scholarly journals SARS-CoV-2 immunity and an overview of the COVID-19 vaccines

2021 ◽  
Vol 72 (3) ◽  
pp. 20-29
Author(s):  
Miloš Marković
Keyword(s):  
Immune Response ◽  
Mass Vaccination ◽  
Efficacy And Safety ◽  
Global Level ◽  
Post Vaccination ◽  
Degree Of Protection ◽  
Open Questions ◽  
Short Period ◽  
Open Issues

The remarkable development of a large number of vaccines against COVID-19 in a very short period of time represents one of the greatest successes of medicine and science in history, and mass vaccination at the global level will be crucial for prevention and mitigation of COVID-19. However, there are still numerous open questions about the vaccines, and the protection they provide, and answers to those questions will not only help to control this pandemic, but they will also prepare us to react better in case of future outbreaks. This review will present the latest findings on the immune response to SARS-CoV-2 and give an update on COVID-19 immunity. It will also provide an overview of the most important vaccines against COVID-19, especially those available in Serbia, with an emphasis on their immunogenicity, efficacy and safety, as well as the platforms used for their development. In addition, a special attention will be given to open issues related to immunization against COVID-19, such as the duration of post-vaccination immunity, the degree of protection against new virus variants and the need for booster doses and mixing and matching of different COVID-19 vaccines.

scholarly journals Use of Proteins Identified through a Functional Genomic Screen To Develop a Protein Subunit Vaccine That Provides Significant Protection against Virulent Streptococcus suis in Pigs

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Susan L. Brockmeier ◽  
Crystal L. Loving ◽  
Tracy L. Nicholson ◽  
Jinhong Wang ◽  
Sarah E. Peters ◽  
...  
Keyword(s):  
Immune Response ◽  
Vaccine Trial ◽  
Streptococcus Suis ◽  
Protein Subunit ◽  
Content Type ◽  
Degree Of Protection ◽  
Wide Range ◽  
Associated Proteins ◽  
Clinical Protection ◽  
Cellular Immune

ABSTRACT Streptococcus suis is a bacterium that is commonly carried in the respiratory tract and that is also one of the most important invasive pathogens of swine, commonly causing meningitis, arthritis, and septicemia. Due to the existence of many serotypes and a wide range of immune evasion capabilities, efficacious vaccines are not readily available. The selection of S. suis protein candidates for inclusion in a vaccine was accomplished by identifying fitness genes through a functional genomics screen and selecting conserved predicted surface-associated proteins. Five candidate proteins were selected for evaluation in a vaccine trial and administered both intranasally and intramuscularly with one of two different adjuvant formulations. Clinical protection was evaluated by subsequent intranasal challenge with virulent S. suis . While subunit vaccination with the S. suis proteins induced IgG antibodies to each individual protein and a cellular immune response to the pool of proteins and provided substantial protection from challenge with virulent S. suis , the immune response elicited and the degree of protection were dependent on the parenteral adjuvant given. Subunit vaccination induced IgG reactive against different S. suis serotypes, indicating a potential for cross protection.

scholarly journals The Analysis of Live-Attenuated Piscirickettsia salmonis Vaccine Reveals the Short-Term Upregulation of Innate and Adaptive Immune Genes in Atlantic Salmon (Salmo salar): An In Situ Open-Sea Cages Study

2021 ◽  
Vol 9 (4) ◽  
pp. 703
Author(s):  
Deborah Vargas ◽  
Eva Vallejos-Vidal ◽  
Sebastián Reyes-Cerpa ◽  
Aarón Oyarzún-Arrau ◽  
Claudio Acuña-Castillo ◽  
...  
Keyword(s):  
Immune Response ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Cellular Response ◽  
Short Term ◽  
Live Attenuated Vaccine ◽  
Gene Markers ◽  
Post Vaccination ◽  
Atlantic Salmon Salmo Salar ◽  
Piscirickettsia Salmonis

Piscirickettsia salmonis, the etiological agent of the Salmon Rickettsial Septicemia (SRS), is one the most serious health problems for the Chilean salmon industry. Typical antimicrobial strategies used against P. salmonis include antibiotics and vaccines, but these applications have largely failed. A few years ago, the first attenuated-live vaccine against SRS (ALPHA JECT LiVac® SRS vaccine) was released to the market. However, there is no data about the agents involved in the activation of the immune response induced under field conditions. Therefore, in this study we evaluated the expression profile of a set of gene markers related to innate and adaptive immunity in the context of a cellular response in Atlantic salmon (Salmo salar) reared under productive farm conditions and immunized with a live-attenuated vaccine against P. salmonis. We analyzed the expression at zero, 5-, 15- and 45-days post-vaccination (dpv). Our results reveal that the administration of the attenuated live SRS LiVac vaccine induces a short-term upregulation of the cellular-mediated immune response at 5 dpv modulated by the upregulation of ifnα, ifnγ, and the cd4 and cd8α T cell surface markers. In addition, we also registered the upregulation of il-10 and tgfβ. Altogether, the results suggest that a balanced activation of the immune response took place only at early times post-vaccination (5 dpv). The scope of this short-term upregulation of the cellular-mediated immune response against a natural outbreak in fish subjected to productive farm conditions deserves further research.

scholarly journals Physicochemical Characterization Cascade of Nanoadjuvant–Antigen Systems for Improving Vaccines

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 544
Author(s):  
Giuditta Guerrini ◽  
Antonio Vivi ◽  
Sabrina Gioria ◽  
Jessica Ponti ◽  
Davide Magrì ◽  
...  
Keyword(s):  
Immune Response ◽  
Protein Structure ◽  
Physicochemical Properties ◽  
Physicochemical Characterization ◽  
Protein Antigen ◽  
Efficacy And Safety

Adjuvants have been used for decades to enhance the immune response to vaccines, in particular for the subunit-based adjuvants. Physicochemical properties of the adjuvant-protein antigen complexes, such as size, morphology, protein structure and binding, influence the overall efficacy and safety of the vaccine. Here we show how to perform an accurate physicochemical characterization of the nanoaluminum–ovalbumin complex. Using a combination of existing techniques, we developed a multi-staged characterization strategy based on measurements of increased complexity. This characterization cascade has the advantage of being very flexible and easily adaptable to any adjuvant-protein antigen combinations. It will contribute to control the quality of antigen–adjuvant complexes and immunological outcomes, ultimately leading to improved vaccines.

scholarly journals The Koala Immune Response to Chlamydial Infection and Vaccine Development—Advancing Our Immunological Understanding

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 380
Author(s):  
Bonnie L Quigley ◽  
Peter Timms
Keyword(s):  
Immune Response ◽  
Chlamydial Infection ◽  
Vaccine Development ◽  
Interleukin 17 ◽  
Phascolarctos Cinereus ◽  
Post Vaccination ◽  
Research Systems ◽  
Cytokine Levels ◽  
Nucleic Acid Assay ◽  
Immunological Research

Chlamydia is a significant pathogen for many species, including the much-loved Australian marsupial, the koala (Phascolarctos cinereus). To combat this situation, focused research has gone into the development and refinement of a chlamydial vaccine for koalas. The foundation of this process has involved characterising the immune response of koalas to both natural chlamydial infection as well as vaccination. From parallels in human and mouse research, it is well-established that an effective anti-chlamydial response will involve a balance of cell-mediated Th1 responses involving interferon-gamma (IFN-γ), humoral Th2 responses involving systemic IgG and mucosal IgA, and inflammatory Th17 responses involving interleukin 17 (IL-17) and neutrophils. Characterisation of koalas with chlamydial disease has shown increased expression within all three of these major immunological pathways and monitoring of koalas’ post-vaccination has detected further enhancements to these key pathways. These findings offer optimism that a chlamydial vaccine for wider distribution to koalas is not far off. Recent advances in marsupial genetic knowledge and general nucleic acid assay technology have moved koala immunological research a step closer to other mammalian research systems. However, koala-specific reagents to directly assay cytokine levels and cell-surface markers are still needed to progress our understanding of koala immunology.

scholarly journals Association of immune response with efficacy and safety outcomes in adults with phenylketonuria administered pegvaliase in phase 3 clinical trials

EBioMedicine ◽  
2018 ◽  
Vol 37 ◽  
pp. 366-373 ◽  
Author(s):  
Soumi Gupta ◽  
Kelly Lau ◽  
Cary O. Harding ◽  
Gillian Shepherd ◽  
Ryan Boyer ◽  
...  
Keyword(s):  
Immune Response ◽  
Clinical Trials ◽  
Efficacy And Safety ◽  
Phase 3 ◽  
Safety Outcomes

scholarly journals Randomized, double-blinded, controlled non-inferiority trials evaluating the immunogenicity and safety of fractional doses of Yellow Fever vaccines in Kenya and Uganda

2019 ◽  
Vol 4 ◽  
pp. 182 ◽  
Author(s):  
Derick Kimathi ◽  
Aitana Juan ◽  
Philip Bejon ◽  
Rebecca F. Grais ◽  
George M. Warimwe ◽  
...  
Keyword(s):  
Immune Response ◽  
Randomized Controlled Trials ◽  
Yellow Fever ◽  
Vaccine Dose ◽  
World Health ◽  
Yellow Fever Vaccine ◽  
Controlled Trials ◽  
Post Vaccination ◽  
Randomized Controlled ◽  
Link Type

Introduction: Yellow fever is endemic in specific regions of sub-Saharan Africa and the Americas, with recent epidemics occurring on both continents. The yellow fever vaccine is effective, affordable and safe, providing life-long immunity following a single dose vaccination. However, the vaccine production process is slow and cannot be readily scaled up during epidemics. This has led the World Health Organization (WHO) to recommend the use of fractional doses as a dose-sparing strategy during epidemics, but there are no randomized controlled trials of fractional yellow fever vaccine doses in Africa. Methods and analysis: We will recruit healthy adult volunteers, adults living with HIV, and children to a series of randomized controlled trials aiming to determine the immunogenicity and safety of fractional vaccine doses in comparison to the standard vaccine dose. The trials will be conducted across two sites; Kilifi, Kenya and Mbarara, Uganda. Recruited participants will be randomized to receive fractional or standard doses of yellow fever vaccine. Scheduled visits will include blood collection for serum and peripheral blood mononuclear cells (PBMCs) before vaccination and on various days – up to 2 years – post-vaccination. The primary outcome is the rate of seroconversion as measured by the plaque reduction neutralization test (PRNT50) at 28 days post-vaccination. Secondary outcomes include antibody titre changes, longevity of the immune response, safety assessment using clinical data, the nature and magnitude of the cellular immune response and post-vaccination control of viremia by vaccine dose. Ethics and dissemination: The clinical trial protocols have received approval from the relevant institutional ethics and regulatory review committees in Kenya and Uganda, and the WHO Ethics Review Committee. The research findings will be disseminated through open-access publications and presented at relevant conferences and workshops. Registration: ClinicalTrials.gov NCT02991495 (registered on 13 December 2016) and NCT04059471 (registered on 15 August 2019).

scholarly journals The resurgence risk of COVID-19 in the presence of immunity waning and ADE effect: a mathematical modelling study

2021 ◽  
Author(s):  
Weike Zhou ◽  
Biao Tang ◽  
Yao Bai ◽  
Yiming Shao ◽  
Yanni Xiao ◽  
...  
Keyword(s):  
Mainland China ◽  
Population Level ◽  
Mass Vaccination ◽  
Low Risk ◽  
Vaccination Program ◽  
Post Vaccination ◽  
Catching Up ◽  
Vaccination Period ◽  
Transmission Ability

Since the end of 2020, the mass vaccination has been actively promoted and seemed to be effective to bring the COVID-19 pandemic under control. However, the fact of immunity waning and the possible existence of antibody-dependent enhancement (ADE) make the situation uncertain. We developed a dynamic model of COVID-19 incorporating vaccination and immunity waning, which was calibrated by using the data of accumulative vaccine doses administered and the COVID-19 epidemic in 2020 in mainland China. We explored how long the current vaccination program can prevent China in a low risk of resurgence, and how ADE affects the long-term trajectory of COVID-19 epidemics. The prediction suggests that the vaccination coverage with at least one dose reach 95.87%, and with two-doses reach 77.92% on August 31, 2021. However, even with the mass vaccination, randomly introducing infected cases in the post-vaccination period can result in large outbreaks quickly in the presence of immunity waning, particularly for SARS-CoV-2 variants with higher transmission ability. The results showed that with the current vaccination program and a proportion of 50% population wearing masks, mainland China can be protected in a low risk of resurgence till 2023/01/18. However, ADE effect and higher transmission ability for variants would significantly shorten the protective period for more than 1 year. Furthermore, intermittent outbreaks can occur while the peak values of the subsequential outbreaks are decreasing, meaning that subsequential outbreaks boosted the immunity in the population level, which further indicating that catching-up vaccination program can help to mitigate the possible outbreaks, even avoid the outbreaks. The findings reveal that integrated effects of multiple factors, including immunity waning, ADE, relaxed interventions, and higher transmission ability of variants, make the control of COVID-19 much more difficult. We should get ready for a long struggle with COVID-19, and should not totally rely on COVID-19 vaccine.

scholarly journals COVID19 vaccine type and humoral immune response in patients receiving dialysis

2021 ◽  
Author(s):  
Pablo Garcia ◽  
Shuchi Anand ◽  
Jialin Han ◽  
Maria Montez-Rath ◽  
Sumi Sun ◽  
...  
Keyword(s):  
Immune Response ◽  
Antibody Index ◽  
Igg Antibody ◽  
Post Vaccination ◽  
Humoral Immune ◽  
Vaccination Response ◽  
Vaccine Type ◽  
Igg Index ◽  
Impaired Immune Response ◽  
Index Value

Background Patients on dialysis vaccinated with the attenuated adenovirus SARS-CoV-2 vaccine might mount an impaired response to vaccination. Methods We evaluated the humoral vaccination response among 2,099 fully vaccinated patients receiving dialysis. We used commercially available assays (Siemens) to assess prevalence of no response or diminished response to COVID-19 vaccination by vaccine type. We defined no seroconversion as lack of change from negative to positive in total RBD Ig antibody, no detectable response on semiquantitative RBD IgG antibody (index value <1) as no RBD IgG response, and a semiquantitative RBD IgG index value <10 as diminished RBD IgG response Results Of the 2,099 fully vaccinated patients on dialysis, the proportion receiving the mRNA1273, BNT162b2, and Ad26.COV2.S were 62% (n=1316), 20% (n=416) and 18% (n=367), respectively. A third (33.3%) of patients receiving the attenuated adenovirus Ad26.COV2.S vaccine failed to seroconvert and an additional 36% had no detectable or diminished IgG response even 28-60 days post vaccination. Conclusions One in three fully vaccinated patients receiving dialysis had evidence of an impaired immune response to the attenuated adenovirus Ad26.COV2.S vaccine.

scholarly journals Evaluation of Anti-HBs Antibody Immune Response against Hepatitis B virus in Vaccinated People in а North-eastern Bulgaria Region

Folia Medica ◽  
2019 ◽  
Vol 61 (4) ◽  
pp. 572-578
Author(s):  
Denitsa T. Tsaneva-Damyanova ◽  
Liliya I. Ivanova ◽  
Silviya N. Pavlova ◽  
Svetlana B. Todorova ◽  
Tsvetelina K. Popova
Keyword(s):  
Immune Response ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Age Groups ◽  
University Hospital ◽  
Human Pathogens ◽  
Serum Samples ◽  
Post Vaccination ◽  
B Virus ◽  
Mass Immunization

Introduction: Hepatitis B virus (HBV) is one of the most significant human pathogens responsible for a huge number of acute and chronic liver infectious diseases worldwide. Aim: To find the duration of post-vaccination immune response in individuals allocated to five age groups from 6 months to 20 years. Materials and methods: All tested subjects were born between 1999 and 2018 and therefore covered by the compulsory vaccination program against hepatitis B. For the serological marker anti-HBs Ab we investigated 449 serum samples taken from ambulatory people and patients of St Marina University Hospital in Varna. Results: A positive antibody response (anti-HBs Ab > 10 mIU/ml) was reported in 79.7% (n = 51) of the group of subjects up to one year old, in 70.0% (n = 196) of the subjects in the age range 1 year/1 month to 15 years, and in 39.3% (n = 33) of the subjects 15 years/1 month to 20 years old. Female sex had a better post-vaccination response than male sex with statistically significant relationship between sex and anti-HBs Ab titer (&chi;2 = 24.76, p <0.01). Conclusions: Regardless of the mass immunization against HBV in Bulgaria, the relative share of chronic HBV infections does not show a downward trend. Therefore, it is very important to study the duration of the post-vaccination immune response by demonstrating the anti-HBs antibodies and to apply a booster dose from the vaccine if needed.

scholarly journals On the safety and effectiveness of COVID-19 vaccines, certainties and uncertainties

2021 ◽  
Vol 9 (4) ◽  
pp. 16-24
Author(s):  
Ana Cecilia Amado Xavier de Oliveira ◽  
◽  
Isabella Fernandes Delgado ◽  
Francisco José Roma Paumgartten ◽  
◽  
...  
Keyword(s):  
Observational Studies ◽  
Clinical Trial Data ◽  
Vaccine Safety ◽  
Efficacy And Safety ◽  
Phase 3 ◽  
Degree Of Protection ◽  
Overwhelming Evidence ◽  
The Impact ◽  
Site Pain

Introduction: The COVID-19 vaccines in use (inactivaded virus, encapsulated m-RNA, non-replicating adenovirus-vectored DNA) were clinically tested in randomized placebocontrolled phase-3 studies. Objective: To address certainties and uncertainties about safety and effectiveness of COVID-19 vaccines that were approved for use in various countries. Method: The evidence provided by clinical studies on the efficacy and safety of COVID-19 vaccines was critically appraised. Results: COVID-19 vaccines proved to be efficacious and safe in clinical trials. Adverse events were mostly those of minor severity commonly noted with other vaccines such as injection site pain, mild flu-like symptoms, headache and asthenia. Although being very rare, anaphylaxis-like reactions were noted with mRNA vaccines. Uncertainties regarding vaccine effectiveness refer mainly to the (long-term) duration of immunity provided by vaccination, the degree of protection conferred to elderly people, and how effective vaccines are against emerging SARS-CoV-2 variants. There are few uncertainties about vaccine safety including the absence of clinical trial data in pregnant women (and the impact on the unborn child), children and adolescents. Conclusions: Notwithstanding the knowledge gaps about effectiveness and safety of COVID-19 vaccines (to be further addressed by observational studies), there is overwhelming evidence that public health benefits of vaccination by far outweigh any foreseeable risk.

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