Evaluation Of Vaccine Efficacy Research Articles

Development of an automatic tubular chemiluminescence immunoassay using magnetic particles for the detection of antibodies against foot-and-mouth disease virus serotype A.

Foot-and-mouth disease virus (FMDV) causes significant financial losses in animal farms worldwide. Specific antibody monitoring of FMDV post-vaccination is important for evaluating vaccine efficacy, as well as the prevention and control of foot-and-mouth disease (FMD). In this study, we developed a fully automatic tubular chemiluminescence immunoassay method based on magnetic particles (A-MPCLIA) to specifically detect antibodies against FMDV serotype A. The diagnostic sensitivity (Dsn) and diagnostic specificity (Dsp) of A-MPCLIA were determined to be 96.05% and 99%, respectively, with a cut-off value of 30 activity units (U) by detecting the known background swine, cattle, and sheep serum. The developed method presented good Dsn, Dsp, and repeatability (CV < 10%). The activity units of A-MPCLIA, determined using 23 animals vaccinated with FMDV serotypes O, A, and Asia 1 univalent inactivated vaccine and nine serum samples from naïve animals, were significantly positively correlated with the titers of liquid-phase-blocking enzyme-linked immunosorbent assay (R2 = 0.992) and the titer of the virus neutralization test (R2 = 0.9577). In addition, A-MPCLIA requires less than 20 min, and it is fully automatic in detection. These results showed that A-MPCLIA is a suitable method for the detection of antibodies against FMDV serotype A in the future.

Development of a pan-genotypic monoclonal antibody-based competitive ELISA for the detection of antibodies against Bovine viral diarrhea virus.

Bovine viral diarrhea virus (BVDV), a positive-sense single-stranded RNA virus, causes significant economic losses in the cattle industry. Current diagnostic methods for BVDV exhibit variable sensitivity and specificity, underscoring the need for more rapid and accurate detection approaches. Here, we developed a novel competitive ELISA (cELISA) to detect antibodies against the BVDV E2 protein. We generated three monoclonal antibodies (mAbs)-3E6, 2D5, and 5B9-by immunizing mice with purified BVDV E2 protein expressed in Expi293F cells. Among these, mAb 3E6 displayed superior competitive binding abilities to the E2 protein, enabling effective differentiation between BVDV positive and negative sera. Remarkably, mAb 3E6 exhibited pan-genotypic recognition of various BVDV strains, including BVDV-1a, -1b, -1c, -1m, -1p, -1v, and -2a, while showing no cross-reactivity with the classical swine fever virus (CSFV). Computational modeling using AlphaFold 3 identified domain B of the E2 protein as the primary binding site for mAb 3E6. Building upon these findings, we established a cELISA employing mAb 3E6 and recombinant E2 protein. Receiver-operating characteristic (ROC) analysis revealed outstanding diagnostic performance, achieving a sensitivity of 99.26% and specificity of 98.99%. Further tests confirmed the cELISA's specificity for detecting BVDV-specific antibodies, with no cross-reactivity with antisera from animals infected or immunized against BCoV, BHV-1, BRV, AKAV, LSDV, BLV, and CSFV. Consistency was observed between results from the BVDV E2 cELISA and traditional virus neutralization test (VNT), demonstrating high sensitivity for monitoring antibody dynamics. In performance evaluations, the established cELISA exhibited high concordance with VNT in assessing 160 vaccinated sera and 190 clinical samples. The BVDV E2 cELISA, utilizing mAb 3E6 to target domain B of the BVDV E2 protein, represents a reliable and effective serological diagnostic tool for the detection of antibodies against both BVDV-1 and BVDV-2. This methodology holds significant promise for applications in clinical diagnosis and the evaluation of vaccine efficacy.

Improving precision of vaccine efficacy evaluation using immune correlate data in time-to-event models

Understanding potential differences in vaccine-induced protection between demographic subgroups is key for vaccine development. Vaccine efficacy evaluation across these subgroups in phase 2b or 3 clinical trials presents challenges due to lack of precision: such trials are typically designed to demonstrate overall efficacy rather than to differentiate its value between subgroups. This study proposes a method for estimating vaccine efficacy using immunogenicity (instead of vaccination status) as a predictor in time-to-event models. The method is applied to two datasets from immunogenicity sub-studies of vaccine phase 3 clinical trials for zoster and dengue vaccines. Results show that using immunogenicity-based estimation of efficacy in subgroups using time-to-event models is more precise than the standard estimation. Incorporating immune correlate data in time-to-event models improves precision in estimating efficacy (i.e., yields narrower confidence intervals), which can assist vaccine developers and public health authorities in making informed decisions.

Genomic characteristics, disease outcome and heterologous vaccine effectiveness among cases with SARS CoV-2 infection

BackgroundIn the pursuit of global health security, continuous monitoring of vaccine effectiveness across various viral strains emerges as a crucial imperative. The emergence of SARS-CoV-2 major variants of concern (VOCs), including Alpha, Beta, Delta, and Omicron, has added complexity to the COVID-19 vaccination landscape.ObjectivesTo assess illness severity, evaluate vaccine efficacy across varying doses and types, and determine effectiveness against major VOCs within the population.MethodsThis retrospective cohort study, conducted in Abu Dhabi, United Arab Emirates, focuses on a cohort of 44,073 SARS-CoV-2 positive cases from February 2021 to May 2022, dominated by the Delta and Omicron variants. The study employed a nested case-control design, analyzing hospital admissions for confirmed SARS-CoV-2 infection.ResultsVaccine effectiveness was higher among heterologus-boosted individuals at 87% (95% CI:79%-93%) compared to homologus-boosted individuals at 59% (95% CI: 48%-68%) and fully vaccinated, non-boosted adults at 53% (95% CI: 46%-59%). These findings highlight the importance of heterologous boosting, particularly against rapidly evolving viral variants, offering valuable insights for refining pandemic response strategies.ConclusionThe study underscores the critical need for ongoing assessment and adaptation of vaccination strategies to the evolving viral landscape.

Development of KSHV vaccine platforms and chimeric MHV68-K-K8.1 glycoprotein for evaluating the in vivo immunogenicity and efficacy of KSHV vaccine candidates.

Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 is an etiological agent of Kaposi's Sarcoma, multicentric Castleman's disease, and primary effusion lymphoma. Considering the high seroprevalence reaching up to 80% in sub-Saharan Africa, an effective vaccine is crucial for preventing KSHV infection. However, vaccine development has been limited due to the lack of an effective animal model that supports KSHV infection. Murine Herpesvirus 68 (MHV68), a natural mouse pathogen persisting lifelong post-infection, presents a promising model for KSHV infection. In this study, we developed KSHV vaccine and a chimeric MHV68 carrying the KSHV glycoprotein, serving as a surrogate challenge virus for testing KSHV vaccines in a mouse model. Among KSHV virion glycoproteins, K8.1 is the most abundant envelope glycoprotein with the highest immunogenicity. We developed two K8.1 vaccines: K8.1 mRNA-lipid nanoparticle (LNP) vaccine and K8.126-87-Ferritin (FT) nanoparticle vaccines. Both induced humoral responses in immunized mice, whereas K8.1 mRNA LNP also induced T cell responses. Using BACmid-mediated homologous recombination, the MHV68 M7 (gp150) gene was replaced with KSHV K8.1 gene to generate chimeric MHV68-K-K8.1. MHV68-K-K8.1 established acute and latent infection in the lungs and spleens of infected mice, respectively. Mice immunized with K8.1 mRNA LNP or K8.126-87-FT showed a reduction of MHV68-K-K8.1 titer but not MHV68 wild type (WT) titer in the lung. In addition, viral reactivation of MHV68-K-K8.1 was also significantly reduced in K8.1 mRNA LNP-immunized mice. This study demonstrates the effectiveness of two vaccine candidates in providing immunity against KSHV K8.1 and introduces a surrogate MHV68 system for evaluating vaccine efficacy in vivo.IMPORTANCEKaposi's sarcoma-associated herpesvirus (KSHV) is a prevalent virus that establishes lifelong persistent infection in humans and is linked to several malignancies. While antiretroviral therapy has reduced Kaposi's Sarcoma (KS) complications in people with HIV, KS still affects individuals with well-controlled HIV, older men without HIV, and transplant recipients. Despite its significant impact on human health, however, research on KSHV vaccine has been limited, mainly due to the lack of interest and the absence of a suitable animal model. This study addresses these challenges by developing KSHV K8.1 vaccine with two platforms, mRNA lipid nanoparticle (LNP) and FT nanoparticle. Additionally, chimeric virus, MHV68-K-K8.1, was created to evaluate KSHV vaccine efficacy in vivo. Vaccination of K8.1 mRNA LNP or K8.126-87-FT significantly reduced MHV68-K-K8.1 titers. Developing an effective KSHV vaccine requires an innovative approach to ensure safety and efficacy, especially for the immunocompromised population and people with limited healthcare resources. This study could be a potential blueprint for future KSHV vaccine development.

ELISA-R: an R-based method for robust ELISA data analysis.

Enzyme-linked immunosorbent assay (ELISA) is a technique to detect the presence of an antigen or antibody in a sample. ELISA is a simple and cost-effective method that has been used for evaluating vaccine efficacy by detecting the presence of antibodies against viral/bacterial antigens and diagnosis of disease stages. Traditional ELISA data analysis utilizes a standard curve of known analyte, and the concentration of the unknown sample is determined by comparing its observed optical density against the standard curve. However, in the case of vaccine research for complicated bacteria such as Mycobacterium tuberculosis (Mtb), there is no prior information regarding the antigen against which high-affinity antibodies are generated and therefore plotting a standard curve is not feasible. Consequently, the analysis of ELISA data in this instance is based on a comparison between vaccinated and unvaccinated groups. However, to the best of our knowledge, no robust data analysis method exists for "non-standard curve" ELISA. In this paper, we provide a straightforward R-based ELISA data analysis method with open access that incorporates end-point titer determination and curve-fitting models. Our modified method allows for direct measurement data input from the instrument, cleaning and arranging the dataset in the required format, and preparing the final report with calculations while leaving the raw data file unchanged. As an illustration of our method, we provide an example from our published data in which we successfully used our method to compare anti-Mtb antibodies in vaccinated vs non-vaccinated mice.

A large epidemiological study on human papillomavirus vaccine post-vaccination symptoms and healthy vaccinee bias

Objective This study aimed to examine the existence of healthy vaccinee bias, a source of distortion in the evaluation of vaccine efficacy, through analysis without random assignment using real data on post-vaccination symptoms from the Nagoya Study, a large epidemiological study of human papillomavirus (HPV) vaccine post-vaccination symptoms.Methods For three school years of individuals born in 1997, 1998, and 1999, as the HPV vaccine had a 2-year target period, 3,246 were first vaccinated at age 14 years and 3,961 were unvaccinated. The proportion of symptom onset in these 7,207 individuals during the unvaccinated period at age 13 years was compared by birth year to examine the presence of a healthy vaccinee bias.Results Only four symptoms were significantly higher among unvaccinated participants, such as the proportion of "severe headache," which occurred in 2010 among those born in 1997, "hyperventilation," which occurred in 2011 among those born in 1998, "fatigue" and "sudden vision loss," which occurred in 2012 among those born in 1999. Healthy vaccinee biases are rarely observed.Conclusion Underestimation of the odds ratio of HPV vaccination due to healthy vaccinee bias is limited, and the claim that the supposedly high odds ratio in the Nagoya Study was masked by a healthy vaccinee bias is invalid.

Immunisation of koalas against Chlamydia pecorum results in significant protection against chlamydial disease and mortality

In 2022, the Australian Government listed the koala as endangered in several states due to habitat destruction, traffic strikes, dog attacks, and Chlamydia pecorum disease. This study evaluates a 10-year assessment of a Major Outer Membrane Protein-based vaccine’s effectiveness against chlamydial disease in wild koalas from Southeast Queensland. Over a decade, 680 koalas were tracked, with five vaccine trials involving 165 koalas. While prior studies only offered up to two years of data, this study’s extended period allowed a thorough evaluation of vaccine efficacy. Results showed that vaccinated koalas had significantly lower disease incidence, with a 64% reduction in chlamydial mortality. This vaccine demonstrated positive impacts on both male and female koalas, highlighting its crucial role in conserving the Australian koala population and mitigating the threats they face.

A non-targeted metabolomics comparative study on plasma of pfizer and sinopharm COVID-19 vaccinated individuals, assessed by (TIMS-QTOF) mass spectrometry

COVID-19 is a highly contagious infectious disease that has posed a global threat, leading to a widespread pandemic characterized by multi-organ complications and failures. Aims: The present study was conducted to evaluate the impact of Pfizer and Sinopharm vaccines on metabolomic changes and their correlations with immune pathways. Main methods: The study used a cross-sectional design and implemented an untargeted metabolomics-based approach. Plasma samples were obtained from three groups: non-vaccinated participants, Sinopharm-vaccinated participants, and Pfizer-vaccinated participants. Comparative metabolomic analysis was conducted using TIMS-QTOF, and multiple t-tests with a 5 % false discovery rate (FDR) were performed using MetaboAnalyst software. Key findings: Out of the 105 metabolites detected, 72 showed statistically significant changes (p-value < 0.05) across the different groups. Notably, several metabolites such as neopterin, pyridoxal, and syringic acid were markedly altered in individuals vaccinated with Pfizer. Conversely, in the Sinopharm-vaccinated group, significant alterations were observed in sphinganine, neopterin, and sphingosine. These metabolites hold potential as biomarkers for evaluating vaccine efficacy. Additionally, both Pfizer and Sinopharm vaccinations were found to influence sphingolipid and histidine metabolisms compared to the control group. The Sinopharm group also displayed changes in lysine degradation relative to the control group. When comparing the enriched pathways between the Pfizer and Sinopharm-vaccinated groups, differences were observed in purine metabolism. Furthermore, alterations in tryptophan and vitamin B6 metabolism were noted when comparing the Pfizer-vaccinated group with both the control and Sinopharm-vaccinated groups. Significance: These findings highlight the importance of metabolomics in assessing vaccine effectiveness and identifying potential biomarkers for monitoring the efficacy of newly developed vaccines in a shorter timeframe.

Evaluation of Formalin-Inactivated Vaccine Efficacy against Red Seabream Iridovirus (RSIV) in Laboratory and Field Conditions.

Red seabream iridovirus (RSIV) is a major cause of marine fish mortality in Korea, with no effective vaccine available since its first occurrence in the 1990s. This study evaluated the efficacy of a formalin-killed vaccine against RSIV in rock bream under laboratory and field conditions. For the field trial, a total of 103,200 rock bream from two commercial marine cage-cultured farms in Southern Korea were vaccinated. Farm A vaccinated 31,100 fish in July 2020 and monitored them for 18 weeks, while farm B vaccinated 30,700 fish in August 2020 and monitored them for 12 weeks. At farm A, where there was no RSIV infection, the vaccine efficacy was assessed in the lab, showing a relative percentage of survival (RPS) ranging from 40% to 80%. At farm B, where natural RSIV infections occurred, cumulative mortality rates were 36.43% in the vaccinated group and 80.32% in the control group, resulting in an RPS of 54.67%. The RSIV-infectious status and neutralizing antibody titers in serum mirrored the cumulative mortality results. This study demonstrates that the formalin-killed vaccine effectively prevents RSIV in cage-cultured rock bream under both laboratory and field conditions.

Description of Clinical Outcomes of Janssen’s Ad26.COV2.S Prime and Single Boost for COVID-19 from January 2021 through July 2022 at a large Kentucky study site

Introduction The Janssen Ad26.COV2.S vaccine was developed to prevent SARS-CoV-2 illness. Phase 3 trials were initiated in 2020, including sites at the University of Kentucky, Norton Healthcare Louisville, and Baptist Health Lexington. This study followed non-immunosuppressed adult subjects through July 2022 to evaluate vaccine efficacy and safety, with a total of 1,094 participants. Methods Subjects aged 18 years or older, in good health, and without major immunological conditions were included. Three trials (ENSEMBLE-1, ENSEMBLE-2, and AMPLIFY) were conducted. Participants were evaluated for vaccine efficacy if they were nucleocapsid antibody-negative and had no prior COVID-19 infection at the time of their first booster. Vaccine regimens included a prime and single boost with Ad26.COV2.S or other combinations of prime and boost vaccinations, including mRNA vaccines. Results A total of 1,094 subjects were enrolled, with 903 subjects evaluated for vaccine efficacy. Among these, 431 received only a prime and single boost with Ad26.COV2.S, and 472 received other combinations of vaccines. During the study period, 174 COVID-19 infections occurred, with 95 (55%) being asymptomatic. The incidence of infections was similar between those who received only Ad26.COV2.S (94 infections) and those with other vaccination regimens (80 infections), with no significant difference (P &gt; .05). There were no serious vaccine-related safety concerns, and only one hospitalization occurred, involving a 75-year-old diabetic who recovered without intubation. Conclusion The Ad26.COV2.S vaccine, as a prime and single boost, demonstrated similar efficacy to other vaccination regimens in preventing COVID-19 infections. Both regimens provided protection against severe disease and hospitalization, with no significant safety concerns identified. This study supports the effectiveness and safety of the Ad26.COV2.S vaccine in the adult population during a period of high COVID-19 incidence.

Estimating vaccine efficacy during open-label follow-up of COVID-19 vaccine trials based on population-level surveillance data

While rapid development and roll out of COVID-19 vaccines is necessary in a pandemic, the process limits the ability of clinical trials to assess longer-term vaccine efficacy. We leveraged COVID-19 surveillance data in the U.S. to evaluate vaccine efficacy in U.S. Government-funded COVID-19 vaccine efficacy trials with a three-step estimation process. First, we used a compartmental epidemiological model informed by county-level surveillance data, a “population model”, to estimate SARS-CoV-2 incidence among the unvaccinated. Second, a “cohort model” was used to adjust the population SARS-CoV-2 incidence to the vaccine trial cohort, taking into account individual participant characteristics and the difference between SARS-CoV-2 infection and COVID-19 disease. Third, we fit a regression model estimating the offset between the cohort-model-based COVID-19 incidence in the unvaccinated with the placebo-group COVID-19 incidence in the trial during blinded follow-up. Counterfactual placebo COVID-19 incidence was estimated during open-label follow-up by adjusting the cohort-model-based incidence rate by the estimated offset. Vaccine efficacy during open-label follow-up was estimated by contrasting the vaccine group COVID-19 incidence with the counterfactual placebo COVID-19 incidence. We documented good performance of the methodology in a simulation study. We also applied the methodology to estimate vaccine efficacy for the two-dose AZD1222 COVID-19 vaccine using data from the phase 3 U.S. trial (ClinicalTrials.gov # NCT04516746). We estimated AZD1222 vaccine efficacy of 59.1% (95% uncertainty interval (UI): 40.4%–74.3%) in April, 2021 (mean 106 days post-second dose), which reduced to 35.7% (95% UI: 15.0%–51.7%) in July, 2021 (mean 198 days post-second-dose). We developed and evaluated a methodology for estimating longer-term vaccine efficacy. This methodology could be applied to estimating counterfactual placebo incidence for future placebo-controlled vaccine efficacy trials of emerging pathogens with early termination of blinded follow-up, to active-controlled or uncontrolled COVID-19 vaccine efficacy trials, and to other clinical endpoints influenced by vaccination.

Development of Non-toxic Recombinant Ricin Vaccine and Evaluation of Vaccine Efficacy

Ricin is a highly toxic protein which is produced in the seeds of the castor oil plant. Ricin toxin A chain has ribosomal RNA N-glycosylase activity that irreversibly hydrolyses the N-glycosidic bond of the adenine residue at position 4324 within the 28S rRNA. In this study, we developed non-toxic recombinant ricin vaccine(R51) in &lt;i&gt;E. coli&lt;/i&gt; expression system, and evaluated efficacy of the R51 according to adjuvants. When the R51 was administered using aluminum hydroxide as an adjuvant, the vaccine efficacy was higher than that of TLR agonists or aluminum phosphate. Because it is time-consuming to administer the vaccine three times at three-week intervals, we investigated the survival rate and antibody titer of mice according to the change of time interval of vaccination. Interestingly, there was no difference in survival rate and antibody titer when R51 was administered at 0, 1, and 3 weeks or 0, 2, and 4 weeks compared to when administered at 0, 3, and 6 weeks. Therefore, the developed R51 vaccine is promising to protect soldiers from Ricin attack.

HiBiT-tagged influenza A virus: a stable and efficient tool for antiviral reagent screening and vaccine evaluation

Influenza A viruses (IAVs) possess variable pathogenic potency causing great economic losses in the poultry industry worldwide and threatening public health. The control of IAV epidemics desperately necessitates an efficient platform for screening antiviral compounds and evaluating vaccine efficacy. In this study, we utilized the H9N2 subtype IAV as the working model. An 11-amino-acid HiBiT tag, derived from NanoLuc luciferase, was incorporated into the flexible linker region of the NS1 protein. Subsequently, the recombinant HiBiT-tagged virus was rescued. The recombinant virus exhibited high genetic stability and similar virological characteristics to the parental virus, both in vitro and in vivo. Of particular significance, the replication profile of the HiBiT-tagged virus can be easily measured using the Nano-Glo assay system, achieving an efficient screening platform. Based on this platform, we have developed assays with both convenience and efficiency for screening antiviral reagents, evaluating immunization efficacy, and measuring neutralizing antibodies.

Abstract 5007: Ex vivo evaluation of mRNA lipid nanoparticle cancer vaccines

Abstract Lipid nanoparticle vaccines have recently been developed broadly against pathogens and recently, in precision medicine targeting mutations in different tumors. Evaluating vaccine candidates typically require animal models using orthotopic or allogenic transplantations to evaluate efficiency. Evaluating vaccine efficacy using ex vivo systems is faster and less technically demanding. Here we aim to develop individualized cancer vaccines based on neoantigen identified within established human organoids or directly from patient tissue. The selected neoantigens are enriched for epitopes identified on gene fusions. Identified gene fusions encoding predicted immunogenic proteins are inserted into a vaccine backbone and used to make mRNA lipid nanoparticle vaccines. The neoantigen candidates are then evaluated in a personalized ex vivo testbed. Within the ex vivo testbed personal tumor neoantigens are tested on the patients own isolated CD8+ T cells and monocytes. Monocytes are in vitro differentiated into monocyte derived dendritic cells (moDCs), which specialize in antigen cross presentation. The moDCs are inoculated with mRNA lipid nanoparticle vaccines or loaded with peptides. The moDCs are then co-cultured with syngeneic T cells. Vaccine candidates are evaluated based on CD8+ T cell activation and cytotoxicity in the co-culture ex vivo testbed. Our pipeline offers a fast and efficient means of evaluating individualized vaccine candidates. Effective vaccines developed through this process can be administered as a standalone therapy or in combination with checkpoint inhibitors, to generate a strong durable immune response against a variety of solid tumor types. Citation Format: Tommy Lidström, Mara Blanco Arauzo, Nickolas Karlowatz, Mikael Johansson, Mattias Forsell, Jonas Nilsson. Ex vivo evaluation of mRNA lipid nanoparticle cancer vaccines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5007.

Utilizing murine dendritic cell line DC2.4 to evaluate the immunogenicity of subunit vaccines in vitro.

Subunit vaccines hold substantial promise in controlling infectious diseases, due to their superior safety profile, specific immunogenicity, simplified manufacturing processes, and well-defined chemical compositions. One of the most important end-targets of vaccines is a subset of lymphocytes originating from the thymus, known as T cells, which possess the ability to mount an antigen-specific immune response. Furthermore, vaccines confer long-term immunity through the generation of memory T cell pools. Dendritic cells are essential for the activation of T cells and the induction of adaptive immunity, making them key for the in vitro evaluation of vaccine efficacy. Upon internalization by dendritic cells, vaccine-bearing antigens are processed, and suitable fragments are presented to T cells by major histocompatibility complex (MHC) molecules. In addition, DCs can secrete various cytokines to crosstalk with T cells to coordinate subsequent immune responses. Here, we generated an in vitro model using the immortalized murine dendritic cell line, DC2.4, to recapitulate the process of antigen uptake and DC maturation, measured as the elevation of CD40, MHC-II, CD80 and CD86 on the cell surface. The levels of key DC cytokines, tumor necrosis alpha (TNF-α) and interleukin-10 (IL-10) were measured to better define DC activation. This information served as a cost-effective and rapid proxy for assessing the antigen presentation efficacy of various vaccine formulations, demonstrating a strong correlation with previously published in vivo study outcomes. Hence, our assay enables the selection of the lead vaccine candidates based on DC activation capacity prior to in vivo animal studies.

Neutralizing antibody levels detected early after mRNA-based vaccination do not predict by themselves subsequent breakthrough infections of SARS-CoV-2.

The development of mRNA vaccines represented a significant achievement in response to the global health crisis during the SARS-CoV-2 pandemic. Evaluating vaccine efficacy entails identifying different anti-SARS-CoV-2 antibodies, such as total antibodies against the Receptor Binding Domain (RBD) of the S-protein, or neutralizing antibodies (NAbs). This study utilized an innovative PETIA-based kit to measure NAb, and the investigation aimed to assess whether levels of anti-RBD IgG and NAb uniformly measured 30 days after vaccination could predict individuals at a higher risk of subsequent infection in the months following vaccination. Among a cohort of healthy vaccinated healthcare workers larger than 6,000, 12 mRNA-1273- and 115 BNT162b2-vaccinated individuals contracted infections after the first two doses. The main finding is that neither anti-RBD IgG nor NAb levels measured at day 30 post-vaccination can be used as predictors of breakthrough infections (BI). Therefore, the levels of anti-SARS-CoV-2 antibodies detected shortly after vaccination are not the pivotal factors involved in antiviral protection, and other characteristics must be considered in understanding protection against infection. Furthermore, the levels of anti-RBD and NAbs followed a very similar pattern, with a correlation coefficient of r = 0.96. This robust correlation would justify ceasing the quantification of NAbs, as the information provided by both determinations is highly similar. This optimization would help allocate resources more efficiently and speed up the determination of individuals' humoral immunity status.

Evaluation of vaccine efficacy with 2B/T epitope conjugated porcine IgG-Fc recombinants against foot-and-mouth disease virus.

The inactivated vaccine is effective in controlling foot-and-mouth disease (FMD), but it has drawbacks such as the need for a biosafety level 3 laboratory facility to handle live foot-and-mouth disease virus (FMDV), high production costs, and biological safety risks. In response to these challenges, we developed a new recombinant protein vaccine (2BT-pIgG-Fc) containing porcine IgG-Fc to enhance protein stability in the body. This vaccine incorporates two-repeat B-cell and one-single T-cell epitope derived from O/Jincheon/SKR/2014. Our study confirmed that 2BT-pIgG-Fc and a commercial FMDV vaccine induced FMDV-specific antibodies in guinea pigs at 28 days post-vaccination. The percentage inhibition (PI) value of 2BT-pIgG-Fc was 90.43%, and the commercial FMDV vaccine was 81.75%. The PI value of 2BT-pIgG-Fc was 8.68% higher than that of commercial FMDV vaccine. In pigs, the primary target animals for FMDV, all five individuals produced FMDV-specific antibodies 42 days after vaccination with 2BT-pIgG-Fc. Furthermore, serum from 2BT-pIgG-Fc-vaccinated pigs exhibited neutralizing ability against FMDV infection. Intriguingly, the 2BT-pIgG-Fc recombinant demonstrated FMDV-specific antibody production rates and neutralization efficiency similar to commercial inactivated vaccines. This study illustrates the potential to enhance vaccine efficacy by strategically combining well-known antigenic domains in the development of recombinant protein-based vaccines.

Detection and Diagnosis of Rift Valley Fever Virus.

Rift Valley fever virus (RVFV) is a globally important mosquito-borne virus that can also be directly transmitted via aerosolization of body fluids from infected animals. RVFV outbreaks cause mass mortality of young livestock and abortions in animals. In most severe human cases, the disease can progress to hemorrhagic fever and encephalitis, leading to death. RVF has a significant economic impact due to the loss of livestock that is a great challenge for people who depend on animals for income and food. Several vaccines are available for animal use, but none are yet licensed for use in human populations. This situation emphasizes the need to have robust and efficient diagnostic methods that can be used for early case confirmation, assessment of seroprevalence, and virus surveillance as well as vaccine efficacy evaluation. Despite the existence of different diagnostic methods for RVFV, we still have untimely reporting or underreporting of cases, probably due to lack of appropriate surveillance systems or diagnostic tools in some endemic countries. Here, we describe different methods available for detection and diagnosis of RVFV.

Surgical Primary Tumor Resection Reduces Accumulation of CD11b+ Myeloid Cells in the Lungs Augmenting the Efficacy of an Intranasal Cancer Vaccination against Secondary Lung Metastasis.

A hallmark of effective cancer treatment is the prevention of tumor reoccurrence and metastasis to distal organs, which are responsible for most cancer deaths. However, primary tumor resection is expected to be curative as most solid tumors have been shown both experimentally and clinically to accelerate metastasis to distal organs including the lungs. In this study, we evaluated the efficacy of our engineered nasal nano-vaccine (CpG-NP-Tag) in reducing accelerated lung metastasis resulting from primary tumor resection. Cytosine-phosphate-guanine oligonucleotide [CpG ODN]-conjugated nanoparticle [NP] encapsulating tumor antigen [Tag] (CpG-NP-Tag) was manufactured and tested in vivo using a syngeneic mouse mammary tumor model following intranasal delivery. We found that our nasal nano-vaccine (CpG-NP-Tag), compared to control NPs administered after primary mammary tumor resection, significantly reduced lung metastasis in female BALB/c mice subjected to surgery (surgery mice). An evaluation of vaccine efficacy in both surgery and non-surgery mice revealed that primary tumor resection reduces CD11b+ monocyte-derived suppressor-like cell accumulation in the lungs, allowing increased infiltration of vaccine-elicited T cells (IFN-γ CD8+ T cells) in the lungs of surgery mice compared to non-surgery mice. These findings suggest that the combination of the target delivery of a nasal vaccine in conjunction with the standard surgery of primary tumors is a plausible adjunctive treatment against the establishment of lung metastasis.