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Biologicals : Journal of the... May 2023The treatment of Klebsiella pneumoniae is faced with challenges demanding the development of a vaccination strategy. However, no approved and globally available vaccine... (Review)
Review
The treatment of Klebsiella pneumoniae is faced with challenges demanding the development of a vaccination strategy. However, no approved and globally available vaccine exists yet. This study aimed to systematically review all published data on K. pneumoniae vaccines in animal models. Without time restrictions, electronic databases were searched using appropriate keywords. The retrieved studies were screened and the data of those that matched our inclusion criteria were collected and analyzed. In total, 2027 records were retrieved; of which 35 studies were included for systematic review. The most frequently used animal model was BALB/c mice. Proteins, polysaccharides, and their combinations (conjugates) were the most common vaccine candidates used. The amount of antigen, the route used for immunization, and the challenge strategy was varying in the studies and were chosen based on several factors such as the animal model, the type of antigen, and the schedule of immunization. Almost all studies claimed that their vaccine was effective/protective, indicated by increasing survival rate, reducing organ bacterial load, and eliciting protective antibody and/or cytokine responses. Altogether, the information presented here will assist researchers to have a better look at the K. pneumoniae vaccine candidates and to take more effective steps in the future.
Topics: Animals; Mice; Bacterial Vaccines; Immunization; Klebsiella Infections; Klebsiella pneumoniae; Mice, Inbred BALB C; Models, Animal; Vaccination
PubMed: 37126906
DOI: 10.1016/j.biologicals.2023.101678 -
Journal of Comparative Effectiveness... Mar 2017Dengue virus (DENV) is a serious global health problem. CYD-TDC (Dengvaxia) was the first vaccine to gain regulatory approval to try and address this problem. (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Dengue virus (DENV) is a serious global health problem. CYD-TDC (Dengvaxia) was the first vaccine to gain regulatory approval to try and address this problem.
AIM
Summarize all available evidence on the immunogenicity, efficacy and safety of the CYD-TDV dengue vaccine.
METHOD
Meta-analysis and systematic review.
RESULTS
The best and worst immunogenicity results were for DENV4 and DENV1, respectively. Vaccine efficacy of 60% was derived from studies with participants aged 2-16 years old, with DENV4 and DENV2 presenting the best and worst results, respectively. Erythema and swelling were more frequent with CYD-TDV. No differences were detected for systemic adverse events.
CONCLUSION
CYD-TDV showed moderate efficacy in children and adolescents. From the immunogenicity results in adults, we can expect satisfactory efficacy from vaccination in this population.
Topics: Adaptive Immunity; Adolescent; Child; Child, Preschool; Dengue; Dengue Vaccines; Female; Humans; Immunogenicity, Vaccine; Male; Patient Safety; Treatment Outcome
PubMed: 28084784
DOI: 10.2217/cer-2016-0045 -
Frontiers in Immunology 2022Epstein-Barr virus (EBV) is the causal agent of infectious mononucleosis and has been associated with various cancers and autoimmune diseases. Despite decades of...
BACKGROUND
Epstein-Barr virus (EBV) is the causal agent of infectious mononucleosis and has been associated with various cancers and autoimmune diseases. Despite decades of research efforts to combat this major global health burden, there is no approved prophylactic vaccine against EBV. To facilitate the rational design and assessment of an effective vaccine, we systematically reviewed pre-clinical and clinical prophylactic EBV vaccine studies to determine the antigens, delivery platforms, and animal models used in these studies.
METHODS
We searched Cochrane Library, ClinicalTrials.gov, Embase, PubMed, Scopus, Web of Science, WHO's Global Index Medicus, and Google Scholar from inception to June 20, 2020, for EBV prophylactic vaccine studies focused on humoral immunity.
RESULTS
The search yielded 5,614 unique studies. 36 pre-clinical and 4 clinical studies were included in the analysis after screening against the exclusion criteria. In pre-clinical studies, gp350 was the most commonly used immunogen (33 studies), vaccines were most commonly delivered as monomeric proteins (12 studies), and mice were the most used animal model to test immunogenicity (15 studies). According to an adaptation of the CAMARADES checklist, 4 pre-clinical studies were rated as very high, 5 as high, 13 as moderate quality, 11 as poor, and 3 as very poor. In clinical studies, gp350 was the sole vaccine antigen, delivered in a vaccinia platform (1 study) or as a monomeric protein (3 studies). The present study was registered in PROSPERO (CRD42020198440).
CONCLUSIONS
Four major obstacles have prevented the development of an effective prophylactic EBV vaccine: undefined correlates of immune protection, lack of knowledge regarding the ideal EBV antigen(s) for vaccination, lack of an appropriate animal model to test vaccine efficacy, and lack of knowledge regarding the ideal vaccine delivery platform. Our analysis supports a multivalent antigenic approach including two or more of the five main glycoproteins involved in viral entry (gp350, gB, gH/gL, gp42) and a multimeric approach to present these antigens. We anticipate that the application of two underused challenge models, rhesus macaques susceptible to rhesus lymphocryptovirus (an EBV homolog) and common marmosets, will permit the establishment of correlates of immune protection and attainment of more generalizable data.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=198440, identifier PROSPERO I.D. CRD4202019844.
Topics: Animals; Disease Models, Animal; Epstein-Barr Virus Infections; Herpesvirus 4, Human; Infectious Mononucleosis; Macaca mulatta; Mice; Serologic Tests
PubMed: 35493498
DOI: 10.3389/fimmu.2022.867918 -
Boletin Medico Del Hospital Infantil de... 2021The coronavirus disease 2019 (COVID-19) pandemic has posed significant challenges globally. Continuous transmission of the virus is mostly due to insufficient infection...
BACKGROUND
The coronavirus disease 2019 (COVID-19) pandemic has posed significant challenges globally. Continuous transmission of the virus is mostly due to insufficient infection control measures and a lack of vaccines. Therefore, this review aimed to identify and describe possible vaccines for the prevention of COVID-19.
METHODS
A systematic review of the scientific literature was performed through electronic searches of the main databases to identify published reports or studies on vaccines under development against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Websites from international organizations, institutes of health and research, Google, and references from identified studies were also reviewed. Studies examining the mechanisms of infection, immunopathology, and genomics were excluded.
RESULTS
A total of 141 vaccines in development against SARS-CoV-2 were identified. The technologies used include weakened and inactive viruses, viral vectors, nucleic acids, and proteins. So far, 13 vaccines (9.2%) are under clinical evaluation; only the AZD1222 vaccine is under clinical evaluation Phase II-III. Ad5-nCoV and mRNA-1273 vaccines showed to produce neutralizing antibodies and also to be safe.
CONCLUSIONS
Despite efforts invested in developing SARS-CoV-2 vaccines, more research is still required. The vaccine developers, international health organizations, and the decision-makers of health policies must carry out conjunct cooperation to face the different challenges and guarantee the development of an effective vaccine.
Topics: 2019-nCoV Vaccine mRNA-1273; Animals; Antibodies, Neutralizing; COVID-19; COVID-19 Vaccines; ChAdOx1 nCoV-19; Health Policy; Humans; SARS-CoV-2
PubMed: 33662986
DOI: 10.24875/BMHIM.20000217 -
BMJ Global Health Sep 2021Vaccine hesitancy (VH) and the global decline of vaccine coverage are a major global health threat, and novel approaches for increasing vaccine confidence and uptake are...
BACKGROUND
Vaccine hesitancy (VH) and the global decline of vaccine coverage are a major global health threat, and novel approaches for increasing vaccine confidence and uptake are urgently needed. 'Nudging', defined as altering the environmental context in which a decision is made or a certain behaviour is enacted, has shown promising results in several health promotion strategies. We present a comprehensive synthesis of evidence regarding the value and impact of nudges to address VH.
METHODS
We conducted a systematic review to determine if nudging can mitigate VH and improve vaccine uptake. Our search strategy used Medical Subject Headings (MeSH) and non-MeSH terms to identify articles related to nudging and vaccination in nine research databases. 15 177 titles were extracted and assessed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The final list of included articles was evaluated using the Mixed Methods Appraisal Tool and the Grading of Recommendations, Assessment, Development and Evaluations framework.
FINDINGS
Identified interventions are presented according to a framework for behaviour change, MINDSPACE. Articles (n=48) from 10 primarily high-income countries were included in the review. Nudging-based interventions identified include using reminders and recall, changing the way information is framed and delivered to an intended audience, changing the messenger delivering information, invoking social norms and emotional affect (eg, through storytelling, dramatic narratives and graphical presentations), and offering incentives or changing defaults. The most promising evidence exists for nudges that offer incentives to parents and healthcare workers, that make information more salient or that use trusted messengers to deliver information. The effectiveness of nudging interventions and the direction of the effect varies substantially by context. Evidence for some approaches is mixed, highlighting a need for further research, including how successful interventions can be adapted across settings.
CONCLUSION
Nudging-based interventions show potential to increase vaccine confidence and uptake, but further evidence is needed for the development of clear recommendations. The ongoing COVID-19 pandemic increases the urgency of undertaking nudging-focused research.
PROSPERO REGISTRATION NUMBER
CRD42020185817.
Topics: COVID-19; Health Personnel; Humans; Pandemics; SARS-CoV-2; Vaccination
PubMed: 34593513
DOI: 10.1136/bmjgh-2021-006237 -
International Journal of Environmental... Jun 2023Vaccines effectively protect against COVID-19, but vaccine hesitancy and refusal hinder vaccination rates. This systematic review aimed to (1) review and describe... (Review)
Review
Vaccines effectively protect against COVID-19, but vaccine hesitancy and refusal hinder vaccination rates. This systematic review aimed to (1) review and describe current interventions for addressing COVID-19 vaccine hesitancy/refusal and (2) assess whether these interventions are effective for increasing vaccine uptake. The protocol was registered prospectively on PROSPERO and comprehensive search included Medline, Embase, CINAHL, PsycInfo, and Web of Science databases. Only studies that evaluated the effectiveness of non-financial interventions to address COVID-19 vaccine hesitancy were included, while those focusing intentions or financial incentive were excluded. Risk of bias for all included studies was evaluated using Cochrane risk of bias tools. In total, six articles were included in the review (total participants = 200,720). A narrative synthesis was performed due to the absence of common quantitative metrics. Except for one randomized controlled trial, all studies reported that interventions were effective, increasing COVID-19 vaccination rates. However, non-randomized studies were subject to confounding biases. Evidence on the effectiveness of COVID-19 vaccine hesitancy interventions remains limited and further evidence is needed for the development of clear guidance on effective interventions to increase vaccine uptake.
Topics: Humans; COVID-19 Vaccines; COVID-19; Biological Transport; Benchmarking; Databases, Factual; Vaccination
PubMed: 37372669
DOI: 10.3390/ijerph20126082 -
Biomedicine & Pharmacotherapy =... Dec 2021Dengue virus (DENV) is a global health threat causing about half of the worldwide population to be at risk of infection, especially the people living in tropical and...
Dengue virus (DENV) is a global health threat causing about half of the worldwide population to be at risk of infection, especially the people living in tropical and subtropical area. Although the dengue disease caused by dengue virus (DENV) is asymptomatic and self-limiting in most people with first infection, increased severe dengue symptoms may be observed in people with heterotypic secondary DENV infection. Since there is a lack of specific antiviral medication, the development of dengue vaccines is critical in the prevention and control this disease. Several targets and strategies in the development of dengue vaccine have been demonstrated. Currently, Dengvaxia, a live-attenuated chimeric yellow-fever/tetravalent dengue vaccine (CYD-TDV) developed by Sanofi Pasteur, has been licensed and approved for clinical use in some countries. However, this vaccine has demonstrated low efficacy in children and dengue-naïve individuals and also increases the risk of severe dengue in young vaccinated recipients. Accordingly, many novel strategies for the dengue vaccine are under investigation and development. Here, we conducted a systemic literature review according to PRISMA guidelines to give a concise overview of various aspects of the vaccine development process against DENVs, mainly targeting five potential strategies including live attenuated vaccine, inactivated virus vaccine, recombinant subunit vaccine, viral-vector vaccine, and DNA vaccine. This study offers the comprehensive view of updated information and current progression of immunogen selection as well as strategies of vaccine development against DENVs.
Topics: Animals; Dengue; Dengue Vaccines; Dengue Virus; Humans; Treatment Outcome; Vaccine Development; Vaccine Efficacy; Vaccines, Attenuated; Vaccines, DNA; Vaccines, Inactivated; Vaccines, Synthetic; Viral Envelope Proteins; Viral Nonstructural Proteins
PubMed: 34634560
DOI: 10.1016/j.biopha.2021.112304 -
The Lancet. Microbe Feb 2024The high strain diversity of Streptococcus pyogenes serves as a major obstacle to vaccine development against this leading global pathogen. We did a systematic review of... (Review)
Review
The high strain diversity of Streptococcus pyogenes serves as a major obstacle to vaccine development against this leading global pathogen. We did a systematic review of studies in PubMed, MEDLINE, and Embase that reported the global distribution of S pyogenes emm-types and emm-clusters from Jan 1, 1990, to Feb 23, 2023. 212 datasets were included from 55 countries, encompassing 74 468 bacterial isolates belonging to 211 emm-types. Globally, an inverse correlation was observed between strain diversity and the UNDP Human Development Index (HDI; r=-0·72; p<0·0001), which remained consistent upon subanalysis by global region and site of infection. Greater strain diversity was associated with a lower HDI, suggesting the role of social determinants in diseases caused by S pyogenes. We used a population-weighted analysis to adjust for the disproportionate number of epidemiological studies from high-income countries and identified 15 key representative isolates as vaccine targets. Strong strain type associations were observed between the site of infection (invasive, skin, and throat) and several streptococcal lineages. In conclusion, the development of a truly global vaccine to reduce the immense burden of diseases caused by S pyogenes should consider the multidimensional diversity of the pathogen, including its social and environmental context, and not merely its geographical distribution.
Topics: Humans; Streptococcus pyogenes; Streptococcal Infections; Antigens, Bacterial; Bacterial Outer Membrane Proteins; Vaccines
PubMed: 38070538
DOI: 10.1016/S2666-5247(23)00318-X -
Journal of Education and Health... 2022Vaccine hesitancy leads to an increase in morbidity, mortality, and health-care burden. Reasons for vaccine hesitancy include anti-vax group statements, misinformation... (Review)
Review
BACKGROUND
Vaccine hesitancy leads to an increase in morbidity, mortality, and health-care burden. Reasons for vaccine hesitancy include anti-vax group statements, misinformation about vaccine side effects, speed of vaccine development, and general disbelief in the existence of viruses like COVID-19. Medical students are future physicians and are key influencers in the uptake of vaccines. Hence, investigating vaccine hesitancy in this population can help to overcome any barrier in vaccine acceptance.
METHODS
In this paper, we review five articles on COVID-19 vaccine hesitancy in medical students and consider potential future research. All published papers relevant to the topic were obtained through extensive search using major databases. Inclusion criteria included studies that specifically investigated COVID-19 vaccine hesitancy in medical students published between 2020 and 2021. Exclusion criteria included studies that investigated vaccine hesitancy in health-care professionals, allied health, and viruses apart from COVID-19. A total of 10 studies were found from our search.
RESULTS
Based on our exclusion criteria, only five studies were included in our review. The sample size ranged from 168 to 2133 medical students. The percentage of vaccine hesitancy in medical students ranged from 10.6 to 65.1%. Reasons for vaccine hesitancy included concern about serious side effects, vaccine efficacy, misinformation and insufficient information, disbelief in public health experts, financial costs, and belief that they had acquired immunity.
CONCLUSION
These results suggest that vaccine hesitancy is an important cause of the incidence and prevalence of COVID-19 cases. Identifying the barriers of vaccine hesitancy in prospective physicians can help increase vaccination uptake in the general public. Further research is necessary to identify the root cause of these barriers.
PubMed: 36177403
DOI: 10.4103/jehp.jehp_940_21 -
Frontiers in Public Health 2023The purpose of this systematic review was to report on the vaccine efficacy (VE) of three SARS-CoV-2 vaccines approved by Health Canada: Pfizer BioNTech, Moderna, and...
The purpose of this systematic review was to report on the vaccine efficacy (VE) of three SARS-CoV-2 vaccines approved by Health Canada: Pfizer BioNTech, Moderna, and AstraZeneca. Four databases were searched for primary publications on population-level VE. Ninety-two publications matched the inclusion criteria, and the extracted data were separated by vaccine type: mRNA vaccines (Pfizer and Moderna) and the AstraZeneca vaccine. The median VE for PCR-positive patients and various levels of clinical disease was determined for the first and second doses of both vaccine types against multiple SARS-CoV-2 variants. The median VE for PCR-positive infections against unidentified variants from an mRNA vaccine was 64.5 and 89%, respectively, after one or two doses. The median VE for PCR-positive infections against unidentified variants from the AstraZeneca vaccine was 53.4 and 69.6%, respectively, after one or two doses. The median VE for two doses of mRNA for asymptomatic, symptomatic, and severe infection against unidentified variants was 85.5, 93.2, and 92.2%, respectively. The median VE for two doses of AstraZeneca for asymptomatic, symptomatic, and severe infection against unidentified variants was 69.7, 71, and 90.2%, respectively. Vaccine efficacy numerically increased from the first to the second dose, increased from the first 2 weeks to the second 2 weeks post-vaccination for both doses, but decreased after 4 months from the second dose. Vaccine efficacy did not differ by person's age.
Topics: Humans; COVID-19 Vaccines; SARS-CoV-2; Vaccine Efficacy; COVID-19; Vaccines
PubMed: 37942238
DOI: 10.3389/fpubh.2023.1229716