophylaxis of COVID-19

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.635337 ◽

2021 ◽

Vol 8 ◽

Author(s):

Rajashri Bezbaruah ◽

Pobitra Borah ◽

Bibhuti Bhushan Kakoti ◽

Nizar A. Al-Shar’I ◽

Balakumar Chandrasekaran ◽

...

Keyword(s):

Viral Vectors ◽

Ebola Virus ◽

Vaccine Development ◽

Viral Vector ◽

World Health ◽

Prolonged Incubation ◽

Vaccine Candidates ◽

Vector Vaccine ◽

Dna And Rna ◽

Viral Vector Vaccine

Severe acute respiratory syndrome coronavirus 2, SARS-CoV-2, arose at the end of 2019 as a zoonotic virus, which is the causative agent of the novel coronavirus outbreak COVID-19. Without any clear indications of abatement, the disease has become a major healthcare threat across the globe, owing to prolonged incubation period, high prevalence, and absence of existing drugs or vaccines. Development of COVID-19 vaccine is being considered as the most efficient strategy to curtail the ongoing pandemic. Following publication of genetic sequence of SARS-CoV-2, globally extensive research and development work has been in progress to develop a vaccine against the disease. The use of genetic engineering, recombinant technologies, and other computational tools has led to the expansion of several promising vaccine candidates. The range of technology platforms being evaluated, including virus-like particles, peptides, nucleic acid (DNA and RNA), recombinant proteins, inactivated virus, live attenuated viruses, and viral vectors (replicating and non-replicating) approaches, are striking features of the vaccine development strategies. Viral vectors, the next-generation vaccine platforms, provide a convenient method for delivering vaccine antigens into the host cell to induce antigenic proteins which can be tailored to arouse an assortment of immune responses, as evident from the success of smallpox vaccine and Ervebo vaccine against Ebola virus. As per the World Health Organization, till January 22, 2021, 14 viral vector vaccine candidates are under clinical development including 10 nonreplicating and four replicating types. Moreover, another 39 candidates based on viral vector platform are under preclinical evaluation. This review will outline the current developmental landscape and discuss issues that remain critical to the success or failure of viral vector vaccine candidates against COVID-19.

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Perspectives on RNA Vaccine Candidates for COVID-19

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.635245 ◽

2021 ◽

Vol 8 ◽

Author(s):

Pobitra Borah ◽

Pran Kishore Deb ◽

Nizar A. Al-Shar’i ◽

Lina A. Dahabiyeh ◽

Katharigatta N. Venugopala ◽

...

Keyword(s):

Viral Vectors ◽

Vaccine Development ◽

Lessons Learned ◽

Public Health Care ◽

World Health ◽

Genetic Sequencing ◽

Vaccine Candidates ◽

Clinical Investigations ◽

Current Outbreak ◽

Health Organization

With the current outbreak caused by SARS-CoV-2, vaccination is acclaimed as a public health care priority. Rapid genetic sequencing of SARS-CoV-2 has triggered the scientific community to search for effective vaccines. Collaborative approaches from research institutes and biotech companies have acknowledged the use of viral proteins as potential vaccine candidates against COVID-19. Nucleic acid (DNA or RNA) vaccines are considered the next generation vaccines as they can be rapidly designed to encode any desirable viral sequence including the highly conserved antigen sequences. RNA vaccines being less prone to host genome integration (cons of DNA vaccines) and anti-vector immunity (a compromising factor of viral vectors) offer great potential as front-runners for universal COVID-19 vaccine. The proof of concept for RNA-based vaccines has already been proven in humans, and the prospects for commercialization are very encouraging as well. With the emergence of COVID-19, mRNA-1273, an mRNA vaccine developed by Moderna, Inc. was the first to enter human trials, with the first volunteer receiving the dose within 10 weeks after SARS-CoV-2 genetic sequencing. The recent interest in mRNA vaccines has been fueled by the state of the art technologies that enhance mRNA stability and improve vaccine delivery. Interestingly, as per the “Draft landscape of COVID-19 candidate vaccines” published by the World Health Organization (WHO) on December 29, 2020, seven potential RNA based COVID-19 vaccines are in different stages of clinical trials; of them, two candidates already received emergency use authorization, and another 22 potential candidates are undergoing pre-clinical investigations. This review will shed light on the rationality of RNA as a platform for vaccine development against COVID-19, highlighting the possible pros and cons, lessons learned from the past, and the future prospects.

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SARS-CoV-2: The Path of Prevention and Control

Infectious Disorders - Drug Targets ◽

10.2174/1871526520666200520112848 ◽

2020 ◽

Vol 20 ◽

Cited By ~ 4

Author(s):

Amal A. Mohamed ◽

Nouran Mohamed ◽

Seham Mohamoud ◽

Fawkia E. Zahran ◽

Rania Abdelmonem Khattab ◽

...

Keyword(s):

Prevention And Control ◽

Vaccine Development ◽

Demographic Data ◽

World Health ◽

Effective Vaccine ◽

Healthy Population ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Health Organization ◽

And Control

: The 2019 coronavirus pandemic (COVID-19) continues to expand worldwide. Although the number of cases and the death rate among children and adolescents are reported to be low compared to adults, limited data have been reported. We urgently need to find treatment and vaccine to stop the epidemic. Vaccine development is in progress, but any approved and effective vaccine for COVID-19 is at least 12 to 18 months. The World Health Organization (WHO), the Center for Disease Control and Prevention (CDC), and the Food and Agriculture Organization (FAO) have issued instructions and strategies for containing COVID-19 outbreak to the general public, physicians, travelers and injured patients to follow so that the transmission to a healthy population can be prevented. In this review, we summarize demographic data, clinical characteristics, complications and outcomes and finally prevention and control of this serious pandemic.

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

Vaccines ◽

10.3390/vaccines9010039 ◽

2021 ◽

Vol 9 (1) ◽

pp. 39

Author(s):

Juanita Mellet ◽

Michael S. Pepper

Keyword(s):

Vaccine Development ◽

World Health ◽

Effective Vaccine ◽

Global Impact ◽

Simultaneous Testing ◽

The World ◽

Clinical Stages ◽

Health Organization ◽

High Level ◽

Modern Era

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.

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Identification of four linear B-cell epitopes on the SARS-CoV-2 spike protein able to elicit neutralizing antibodies

10.1101/2020.12.13.422550 ◽

2020 ◽

Author(s):

Lin Li ◽

Zhongpeng Zhao ◽

Xiaolan Yang ◽

WenDong Li ◽

Shaolong Chen ◽

...

Keyword(s):

B Cell ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Cell Epitope ◽

Effective Vaccine ◽

B Cell Epitopes ◽

S Protein ◽

The Public ◽

B Cell Epitope ◽

Linear B

SARS-CoV-2 unprecedentedly threatens the public health at worldwide level. There is an urgent need to develop an effective vaccine within a highly accelerated time. Here, we present the most comprehensive S-protein-based linear B-cell epitope candidate list by combining epitopes predicted by eight widely-used immune-informatics methods with the epitopes curated from literature published between Feb 6, 2020 and July 10, 2020. We find four top prioritized linear B-cell epitopes in the hotspot regions of S protein can specifically bind with serum antibodies from horse, mouse, and monkey inoculated with different SARS-CoV-2 vaccine candidates or a patient recovering from COVID-19. The four linear B-cell epitopes can induce neutralizing antibodies against both pseudo and live SARS-CoV-2 virus in immunized wild-type BALB/c mice. This study suggests that the four linear B-cell epitopes are potentially important candidates for serological assay or vaccine development.

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African Horse Sickness: A Review of Current Understanding and Vaccine Development

Viruses ◽

10.3390/v11090844 ◽

2019 ◽

Vol 11 (9) ◽

pp. 844 ◽

Cited By ~ 14

Author(s):

Susan J Dennis ◽

Ann E Meyers ◽

Inga I Hitzeroth ◽

Edward P Rybicki

Keyword(s):

Viral Vectors ◽

Reverse Genetics ◽

Vaccine Development ◽

Natural Infection ◽

Economic Consequences ◽

Sub Saharan Africa ◽

Current Understanding ◽

African Horse Sickness ◽

Virus Like Particle ◽

Sub Saharan

African horse sickness is a devastating disease that causes great suffering and many fatalities amongst horses in sub-Saharan Africa. It is caused by nine different serotypes of the orbivirus African horse sickness virus (AHSV) and it is spread by Culicoid midges. The disease has significant economic consequences for the equine industry both in southern Africa and increasingly further afield as the geographic distribution of the midge vector broadens with global warming and climate change. Live attenuated vaccines (LAV) have been used with relative success for many decades but carry the risk of reversion to virulence and/or genetic re-assortment between outbreak and vaccine strains. Furthermore, the vaccines lack DIVA capacity, the ability to distinguish between vaccine-induced immunity and that induced by natural infection. These concerns have motivated interest in the development of new, more favourable recombinant vaccines that utilize viral vectors or are based on reverse genetics or virus-like particle technologies. This review summarizes the current understanding of AHSV structure and the viral replication cycle and also evaluates existing and potential vaccine strategies that may be applied to prevent or control the disease.

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