Search Results (4,400)

Background: Rabies is an almost universally fatal disease for which post-exposure prophylaxis (PEP), including passive immunization (PI) with rabies immunoglobulin or monoclonal antibodies, remains the only effective intervention. Despite established clinical guidelines, real-world PI utilization remains suboptimal. This study aimed to investigate the prevalence and determinants of PI hesitancy among previously unvaccinated patients with Category III rabies exposure in China. Methods: This multicenter cross-sectional questionnaire study was conducted at 12 rabies PEP clinics or emergency departments in 12 provinces of mainland China. The analysis included 585 previously unvaccinated adults with Category III rabies exposure who initially hesitated to receive or declined PI. The questionnaire collected sociodemographic characteristics, exposure profiles, awareness of the early protection gap, reasons for initial PI hesitancy or refusal, the decision to receive PI during the same clinical encounter, and PI product selection. Multivariable logistic regression identified factors associated with PI treatment decisions, with results reported as adjusted odds ratios (aORs); reason-specific models used the Benjamini–Hochberg false discovery rate correction. All inferential analyses were restricted to adults. Results: Among 5068 eligible previously unvaccinated patients with Category III rabies exposure, 2866 (57%) initially hesitated to receive or declined recommended PI. Of 617 questionnaire respondents, 32 minors were excluded, leaving 585 adults for all inferential analyses. The leading reasons for initial hesitancy were lack of understanding of the immediate protective role of PI (199/585, 34%), belief that vaccination alone was sufficient (194/585, 33%), and high cost (178/585, 30%). During the same clinical encounter, 320/585 adults (55%) chose to receive PI. Awareness of the early protection gap (aOR 2.63, 95% CI 1.75–3.98, p < 0.001) and bachelor’s degree or higher (aOR 1.61, 95% CI 1.07–2.43, p = 0.023) were positively associated with the decision to receive PI, whereas head/face wounds were negatively associated (aOR 0.53, 95% CI 0.30–0.92, p = 0.026). In reason-specific models, lack of knowledge about immediate protection was associated with higher odds of choosing PI (aOR 2.43, 95% CI 1.62–3.68, BH-FDR p < 0.001), whereas high cost was associated with lower odds (aOR 0.41, 95% CI 0.27–0.62, BH-FDR p < 0.001). Conclusion: Hesitancy toward and refusal of PI were observed among previously unvaccinated adults with Category III rabies exposure, yet initial hesitation or refusal is not irreversible. Early protection gap awareness was positively associated with PI choice, whereas cost-related concern was negatively associated. Clear explanation of protection timing and attention to cost-related barriers may support informed PI treatment decisions. Full article

Population immune pressure from vaccination and prior infection continues to drive the evolution of SARS-CoV-2. Systematic characterization of RBD mutations under complex immune backgrounds is essential for understanding viral adaptation and evolutionary trajectories. Here, we applied a deep mutational scanning (DMS) to comprehensively map the neutralization escape landscape of the Omicron variant JN.1 and its descendant lineage XEC, under immune pressure from individuals who experienced Omicron breakthrough infections following three doses of inactivated vaccines. A neutralization escape map for the single amino acid substitutions in the RBD of JN.1 or XEC was generated, and the escape efficiency of each mutation was determined. The results show that RBD escape mutations are hierarchically organized: low-intensity signals are widespread, whereas high-intensity escape is confined to a few key sites. These escape mutations are not confined solely to the receptor-binding motif (RBM) but are broadly distributed across the entire RBD. Many escape sites could accommodate multiple amino acid substitutions. Integration of DMS data with genomic surveillance of circulating variants from 2024 to 2025 revealed significant overlap between experimentally identified escape sites and mutations observed in natural isolates. This overlap increased substantially in 2025, with site concordance rising from 27.17% and 26.81% to 45.09% and 47.10% for JN.1 and XEC, respectively. The natural prevalence of these escape mutations is further shaped by factors such as receptor-binding affinity, protein stability, and epistatic interactions. Overall, our findings suggest that SARS-CoV-2 antigenic evolution follows the pattern of multiple pathways within a constrained space, providing new insights into the adaptive mechanisms of Omicron-derived variants under hybrid immune pressure. Full article

Background/Objectives: Food allergy prevention is no longer understood as the simple avoidance of allergenic foods. The first 1000 days (from conception to, approximately, 24 months of age) include prenatal, perinatal and postnatal windows in which diet, epithelial barrier integrity, microbial ecology, immune maturation and family-level implementation interact. This narrative review was developed as a Commission-proposed SIAIP-oriented clinical framework, rather than a formal guideline or consensus statement. Evidence from guidelines, systematic reviews, randomised trials, birth cohorts and mechanistic studies was organised by developmental window and interpreted according to endpoint validity, confounding, feasibility and clinical readiness. Prenatal factors include maternal allergen non-avoidance, whole-diet quality, micronutrient and fatty acid status, antibiotic exposure, environmental context and maternal microbiome. Perinatal factors include mode of delivery, intrapartum and neonatal antibiotics, gestational maturity, early colonisation, breastfeeding initiation and routine vaccination. Postnatal factors include eczema, skin barrier inflammation, the timing and regularity of allergen introduction, breastfeeding management, infant diet diversity, siblings, daycare, pets, smoke and pollution, physical activity and equitable implementation. The strongest actionable evidence remains eczema-linked risk recognition and timely, sustained oral exposure to peanut and well-cooked egg. Maternal and environmental factors are clinically important, but many are contextual rather than prescriptive; they should guide non-restrictive, non-blaming counselling rather than deterministic risk labelling. Full article

Background/Objectives: Neurocognitive disorders represent a growing burden among older adults. Although respiratory vaccines have demonstrated efficacy and safety in preventing acute respiratory events, their potential impact on the development of chronic neurocognitive disorders, such as cognitive impairment, dementia, and Alzheimer’s disease (AD), has not been extensively explored. The objective of this scoping review was to synthesize and analyze the available evidence on the association between respiratory vaccination and the risk of developing cognitive impairment, dementia, and Alzheimer’s disease. Methods: A scoping review was conducted in accordance with the PRISMA-ScR guidelines. A literature search was performed in the PubMed, Scopus, and Web of Science databases through 15 June 2026. Studies involving older adults (≥60 years), irrespective of their baseline neurocognitive status, were included. Observational studies (cohort and case–control studies) were considered. Editorials, narrative reviews, and other non-original articles were excluded. Results: Eighteen studies were included, with cohort studies being the predominant design. Four main categories of respiratory vaccines were evaluated: influenza, COVID-19, respiratory syncytial virus (RSV), and pneumococcal vaccines, in relation to the risk of cognitive impairment, dementia, and AD. Influenza vaccination was associated with a lower risk of dementia and AD, with a potential dose–response relationship observed, whereby a greater number of vaccinations was associated with a greater reduction in risk. Pneumococcal vaccination was also associated with a lower risk of dementia and AD, particularly among individuals who received a greater number of vaccine doses. In contrast, the evidence regarding COVID-19 and RSV vaccines was limited and yielded heterogeneous findings. Conclusions: Influenza and pneumococcal vaccination maybe associated with a lower risk of Alzheimer’s disease and dementia. However, the evidence regarding COVID-19 and RSV vaccines remains limited, and additional studies are needed to clarify their impact on the risk of developing neurocognitive disorders. Full article

Background: The number of vaccines recommended for adults and older people has increased in recent years, and same-visit coadministration represents a potential strategy to improve vaccination coverage and timeliness. However, its implementation in primary care may depend on general practitioners’ (GPs) attitudes, vaccination experience, and organisational factors. This study investigated knowledge, attitudes, and practices (KAP) regarding vaccine coadministration among GPs in Apulia, Southern Italy. Methods: We conducted an anonymous cross-sectional online survey between January and June 2026 among practicing GPs and general practice trainees working in outpatient primary care settings in Apulia. The questionnaire assessed vaccination activity, intended coadministration practices, perceived effects on vaccine effectiveness and coverage, safety in very old adults or patients with multimorbidity, and perceived barriers to vaccination. Descriptive and bivariate analyses were performed, followed by multivariable logistic regression to identify factors independently associated with a positive perception of coadministration safety in very old or multimorbid patients. An additional sensitivity analysis excluded respondents reporting insufficient information to assess safety. Results: A total of 256 physicians completed the survey; 71.1% were aged ≥50 years. Most respondents had administered adult vaccines during the previous year, and 68.0% were classified as high vaccinators, having administered three or more different vaccine types. Although 68.0% believed that coadministration could increase vaccination coverage, only 13.3% reported willingness to administer three or more vaccines during a single visit. Overall, 50.0% considered coadministration very or fairly safe in very old or multimorbid patients, 24.2% considered it slightly or not at all safe, and 25.8% reported insufficient information to assess its safety. In the fully adjusted model, high vaccination activity was associated with higher odds of a positive safety perception (adjusted odds ratio [aOR] 1.93, 95% confidence interval [CI] 1.01–3.70), whereas difficulties using vaccination IT platforms were associated with lower odds (aOR 0.48, 95% CI 0.26–0.86). Age ≥ 50 years was not independently associated with the outcome after adjustment (aOR 0.66, 95% CI 0.35–1.26). Conclusions: GPs in Apulia showed generally favorable attitudes toward vaccine coadministration, although substantial uncertainty remained regarding its use in very old and multimorbid patients. Confidence in coadministration was primarily associated with greater vaccination activity and fewer difficulties with vaccination IT platforms, whereas age-related differences observed in bivariate analyses were attenuated after multivariable adjustment. Educational, organisational, and digital-support interventions may facilitate broader implementation of same-visit adult vaccination in primary care. Full article

Background/Objectives: Particulate vaccine formulations require delivery systems and immunostimulatory components that support antigen-presenting cell interaction while maintaining formulation stability and cytocompatibility. This study examines Guanine-α-D-Fructose (GDF), a guanine–fructose small-molecule immunostimulatory candidate, incorporated into poly(lactic acid-co-glycolic acid) (PLGA) microparticles and benchmarked in vitro against established adjuvant formulations containing Alum or AddaVax. Methods: GDF-loaded microparticles were prepared and characterized for particle size, morphology, surface charge, entrapment efficiency, and release behavior. Their in vitro immunostimulatory activity was evaluated using murine dendritic cells. To explore formulation compatibility, GDF MPs were tested in combination with multiple particulate antigen formulations, including measles, gonorrhea, SARS-CoV-2, influenza A (H3N2), and Zika. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was utilized to measure cell viability, while nitric oxide generation was measured with the Griess assay. Dendritic cell activation-associated surface marker expression was analyzed by flow cytometry using MHC I, MHC II, CD80, and CD40. Results: The particles showed consistent spherical morphology, sustained GDF release, and favorable cytocompatibility at concentrations up to 250 µg/mL, with reduced viability at higher concentrations. GDF MPs increased nitric oxide production and activation-associated marker expression, with responses benchmarked against Alum and AddaVax and comparable in several assay conditions. Increased autophagosome-associated fluorescence was also observed, suggesting modulation of autophagy-related cellular activity; however, direct antigen-processing or antigen-presentation assays are still required. Conclusions: Overall, these findings support GDF-loaded PLGA microparticles as an in vitro immunostimulatory particulate formulation suitable for further mechanistic and in vivo evaluation in vaccine-related systems. Full article

Background/Objectives: Mosquito-borne viruses cause substantial global morbidity and mortality. Mosquito saliva, secreted during biting, facilitates blood feeding and can enhance virus infection. Here, we evaluated whether combining virus-specific antigens with mosquito salivary protein-derived peptides improves protection in Zika virus (ZIKV) and chikungunya virus (CHIKV) mouse models. Methods: Peptides from Aedes and Culex salivary proteins were selected based on conservation, predicted T-cell reactivity, and cellular and humoral immunogenicity in mice. Mice were immunised subcutaneously with a prime and boost two weeks apart using adjuvanted salivary peptides (SAL), commercial ZIKV- or CHIKV-like particles (VLPs), or salivary peptides combined with the relevant VLPs. Vaccine doses contained 0.5 µg VLPs and/or 10 nmol of each salivary peptide, formulated with Montanide ISA-51; when combined, VLPs and SAL were administered on opposite flanks. Two weeks after boosting, mice were challenged with ZIKV or CHIKV plus Aedes aegypti saliva. Challenge teams were blinded to group allocation until data analyses were complete. Results: SAL enhanced the protective effect of VLP vaccination compared with VLPs alone. In the CHIKV model, CHIKV VLP + SAL prevented joint swelling and reduced infectious virus in the inoculated ankle and viral RNA in the contralateral ankle. In the ZIKV model, ZIKV VLP + SAL reduced viral RNA in skin and brain tissue and improved survival. Conclusions: Mosquito salivary peptide antigens improved the protective efficacy of VLP vaccines against ZIKV and CHIKV in mouse models. Salivary antigens may provide a complementary vaccine component for multiple arboviruses transmitted by Aedes and Culex mosquitoes. Full article

Background/Objectives: Autoimmune and immune-mediated adverse events coded in reports listing COVID-19 vaccines as suspect products are rare, heterogeneous, and difficult to evaluate in spontaneous reporting systems. We characterized autoimmune reporting signals using strict case definitions and an active-comparator disproportionality design. Methods: FAERS reports from 2021Q1 to 2023Q4 were deduplicated and harmonized by vaccine product, platform, sex, age group, and MedDRA Preferred Term (PT). COVID-19 vaccine reports recorded as primary or secondary suspect products were compared with traditional non-COVID vaccine reports. Strict autoimmune events were grouped into neurological, endocrine, rheumatological, hematological, dermatological, and cardiac categories. Reporting odds ratios (RORs), proportional reporting ratios (PRRs), PT-level rankings, masking audits, and sensitivity analyses were evaluated. Results: The primary analysis included 4191 COVID-19 vaccine reports, 2817 comparator reports, and 311 strict-autoimmune reports contributing 316 report-category observations. Positive category-level signals were identified for dermatological (ROR 10.49; 95% CI: 2.51–43.86), endocrine (ROR 5.39; 95% CI: 1.24–23.48), hematological (ROR 4.68; 95% CI: 2.32–9.44), and neurological events (ROR 1.63; 95% CI: 1.16–2.29). Rheumatological reporting was lower, strict cardiac events were absent, and hematological signals were most consistent across sensitivity analyses. Among five adjusted-positive finite PT signals, immune thrombocytopenia was more stable, multiple sclerosis intermediate, and acquired hemophilia, myasthenia gravis, and optic neuritis sparse/imprecise. A post hoc audit identified four potential clusters among 20 acquired-hemophilia reports; cluster collapse reduced the ROR to 2.70 (95% CI 0.30–24.18; p = 0.654). Conclusions: These findings are hypothesis-generating and do not establish incidence, absolute risk, or causality. Full article

Background/Objectives: Human adenoviruses (HAdVs) are widely used as vectors for vaccines and gene therapy; however, pre-existing immunity can reduce their efficacy. Therefore, rapid and accessible serological methods are required to assess antibody levels against adenoviruses. Lateral flow immunochromatographic assay (LFIA) sensitivity depends on the label and antigen. In this study, we aimed to develop and evaluate LFIA systems based on gold nanoparticles (GNPs) and quantum dots (QDs) using a recombinant HAdV hexon protein. Methods: A recombinant HAdV hexon protein fragment (rhHAdV, 35 kDa; amino acids A120-R316) was expressed in Escherichia coli and purified using Ni²⁺ affinity chromatography. Protein identity was confirmed using sodium dodecyl sulfate–polyacrylamide gel electrophoresis, Western blotting, and liquid chromatography–tandem mass spectrometry analyses. Two LFIA formats were developed using Protein G-conjugated GNPs (GNP-G) and QDs (QD-G). Agreement with the reference ELISA was evaluated using 90 human serum samples. Results: The rhHAdV antigen demonstrated reactivity with anti-adenovirus-positive human sera in ELISA. Antibody detection was achieved at serum dilutions of up to 1:300 and 1:1000 for the GNP- and QD-based LFIA, respectively. The GNP-G and QD-G LFIA formats demonstrated positive percent agreements of 96.9% and 100%, respectively, while both assays showed a negative percent agreement of 98.2% compared with the reference ELISA. Conclusions: The findings demonstrate the feasibility of a QD-based LFIA for qualitative detection of antibodies reactive with the recombinant HAdV-B3 hexon fragment. Full article

Background/Objectives: Post-COVID syndrome (PCS) remains a clinically heterogeneous condition. In patients with chronic diseases, real-world evidence is needed to describe its frequency and to identify clinical factors associated with its current presence. This study assessed the prevalence of PCS and factors associated with current PCS status among patients with chronic diseases. Methods: This observational cross-sectional study included a consecutively enrolled source clinical sample of 850 adults receiving inpatient or outpatient care in Almaty and the Almaty Region between June and December 2025. The primary analytic cohort comprised participants with documented prior COVID-19 (n = 250). PCS was assessed at study enrollment according to the national clinical protocol as current symptoms persisting for more than 12 weeks and not explained by an alternative diagnosis. Multivariable logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). COVID-19 vaccination was excluded from the primary model and evaluated only in a sensitivity analysis because vaccination timing relative to infection was unavailable. The exploratory association-based probability model was evaluated using the AUC with 95% CI, Brier score, calibration assessment, bootstrap internal validation with 1000 resamples, assessment of age nonlinearity, and decision curve analysis. Results: PCS was identified in 147 of 250 participants with prior COVID-19 (58.8%). In the revised primary multivariable model, age (OR = 1.24 per 10-year increase; 95% CI: 1.01–1.54; p = 0.040) and endocrine diseases (OR = 3.36; 95% CI: 1.69–6.98; p < 0.001) remained associated with current PCS status. The association with endocrine diseases persisted after adjustment for body mass index. The apparent AUC was 0.687 (95% CI: 0.620–0.753), and the Brier score was 0.218. Bootstrap internal validation yielded an optimism-corrected AUC of 0.655, a calibration intercept of 0.061, and a calibration slope of 0.816. Conclusions: PCS was frequent among patients with chronic diseases who had prior COVID-19. Older age and endocrine pathology were the most consistent factors associated with current PCS status. All model-performance estimates were obtained within the development sample; the model should not be used for individual prediction or follow-up planning without prospective external validation. Full article

Background: This study evaluated vaccine prescription conversion and identified associated factors in Henan Province, China, during 2025. Methods: The study was conducted in Lingbao City, Henan Province. All vaccine prescriptions issued in 2025 were collected, and vaccination status was linked through the Henan Provincial Immunization Information Management System. Subgroup analyses were stratified by vaccine type (NIP vs. non-NIP). Univariate analyses used χ², Mann–Whitney U, and Kruskal–Wallis H tests. Multivariable analyses employed Firth-corrected logistic regression for conversion behavior, and mixed-effects models with random intercepts for patient ID for conversion timeliness, analyzed using a two-part model. All analyses were performed using R software (version 4.5.3). Results: Among 50,887 prescriptions, the overall conversion rate was 13.8%. NIP vaccines had a higher conversion rate than non-NIP vaccines (76.8% vs. 12.5%, p < 0.001) and a higher same-day conversion rate (13.9% vs. 7.4%; χ² = 59.585, p < 0.001), but longer delays among non-same-day conversions (23 vs. 4 days). Manual prescriptions were associated with significantly higher conversion in both NIP (OR = 3.913) and non-NIP (OR = 37.720) subgroups. Vaccination clinics were associated with a nearly 20-fold higher odds (OR = 19.386). Interaction analyses showed manual prescriptions were more strongly associated with conversion and shorter delays in older adults, and had stronger associations with conversion for non-NIP vaccines (χ² = 22.275, p < 0.001). Vaccination clinics were most strongly associated with conversion in children (ΔP = 0.130); however, the improvement in same-day conversion among older adults was relatively smaller, suggesting additional barriers beyond clinic availability may exist in this population. Conclusions: Manual prescriptions and vaccination clinics were associated with higher vaccine prescription conversion, with particularly pronounced effects on non-NIP vaccines. Older adults exhibited the lowest conversion rates. In parallel with promoting electronic prescriptions, co-issuing paper prescriptions is recommended, particularly for non-NIP vaccines and older adults. Full article

Background: Pakistan is one of only two countries where wild poliovirus type 1 (WPV1) continues to persist. Vaccine refusals challenge efforts to end the virus, especially in high-risk communities. Methods: A qualitative exploratory study took place from September to November 2025 in three High-Risk Union Councils (HRUCs) of Karachi, Pakistan. The study examined reasons for refusing the polio vaccine and identified specific communication and operational strategies to improve vaccine acceptance. A total of 23 in-depth interviews and 10 focus group discussions were conducted with 71 participants, including parents who refuse the vaccine, polio program staff, physicians, and government stakeholders. Data were analyzed using a sequential inductive and deductive thematic approach, mapping findings onto the Socio-Ecological Model (SEM) with NVivo 15 (Lumivero, Denver, CO, USA). Results: Factors influencing polio vaccine refusals were interconnected and spanned multiple levels. At the intrapersonal level, campaign fatigue, a lack of knowledge about poliomyelitis, concerns about side effects, and rumors about infertility were common. Community-level factors included household gatekeepers, local influencers, and digital misinformation. Institutional barriers included weak communication from the frontline, inadequate supervision, workforce shortages, poor tracking of refusals, and limited involvement of physicians. At the policy level, refusals were linked to distrust in governance, poor municipal services, and dissatisfaction with vertical campaign methods. Recommended strategies included integrating polio services with routine immunization and primary healthcare, strengthening counseling by physicians, engaging trusted local influencers and community leaders, expanding targeted social media campaigns to counter misinformation, implementing quick responses to rumors, enhancing workforce capacity, and using data-driven microplanning, including targeted SNIDs and focused interventions in areas with chronic refusals. Conclusions: Polio vaccine refusals are shaped by social, communication, operational, and structural factors. Improving communication and operational guidelines by reducing the number of campaigns, increasing active engagement at the frontline, integrating polio activities into routine health services, and addressing misinformation with a dynamic communication strategy may enhance vaccine acceptance and support polio eradication efforts. Full article

Background: Pancreas disease, caused by salmonid alphavirus subtype 3 (SAV3), remains a significant threat to Atlantic salmon (Salmo salar L.) aquaculture in Norway despite the widespread use of inactivated vaccines. Molecular adjuvants represent a promising strategy to improve vaccine efficacy by enhancing immune responses. Methods: In this study, we evaluated the immunological and protective effects of two transcription factors, gata3 and eomes encoded by plasmid DNA adjuvants in combination with a low-dose inactivated SAV3 vaccine. Atlantic salmon were immunized with inactivated virus alone or in combination with either gata3- or eomes-encoding plasmids, followed by SAV3 challenge. Vaccine performance was assessed by growth, antibody response (ELISA and virus neutralization assay), and histopathological scoring of heart and pancreas. Results: The effects of gata3 and eomes were context-dependent: eomes reduced pancreas lesions at 4 weeks post-challenge, while both plasmid-adjuvant groups showed improved growth at 10 weeks post-challenge compared to the plasmid control. Although antibody responses were increased in all vaccinated groups at 6 weeks post-immunization, the plasmid control performed comparably to the GATA3 or EOMES groups, and no significant differences were detected in the virus neutralization test. Interestingly, the empty plasmids given to control fish exhibited immunostimulatory activity, warranting further investigation. In vitro and in vivo fluorescence microscopy confirmed expression of the transcription factors in transfected cells and at the injection site. Conclusions: Our results suggest that transcription factor-encoding plasmids can provide selective adjuvant effects, while also highlighting the potential that plasmid DNA can have as adjuvants in fish vaccine development. Full article

Background/Objectives: Nipah virus (NiV) is a highly pathogenic zoonotic agent that causes fatal respiratory and neurological diseases, for which no approved vaccines are currently available. To address this unmet need, we developed and evaluated novel mRNA-LNP vaccine candidates. These vaccines employ an epitope- and structure–guided “immune-focusing” strategy, aiming to maximize the exposure of critical neutralizing epitopes on the viral attachment (G) and fusion (F) glycoproteins. Methods: Head-to-head dimeric antigens (2Gs and 2Fs) were engineered by removing subdominant stalk regions and tandemly duplicating epitope-rich globular head domains. Three LNP-encapsulated candidates-NV1 (encoding 2Gs), NV2 (encoding 2Fs), and NV3 (a 1:1 mixture of NV1 and NV2)-were evaluated in BALB/c mice and Syrian hamsters to systematically assess humoral responses, cytokine secretion, BCR/TCR repertoires, and systemic safety. Results: NV1 and NV3 induced potent binding antibodies and strong neutralizing activity against NiV pseudoviruses. Meanwhile, although NV2 lacked neutralizing activity, it induced superior Th1-biased cellular immunity, accompanied by extensive T-cell clonal proliferation. BCR/TCR sequencing revealed unique adaptive immune characteristics that perfectly align with the distinct immunogenic properties described above. Preliminary safety assessments found no toxicity to vital organs, while active germinal center formation confirmed the success of immune mobilization. Conclusions: An epitope-centered dimer design effectively shapes the unique defense mechanisms of the adaptive immune system. NV3 offers a balanced and synergistic strategy that combines potent humoral and cellular immune defenses, providing a highly promising platform for the development of a Nipah virus (NiV) vaccine. Full article

Background: Staphylococcus aureus (SA) causes septicemia and arthritis, eventually resulting in substantial economic losses and health hazards in poultry. Lethal electron beam (eBeam) treatment kills bacteria while preserving surface epitopes. Methods: This study compared broiler chicken immune responses (local and systemic) after eBeam-killed (eB) or formalin-killed (FK) SA injections. The vaccine (sham) control was endotoxin-free PBS. This study contained six treatments (trt) with five chickens/trt, with vaccine trts divided into two groups, A and B. Group A received in ovo vaccine/sham treatments (phase 1) initially. At 34 d of age, the pulps of growing feathers (GFs) received intradermal (i.d.) injections of the respective trt to elicit booster and primary responses in groups A and B, respectively. Blood was collected to analyze leukocyte populations and plasma SA-specific antibody levels. Additionally, in phase 2, GFs were collected to assess leukocyte presence in GF pulps. Two-way ANOVA was conducted to test the effects of treatment, time, and their interactions, followed by Tukey’s HSD tests at p < 0.05 for statistical significance. Results: Early in phase 1, the eB group had increased SA-specific IgM, IgA, and total lymphocyte concentrations compared with FK. In phase 2, FK and eB i.d. vaccines increased total lymphocyte and T cell proportions in GF pulps compared with sham. In blood, the recall eB vaccination increased monocytes, B cells, CD8+ T cells, and total lymphocytes, while the recall FK vaccination increased heterophils (p < 0.05). Conclusions: Improved early protection at mucosal surfaces may be reflected by higher plasma levels of SA-specific IgM and IgA following in ovo eBeam-killed-SA vaccination. Additionally, both eB-SA and FK-SA vaccines stimulated robust local inflammatory responses dominated by lymphocytes in GF pulps. Full article