scholarly journals Ultra-low dose immunization and multi-component vaccination strategies enhance protection against malaria in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katharine A. Collins ◽  
Florian Brod ◽  
Rebecca Snaith ◽  
Marta Ulaszewska ◽  
Rhea J. Longley ◽  
...  
Keyword(s):  
Viral Vectors ◽  
Low Dose ◽  
Protective Efficacy ◽  
Vaccine Dose ◽  
Effective Vaccine ◽  
Phase 3 ◽  
Partial Protection ◽  
Potential Efficacy ◽  
Transgenic Parasites ◽  
Dose Vaccine

AbstractAn effective vaccine would be a valuable tool for malaria control and elimination; however, the leading malaria vaccine in development, RTS,S/AS01, provided only partial protection in a Phase 3 trial. R21 is a next-generation RTS,S-like vaccine. We have previously shown in mice that R21 administered in Matrix-M is highly immunogenic, able to elicit complete protection against sporozoite challenge, and can be successfully administered with TRAP based viral-vectors resulting in enhanced protection. In this study, we developed a novel, GMP-compatible purification process for R21, and evaluated the immunogenicity and protective efficacy of ultra-low doses of both R21 and RTS,S when formulated in AS01. We demonstrated that both vaccines are highly immunogenic and also elicit comparable high levels of protection against transgenic parasites in BALB/c mice. By lowering the vaccine dose there was a trend for increased immunogenicity and sterile protection, with the highest dose vaccine groups achieving the lowest efficacy (50% sterile protection). We also evaluated the ability to combine RTS,S/AS01 with TRAP based viral-vectors and observed concurrent induction of immune responses to both antigens with minimal interference when mixing the vaccines prior to administration. These studies suggest that R21 or RTS,S could be combined with viral-vectors for a multi-component vaccination approach and indicate that low dose vaccination should be fully explored in humans to maximize potential efficacy.

scholarly journals Covid-19 vaccine trials and ethics: Protection delayed is protection denied

2020 ◽  
pp. 01-03
Author(s):  
T Jacob John ◽  
Dhanya Dharmapalan
Keyword(s):  
Large Scale ◽  
Protective Efficacy ◽  
Informed Choice ◽  
Effective Vaccine ◽  
Compassionate Use ◽  
Vaccine Research ◽  
Phase 3 ◽  
Vaccine Candidates ◽  
Risk Of Death ◽  
Vaccine Trials

Abstract The Covid-19 pandemic is raging, taking a heavy toll of lives and livelihoods. The need for safe and effective vaccine(s) is urgent. Vaccine research has progressed rapidly and a few vaccine candidates have passed trial Phases 1 and 2, confirming reasonable safety and immunogenicity parameters. They are ready for large scale Phase 3 trials to quantify protective efficacy, if any, and to detect uncommon but serious adverse effects, if any. These developments present unprecedented opportunities and challenges, scientific and ethical. Globally hundreds die every day due to Covid-19, and emergency/compassionate use of vaccine candidates that are ready for Phase 3 trials are likely to save lives. We perceive an ethical imperative to allow such vaccination for those at high risk of death who voluntarily make such an informed choice – for them protection delayed will be tantamount to protection denied.

scholarly journals A Zigzag but Upward Way to Develop an HIV-1 Vaccine

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 511
Author(s):  
Ziyu Wen ◽  
Caijun Sun
Keyword(s):  
Viral Vectors ◽  
Protective Efficacy ◽  
Effective Vaccine ◽  
Immunological Parameters ◽  
Recombinant Viruses ◽  
Correlates Of Protection ◽  
Immune Correlates ◽  
Immunodeficiency Virus ◽  
Hiv 1

After decades of its epidemic, the human immunodeficiency virus type 1 (HIV-1) is still rampant worldwide. An effective vaccine is considered to be the ultimate strategy to control and prevent the spread of HIV-1. To date, hundreds of clinical trials for HIV-1 vaccines have been tested. However, there is no HIV-1 vaccine available yet, mostly because the immune correlates of protection against HIV-1 infection are not fully understood. Currently, a variety of recombinant viruses-vectored HIV-1 vaccine candidates are extensively studied as promising strategies to elicit the appropriate immune response to control HIV-1 infection. In this review, we summarize the current findings on the immunological parameters to predict the protective efficacy of HIV-1 vaccines, and highlight the latest advances on HIV-1 vaccines based on viral vectors.

scholarly journals Development of an Inactivated Vaccine against SARS CoV-2

Vaccines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1266
Author(s):  
Shaikh Terkis Islam Pavel ◽  
Hazel Yetiskin ◽  
Muhammet Ali Uygut ◽  
Ahmet Furkan Aslan ◽  
Günsu Aydın ◽  
...  
Keyword(s):  
Viral Vectors ◽  
Vaccine Candidate ◽  
Protective Efficacy ◽  
Safety Evaluation ◽  
Preclinical Development ◽  
Phase 3 ◽  
Strong Immune Response ◽  
University Of Oxford ◽  
Current Outbreak ◽  
Global Threat

The rapid spread of SARS-CoV-2 with its mutating strains has posed a global threat to safety during this COVID-19 pandemic. Thus far, there are 123 candidate vaccines in human clinical trials and more than 190 candidates in preclinical development worldwide as per the WHO on 1 October 2021. The various types of vaccines that are currently approved for emergency use include viral vectors (e.g., adenovirus, University of Oxford/AstraZeneca, Gamaleya Sputnik V, and Johnson & Johnson), mRNA (Moderna and Pfizer-BioNTech), and whole inactivated (Sinovac Biotech and Sinopharm) vaccines. Amidst the emerging cases and shortages of vaccines for global distribution, it is vital to develop a vaccine candidate that recapitulates the severe and fatal progression of COVID-19 and further helps to cope with the current outbreak. Hence, we present the preclinical immunogenicity, protective efficacy, and safety evaluation of a whole-virion inactivated SARS-CoV-2 vaccine candidate (ERUCoV-VAC) formulated in aluminium hydroxide, in three animal models, BALB/c mice, transgenic mice (K18-hACE2), and ferrets. The hCoV-19/Turkey/ERAGEM-001/2020 strain was used for the safety evaluation of ERUCoV-VAC. It was found that ERUCoV-VAC was highly immunogenic and elicited a strong immune response in BALB/c mice. The protective efficacy of the vaccine in K18-hACE2 showed that ERUCoV-VAC induced complete protection of the mice from a lethal SARS-CoV-2 challenge. Similar viral clearance rates with the safety evaluation of the vaccine in upper respiratory tracts were also positively appreciable in the ferret models. ERUCoV-VAC has been authorized by the Turkish Medicines and Medical Devices Agency and has now entered phase 3 clinical development (NCT04942405). The name of ERUCoV-VAC has been changed to TURKOVAC in the phase 3 clinical trial.

scholarly journals Low-Dose Ad26.COV2.S Protection Against SARS-CoV-2 Challenge in Rhesus Macaques

2021 ◽  
Author(s):  
Xuan He ◽  
Abishek Chandrashekar ◽  
Roland Zahn ◽  
Frank Wegmann ◽  
Jingyou Yu ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Low Dose ◽  
Protective Efficacy ◽  
Rhesus Macaques ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Upper Respiratory Tract ◽  
Nasal Swabs ◽  
Show Evidence ◽  
Antibody Titers

AbstractWe previously reported that a single immunization with an adenovirus serotype 26 (Ad26) vector-based vaccine expressing an optimized SARS-CoV-2 spike (Ad26.COV2.S) protected rhesus macaques against SARS-CoV-2 challenge. In this study, we evaluated the immunogenicity and protective efficacy of reduced doses of Ad26.COV2.S. 30 rhesus macaques were immunized once with 1×1011, 5×1010, 1.125×1010, or 2×109 vp Ad26.COV2.S or sham and were challenged with SARS-CoV-2 by the intranasal and intratracheal routes. Vaccine doses as low as 2×109 vp provided robust protection in bronchoalveolar lavage, whereas doses of 1.125×1010 vp were required for protection in nasal swabs. Activated memory B cells as well as binding and neutralizing antibody titers following vaccination correlated with protective efficacy. At suboptimal vaccine doses, viral breakthrough was observed but did not show evidence of virologic, immunologic, histopathologic, or clinical enhancement of disease compared with sham controls. These data demonstrate that a single immunization with a relatively low dose of Ad26.COV2.S effectively protected against SARS-CoV-2 challenge in rhesus macaques. Moreover, our findings show that a higher vaccine dose may be required for protection in the upper respiratory tract compared with the lower respiratory tract.

scholarly journals Enhancing the Protective Immune Response against Botulism

2013 ◽  
Vol 81 (7) ◽  
pp. 2638-2644 ◽  
Author(s):  
Amanda Przedpelski ◽  
William H. Tepp ◽  
Abby R. Kroken ◽  
Zhuji Fu ◽  
Jung-Ja P. Kim ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Low Dose ◽  
Binding Capacity ◽  
Vaccine Dose ◽  
Binding Pocket ◽  
Protective Immune Response ◽  
High Dose ◽  
Control And Prevention ◽  
Dose Vaccine

ABSTRACTThe need for a vaccine against botulism has increased since the discontinuation of the pentavalent (ABCDE) botulinum toxoid vaccine by the Centers for Disease Control and Prevention. The botulinum toxins (BoNTs) are the primary virulence factors and vaccine components against botulism. BoNTs comprise three domains which are involved in catalysis (LC), translocation (HCT), and host receptor binding (HCR). Recombinant HCR subunits have been used to develop the next generation of BoNT vaccines. Using structural studies and the known entry properties of BoNT/A, an HCR subunit vaccine against BoNT/A that contained the point mutation W1266A within the ganglioside binding pocket was designed. HCR/A(W1266A) did not enter primary neurons, and the crystal structure of HCR/A(W1266A) was virtually identical to that of wild-type HCR/A. Using a mouse model, experiments were performed using a high-dose vaccine and a low-dose vaccine. At a high vaccine dose, HCR/A and HCR/A(W1266A) elicited a protective immune response to BoNT/A challenge. At the low-dose vaccination, HCR/A(W1266A) was a more protective vaccine than HCR/A. α-HCR IgG titers correlated with protection from BoNT challenge, although titers to block HCR/A entry were greater in serum in HCR/A-vaccinated mice than in HCR/A(W1266A)-vaccinated mice. This study shows that removal of receptor binding capacity enhances potency of the subunit HCR vaccine. Vaccines that lack receptor binding capacity have the added property of limited off-target toxicity.

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

Pharmaceutics ◽  
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.

scholarly journals SARS-CoV-2 vaccines strategies: a comprehensive review of phase 3 candidates

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Nikolaos C. Kyriakidis ◽  
Andrés López-Cortés ◽  
Eduardo Vásconez González ◽  
Alejandra Barreto Grimaldos ◽  
Esteban Ortiz Prado
Keyword(s):  
Neutralizing Antibodies ◽  
Large Scale ◽  
Vaccine Development ◽  
Rna Virus ◽  
Protein S ◽  
Effective Vaccine ◽  
Phase 3 ◽  
Vaccine Candidates ◽  
Advantages And Disadvantages ◽  
The World

AbstractThe new SARS-CoV-2 virus is an RNA virus that belongs to the Coronaviridae family and causes COVID-19 disease. The newly sequenced virus appears to originate in China and rapidly spread throughout the world, becoming a pandemic that, until January 5th, 2021, has caused more than 1,866,000 deaths. Hence, laboratories worldwide are developing an effective vaccine against this disease, which will be essential to reduce morbidity and mortality. Currently, there more than 64 vaccine candidates, most of them aiming to induce neutralizing antibodies against the spike protein (S). These antibodies will prevent uptake through the human ACE-2 receptor, thereby limiting viral entrance. Different vaccine platforms are being used for vaccine development, each one presenting several advantages and disadvantages. Thus far, thirteen vaccine candidates are being tested in Phase 3 clinical trials; therefore, it is closer to receiving approval or authorization for large-scale immunizations.

scholarly journals Development of COVID-19 vaccines utilizing gene therapy technology

2021 ◽  
Author(s):  
Hironori Nakagami
Keyword(s):  
Viral Vectors ◽  
High Efficiency ◽  
Genetic Disorders ◽  
Rapid Development ◽  
Adenovirus Vector ◽  
Phase 3 ◽  
Double Blind ◽  
Time Period ◽  
Short Period ◽  
Long Time

Abstract There is currently an outbreak of respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronavirus disease 2019 (COVID-19) is caused by infection with SARS-CoV-2. Individuals with COVID-19 have symptoms that are usually asymptomatic or mild in most initial cases. However, in some cases, moderate and severe symptoms have been observed with pneumonia. Many companies are developing COVID-19 vaccine candidates using different technologies that are classified into four groups (intact target viruses, proteins, viral vectors and nucleic acids). For rapid development, RNA vaccines and adenovirus vector vaccines have been urgently approved, and their injection has already started across the world. These types of vaccine technologies have been developed over more than 20 years using translational research for use against cancer or diseases caused by genetic disorders but the COVID-19 vaccines are the first licensed drugs to prevent infectious diseases using RNA vaccine technology. Although these vaccines are highly effective in preventing COVID-19 for a short period, safety and efficiency evaluations should be continuously monitored over a long time period. As the time of writing, more than 10 projects are now in phase 3 to evaluate the prevention of infection in double-blind studies. Hopefully, several projects may be approved to ensure high-efficiency and safe vaccines.

Abstract T P48: Intravenous Thrombolysis Using Low-Dose Alteplase for Nonagenarians with Acute Ischemic Stroke: The SAMURAI rtPA Registry

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Mikito Hayakawa ◽  
Masatoshi Koga ◽  
Shoichiro Sato ◽  
Shoji Arihiro ◽  
Yoshiaki Shiokawa ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Low Dose ◽  
Intravenous Thrombolysis ◽  
Functional Independence ◽  
Efficacy And Safety ◽  
Multivariate Adjustment ◽  
Potential Efficacy ◽  
Symptomatic Intracranial Hemorrhage ◽  
Baseline Characteristics

Objective: Although intravenous thrombolysis (IVT) using alteplase for octogenarians with acute ischemic stroke becomes relatively familiar, it is unclear whether IVT for nonagenarians is a futile intervention. The purpose of this study is to clarify the efficacy and safety of IVT using low-dose alteplase (0.6 mg/kg) for nonagenarians compared with octogenarians. Methods: Stroke Acute Management with Urgent Risk-factor Assessment and Improvement (SAMURAI) rtPA registry retrospectively collected 600 consecutive acute stroke patients receiving IVT from 10 Japanese stroke centers between October 2005 and July 2008. We extracted all octogenarians (O group) and nonagenarians (N group) from the registry. We compared baseline characteristics, symptomatic intracranial hemorrhage (SICH), and 3-month outcomes between the groups. 3-month outcomes include; functional independence (FI) defined as a mRS score 0-2, good outcome (GO) as a mRS score 0-2 or same as the premorbid mRS, poor outcome (PO) defined as a mRS score 5-6, and death. Results: Twenty-five nonagenarians (mean age, 93 years) and 124 octogenarians (mean age, 84 years) were included. N group was more female-predominant (76% versus 56%, p=0.06) and premorbidly dependent (44% versus 14%, p<0.001) than O group. There were no significant differences of median baseline NIHSS score (16 versus 14, p=0.95) and Alberta Stroke Program Early CT Score (9 versus 9, p=0.36) between the groups. The rate of FI tended to be lower in N group than O group (16% versus 36%, p=0.06), otherwise, the differences of the rates of GO (28% versus 37%, p=0.39), PO (40% versus 36%, p=0.73), death (20% versus 11%, p=0.23) and SICH (0% versus 2.4%, p=1.00) were not significant between the groups. In comparison with O group, N group was not associated with 3-month clinical outcomes (FI; OR 0.61; 95% CI, 0.15-2.42, GO; 0.98; 0.31-3.07, PO; 0.63; 0.15-2.70, death; 3.18; 0.62-16.3) and SICH (0.68; 0.17-2.69) after multivariate adjustment. Conclusions: IVT using low-dose alteplase for N group resulted in less frequent achievement of FI mainly because of more premorbid dependency than O group, however, showed at least a similar safety and a potential efficacy.

scholarly journals Development of Novel Protective Polyvalent Irradiated Pseudomonas aeruginosa Vaccine for Immuno-Compromised Patients

2021 ◽  
Vol 16 ◽  
pp. 1-10
Author(s):  
Manal M.E. Ahmed ◽  
Jakeen Eljakee ◽  
Tarek Mahran
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Protective Efficacy ◽  
Challenge Test ◽  
Opportunistic Pathogen ◽  
Effective Vaccine ◽  
The Novel ◽  
Therapeutic Approaches ◽  
Promising Strategy ◽  
Antigenic Expression ◽  
Compromised Patients

Pseudomonas aeruginosa is an opportunistic pathogen affecting immuno-compromised patients; however, no effective vaccine is currently available in the market. Here, we developed novel polyvalent irradiated P. aeruginosa vaccine using cobalt 60 that inhibited pathogen viability but retained antigenic expression functionally. Mice were vaccinated by the developed vaccine by intranasal, intramuscular and subcutaneous route of administration followed by challenge test. The protective efficacy of the novel vaccine reached up to 95%. This significant protection was mainly associated with measurable antiserum opsonic killing activity. In conclusion, the novel vaccine provides a promising strategy of both prophylactic and therapeutic approaches for immuno-compromised patients against MDR P. aeruginosa.

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