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Molecular Biotechnology Jul 2023Emerging infectious diseases have vigorously devastated the global economy and health sector; cost-effective plant-based vaccines (PBV) can be the potential solution to... (Review)
Review
Emerging infectious diseases have vigorously devastated the global economy and health sector; cost-effective plant-based vaccines (PBV) can be the potential solution to withstand the current health economic crisis. The prominent role of tobacco as an efficient expression system for PBV has been well-established for decades, through this review we highlight the importance of tobacco-based vaccines (TBV) against evolving infectious diseases in humans. Studies focusing on the use of TBV for human infectious diseases were searched in PubMed, Google Scholar, and science direct from 1995 to 2021 using the keywords Tobacco-based vaccines OR transgenic tobacco OR Nicotiana benthamiana vaccines AND Infectious diseases or communicable diseases. We carried out a critical review of the articles and studies that fulfilled the eligibility criteria and were included in this review. Of 976 studies identified, only 63 studies fulfilling the eligibility criteria were included, which focused on either the in vitro, in vivo, or clinical studies on TBV for human infectious diseases. Around 43 in vitro studies of 23 different infectious pathogens expressed in tobacco-based systems were identified and 23 in vivo analysis studies were recognized to check the immunogenicity of vaccine candidates while only 10 of these were subjected to clinical trials. Viral infectious pathogens were studied more than bacterial pathogens. From our review, it was evident that TBV can be an effective health strategy to combat the emerging viral infectious diseases which are very difficult to manage with the current health facilities. The timely administration of cost-effective TBV can prevent the outburst of viral infections, thereby can protect the global healthcare system to a greater extent.
Topics: Humans; Nicotiana; Vaccines; Vaccines, Virus-Like Particle; Malaria Vaccines; Virus Diseases
PubMed: 36528727
DOI: 10.1007/s12033-022-00627-5 -
BMC Medicine Sep 2014Identifying Plasmodium vivax antigen-specific antibodies associated with P. vivax infection and protective immunity is key to the development of serosurveillance tools... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Identifying Plasmodium vivax antigen-specific antibodies associated with P. vivax infection and protective immunity is key to the development of serosurveillance tools and vaccines for malaria. Antibody targets of P. vivax can be identified by seroepidemiological studies of individuals living in P. vivax-endemic areas, and is an important strategy given the limited ability to culture P. vivax in vitro. There have been numerous studies investigating the association between P. vivax antibody responses and P. vivax infection, but there has been no standardization of results to enable comparisons across populations.
METHODS
We performed a systematic review with meta-analysis of population-based, cross-sectional, case-control, and cohort studies of individuals living in P. vivax-endemic areas. We searched 6 databases and identified 18 studies that met predefined inclusion and quality criteria, and examined the association between antibody responses to P. vivax antigens and P. vivax malaria.
RESULTS
The majority of studies were published in South America (all from Brazil) and the rest from geographically diverse areas in the Asia-Pacific region. Considerable heterogeneity in estimates was observed, but IgG responses to PvCSP, PvMSP-119, PvMSP-9RIRII, and PvAMA1 were associated with increased odds of P. vivax infection in geographically diverse populations. Potential sources of heterogeneity included study design, different transmission intensities and transmigrant populations. Protective associations were observed for antibodies to PvMSP-119, PvMSP-1NT, PvMSP-3α and PvMSP-9NT antigens, but only in single geographical locations.
CONCLUSIONS
This systematic review revealed several antigen-specific antibodies that were associated with active infection and protective immunity, which may be useful biomarkers. However, more studies are needed on additional antigens, particularly cohort studies to increase the body of evidence for protective immunity. More studies representing diverse geographical regions encompassing varying P. vivax endemicities are needed to validate the generalizability of the findings and to provide a solid evidence base for the use of P. vivax antigens in vaccines and serosurveillance tools.
Topics: Antibodies, Protozoan; Antigens, Protozoan; Biomarkers; Female; Humans; Malaria, Vivax; Male; Plasmodium vivax; Protozoan Proteins; Seroepidemiologic Studies
PubMed: 25199532
DOI: 10.1186/s12916-014-0150-1 -
Comparative Immunology, Microbiology... Aug 2018Toxoplasma gondii is an obligate intracellular parasitic protozoan that infects a wide variety of vertebrates as intermediate hosts. The aim of the current systematic... (Review)
Review
Toxoplasma gondii is an obligate intracellular parasitic protozoan that infects a wide variety of vertebrates as intermediate hosts. The aim of the current systematic review study is to clarify the latest status of studies in the literature regarding rhoptry-associated recombinant proteins or rhoptry-associated recombinant DNAs as potential vaccines against toxoplasmosis. The search was performed systematically in 8 databases, four in English and four in Persian, up to February 2017. Overall, ROP2 was the most commonly used ROPs in DNA vaccines (27.27%) and protein vaccines (6.81%). Furthermore, regarding the type of adjuvants, route and dose of vaccination, animal models, challenge methods, and measurement of immune responses has been discussed in the text. It is hoped that this article help researchers to conduct more effective studies in the field of immunization against T. gondii.
Topics: Animals; Antibodies, Protozoan; Antigens, Protozoan; Humans; Immunization; Protozoan Proteins; Protozoan Vaccines; Recombinant Proteins; Toxoplasma; Toxoplasmosis, Animal; Vaccination; Vaccines, DNA
PubMed: 30290885
DOI: 10.1016/j.cimid.2018.09.005 -
PloS One 2022Malaria is the second leading cause of death in children after diarrheal disease, with low- and middle-income countries (LMICs) accounting for over 9 in 10 incidence and... (Meta-Analysis)
Meta-Analysis
A systematic review and meta-analysis of the prevalence of caregiver acceptance of malaria vaccine for under-five children in low-income and middle-income countries (LMICs).
INTRODUCTION
Malaria is the second leading cause of death in children after diarrheal disease, with low- and middle-income countries (LMICs) accounting for over 9 in 10 incidence and deaths. Widespread acceptance and uptake of the RTS,S vaccine, recently approved by the world health organization (WHO), is projected to significantly reduce malaria incidence and deaths. Therefore, we conducted this systematic review and meta-analysis with the aim to determine the malaria vaccine acceptance rate and the factors associated with acceptance.
METHODS
We searched six databases including Google Scholar, PubMed, Cochrane, African Index Medicus, The Regional Office for Africa Library, and WHO Institutional Repository for Information Sharing (IRIS) to identify studies evaluating the malaria vaccine acceptance rate. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. Studies were included if they were original articles published in the English language in peer-reviewed journals and assessed the prevalence of willingness to accept a free malaria vaccine, and not qualitative. The risk of publication bias was checked using both Beggar's funnel plot and Egger's test, while the I2 statistic was used to assess the heterogeneity of the included studies. Study quality was determined using the Newcastle-Ottawa scale. A meta-analysis was performed using a random effects model to evaluate the pooled prevalence of malaria vaccine acceptance. The protocol for this article was registered prospectively on the International Prospective Register for Systematic Reviews (PROSPERO), with ID number CRD42022334282).
RESULTS
Our analysis included 11 studies with a total sample size of 14, 666 participants. The aggregate malaria vaccine acceptance rate was 95.3% (95% CI:93.0%-97.2%). Among the general population, the acceptance rate was 96.3% (95% CI:92.0%-99.0%) and among mothers, it was 94.4% (95% CI:90.8%-97.2%). By country, Nigeria had the highest acceptance rate (97.6%, 95% CI:96.0%-98.8%), followed by Ghana (94.6%, 95% CI:93.8%-95.3%) and Tanzania (92.5%, 95% CI:84.4%-97.8%). Sociodemographic determinants of vaccine acceptance included place of residence, tribe, age, sex, occupation, and religion. Reasons for low acceptance included safety concerns, efficacy profile, vaccine's requirement for multiple injections, and poor level of awareness.
CONCLUSION
Future efforts should be focused on identifying factors that may improve the actual uptake of the RTS,S vaccine in malaria-endemic communities.
Topics: Child; Humans; Malaria Vaccines; Prevalence; Caregivers; Developing Countries; Ghana
PubMed: 36455209
DOI: 10.1371/journal.pone.0278224 -
Vaccine Oct 2020Leishmania (L.) infantum is a vector-borne parasite currently endemic in several Southern countries of European Union (EU), and dogs represent the main reservoir and... (Meta-Analysis)
Meta-Analysis Review
Leishmania (L.) infantum is a vector-borne parasite currently endemic in several Southern countries of European Union (EU), and dogs represent the main reservoir and hosts. Data from clinical trials are inconsistent with respect to the efficacy of vaccination against L. infantum infection. Therefore, a quantitative synthesis via pairwise meta-analysis was performed in agreement with the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) to increase the strength of evidence and assess the real efficacy profile of vaccines against L. infantum currently approved in EU. Data obtained from 1,394 dogs were extracted from 10 studies. The overall analysis indicated that vaccination is significantly effective in protecting against L. infantum infection (RR 0.40, 95%CI 0.23-0.72; I 70%; P < 0.01 vs. negative controls). The subset analysis performed by excluding the effect modifiers and by considering only the studies that assessed the efficacy of vaccines currently available in EU, indicated that CaniLeish® (RR 0.38, 95%CI 0.20-0.72; I 0%), but not Letifend® (RR 0.43, 95%CI 0.15-1.22; I 37%), significantly protected against L. infantum infection when compared to negative controls (P < 0.05). The number needed to treat analysis showed that 3.77 (95%CI 2.59-6.94) and 10.99 (95%CI 8.28-16.34) dogs had to be treated with CaniLeish® and Letifend®, respectively, to prevent one case of infection compared to negative controls. Vaccination is effective in protecting against the risk L. infantum infection, but further studies are needed to assess whether CaniLeish® and Letifend® are characterized by similar efficacy profile.
Topics: Animals; Antibodies, Protozoan; Dog Diseases; Dogs; European Union; Leishmania infantum; Leishmaniasis, Visceral; Vaccines
PubMed: 32883556
DOI: 10.1016/j.vaccine.2020.08.051 -
BMC Infectious Diseases Dec 2021The development of novel malaria vaccines and antimalarial drugs is limited partly by emerging challenges to conduct field trials in malaria endemic areas, including...
BACKGROUND
The development of novel malaria vaccines and antimalarial drugs is limited partly by emerging challenges to conduct field trials in malaria endemic areas, including unknown effects of existing immunity and a reported fall in malaria incidence. As a result, Controlled Human Malaria Infection (CHMI) has become an important approach for accelerated development of malarial vaccines and drugs. We conducted a systematic review of the literature to establish aggregate evidence on the reproducibility of a malaria sporozoite challenge model.
METHODS
A systematic review of research articles published between 1990 and 2018 on efficacy testing of malaria vaccines and drugs using sporozoite challenge and sporozoite infectivity studies was conducted using Pubmed, Scopus, Embase and Cochrane Library, ClinicalTrials.gov and Trialtrove. The inclusion criteria were randomized and non-randomized, controlled or open-label trials using P. falciparum or P. vivax sporozoite challenges. The data were extracted from articles using standardized data extraction forms and descriptive analysis was performed for evidence synthesis. The endpoints considered were infectivity, prepatent period, parasitemia and safety of sporozoite challenge.
RESULTS
Seventy CHMI trials conducted with a total of 2329 adult healthy volunteers were used for analysis. CHMI was induced by bites of mosquitoes infected with P. falciparum or P. vivax in 52 trials and by direct venous inoculation of P. falciparum sporozoites (PfSPZ challenge) in 18 trials. Inoculation with P. falciparum-infected mosquitoes produced 100% infectivity in 40 studies and the mean/median prepatent period assessed by thick blood smear (TBS) microscopy was ≤ 12 days in 24 studies. On the other hand, out of 12 infectivity studies conducted using PfSPZ challenge, 100% infection rate was reproduced in 9 studies with a mean or median prepatent period of 11 to 15.3 days as assessed by TBS and 6.8 to 12.6 days by PCR. The safety profile of P. falciparum and P.vivax CHMI was characterized by consistent features of malaria infection.
CONCLUSION
There is ample evidence on consistency of P. falciparum CHMI models in terms of infectivity and safety endpoints, which supports applicability of CHMI in vaccine and drug development. PfSPZ challenge appears more feasible for African trials based on current evidence of safety and efficacy.
Topics: Adult; Animals; Humans; Malaria Vaccines; Malaria, Falciparum; Pharmaceutical Preparations; Reproducibility of Results; Sporozoites
PubMed: 34930178
DOI: 10.1186/s12879-021-06953-4 -
Vaccine Nov 2016Shifting the malaria priorities from a paradigm of control and elimination to a goal of global eradication calls for renewed attention to the interruption of malaria... (Review)
Review
Shifting the malaria priorities from a paradigm of control and elimination to a goal of global eradication calls for renewed attention to the interruption of malaria transmission. Sustained progress toward eradication will require both improved understanding of infectious reservoirs and efficient development of novel transmission-blocking interventions, such as rapidly acting and highly efficacious therapeutics and vaccines. Here, we review the direct skin feeding assay (DSF), which has been proposed as a valuable tool for measuring the in natura transmission of malaria parasites from human hosts to mosquito vectors across heterogeneous populations. To capture the methodological breadth of this assay's use, we first systematically review and qualitatively synthesize previously published investigations using DSFs to study malaria transmission in humans. Then, using a recent Phase 1 trial in Mali of the Pfs25H-EPA/Alhydrogel® vaccine candidate (NCT01867463) designed to interrupt Plasmodium falciparum transmission as a case study, we describe the potential opportunities and current limitations of utilizing the endpoints measured by DSF in making early clinical decisions for individually randomized transmission-interrupting intervention candidates. Using simulations based on the data collected in the clinical trial, we demonstrate that the capacity of the DSF to serve as an evaluative tool is limited by the statistical power constraints of the "effective sample size" (i.e. the number of subjects that are capable of transmitting at the time of feeding). Altogether, our findings suggest DSFs have great potential utility for assessing the public health impacts of emerging antimalarial tools, but additional research is needed to address issues of scalability and to establish correlation with community-wide clinical endpoints as well as complementary in vitro measures, such as standard membrane feeding assays.
Topics: Adult; Animals; Anopheles; Clinical Trials as Topic; Feeding Behavior; Female; Humans; Malaria Vaccines; Malaria, Falciparum; Male; Middle Aged; Mosquito Vectors; Protozoan Proteins; Skin; Young Adult
PubMed: 27789147
DOI: 10.1016/j.vaccine.2016.10.027 -
Revista Da Sociedade Brasileira de... 2020Trypanosoma rangeli is a protozoan that infects several domestic and wild mammals and shows significant distribution in Latin American countries. T. rangeli infection is... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Trypanosoma rangeli is a protozoan that infects several domestic and wild mammals and shows significant distribution in Latin American countries. T. rangeli infection is similar to Chagas disease, both in diagnostic and prophylactic terms. Thus, the objective of this work was to review the diagnostic aspects and use of T. rangeli as an immunogen for Trypanosoma cruzi infection.
METHODS
For this elaboration, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were adopted with descriptors derived from the Medical Subject Headings (MeSH) platform in the PubMed/MEDLINE and SciELO databases. The inclusion criteria were defined as original articles on "Trypanosoma rangeli" and diagnostic aspects of T. rangeli infection in humans and/or research on the possible vaccines developed using T. rangeli strains for T. cruzi infection.
RESULTS
After applying the inclusion and exclusion criteria, 18 articles were procured, of which 4 addressed research on the possible vaccines developed using T. rangeli for T. cruzi infection in vertebrates and the remaining 14 predominantly dealt with the diagnostic aspects of T. rangeli infection in humans.
CONCLUSIONS
In this study, we formulated a compilation of the essential literature on this subject, emphasizing the need for more accurate and accessible techniques for the differential diagnosis of infections caused by both protozoa, and underscored several prospects in the search for a vaccine for Chagas disease.
Topics: Animals; Humans; Trypanosoma; Trypanosoma cruzi; Trypanosoma rangeli
PubMed: 32935777
DOI: 10.1590/0037-8682-0608-2019 -
Future Microbiology 2015The first clinical Phase III trial evaluating a malaria vaccine was completed in December 2013 at 11 sites from seven sub-Saharan African countries. This systematic... (Review)
Review
The first clinical Phase III trial evaluating a malaria vaccine was completed in December 2013 at 11 sites from seven sub-Saharan African countries. This systematic review assesses data of Phase I-III trials including malaria-naive adults and adults, children and infants from malaria endemic settings in sub-Saharan Africa. The main endpoint of this systematic review was an analysis of the consistency of efficacy and immunogenicity data from respective Phase I-III trials. In addition, safety data from a pooled analysis of RTS/AS Phase II trials and RTS,S/AS01 Phase III trial were reviewed. The RTS,S/AS01 malaria vaccine may become available on the market in the coming year. If so, further strategies should address challenges on how to optimize vaccine efficacy and implementation of RTS,S/AS01 vaccine within the framework of established malaria control measures.
Topics: Adult; Africa South of the Sahara; Child; Child, Preschool; Humans; Infant; Malaria Vaccines; Malaria, Falciparum; Plasmodium falciparum; Vaccination
PubMed: 26437872
DOI: 10.2217/fmb.15.90 -
Preventive Veterinary Medicine Nov 2014Canine leishmaniosis (CanL) is an important zoonotic disease; however, the efficacy of available vaccines for the prevention of naturally-occurring Leishmania infantum... (Review)
Review
Canine leishmaniosis (CanL) is an important zoonotic disease; however, the efficacy of available vaccines for the prevention of naturally-occurring Leishmania infantum (L. infantum) infection in dogs remains unclear. The objective of this review was to determine the efficacy of currently available vaccines to prevent naturally-occurring L. infantum infection in dogs. Four bibliographic databases (CAB Direct 2011, Web of Science 2011, U.S. National Library of Medicine 2011 and Literatura Latino Americana e do Caribe em Ciências da Saúde) were searched along with eight sets of conference proceedings and the International Veterinary Information Service (IVIS) database, from 1980 to November 2012. Randomised controlled trials (RCTs), non-randomised clinical trials (NRCTs), cohort studies and case-control studies that investigated vaccine efficacy for natural L. infantum infection in dogs were eligible for inclusion. Two review authors independently assessed each study against the inclusion criteria, independently extracted relevant data from all included studies and assessed the risk of methodological shortcomings in each individual study. The odds ratio (OR) and absolute risk reduction (ARR) for dichotomous outcomes and mean difference for continuous outcomes were calculated. Meta-analysis was not performed due to heterogeneity of the studies identified. The search was conducted for all mitigations for CanL and yielded the title and abstract of 937 articles, from which 84 articles were screened based on full text. Twelve studies on vaccinations (five RCTs, seven NRCTs) were identified. Ten studies were at a high risk of methodological shortcomings, whilst two were at an unclear risk. The use of 200 μg ALM protein, Leishmune(®), CaniLeish(®), LiESAp with MDP, and ALM with BCG tended to significantly reduce the proportion of dogs infected with L. infantum based on either parasitological or serological evidence. The use of lyophilized protein vaccine significantly increased the proportion of dogs infected with L. infantum based on either parasitological or serological evidence. There is peer-reviewed evidence that control measures are effective in preventing CanL with the results suggesting that between 6 and 54% of infections could be prevented with vaccination. However, this evidence is based on a small number of RCTs, all of which are either at high or unclear risk of methodological shortcomings. Well-designed, adequately powered and properly reported randomised clinical trials are needed to clearly establish efficacy of vaccines as CanL control measures.
Topics: Animals; Dog Diseases; Dogs; Leishmaniasis; Leishmaniasis Vaccines
PubMed: 25074635
DOI: 10.1016/j.prevetmed.2014.06.015