Search Results (19,202)

Background and Objectives: Severe COVID-19 frequently fulfills Sepsis-3 criteria and is characterized by thrombo-inflammation and endothelial injury. We evaluated whether a bedside endothelial activation index (EAI = D-dimer/fibrinogen) identifies biologically distinct phenotypes and relates to interleukin-6 (IL-6) response after therapeutic plasma exchange (TPE), and whether baseline IL-6 predicts a ≥50% IL-6 reduction. Methods: Retrospective single-center ICU cohort of adults with SARS-CoV-2 infection, sepsis-related organ dysfunction, and ≥1 TPE session (n = 51). Patients were stratified by median EAI (low vs. high). Outcomes included peri-procedural biomarker/physiology changes (post–baseline), IL-6 responder status (≥50% reduction), correlations with IL-6 reduction (%), and multivariable predictors of response. Results: Compared with low EAI (n = 25), high EAI (n = 26) had higher baseline D-dimer (6.2 vs. 2.2 µg/mL) and lower fibrinogen (2.9 vs. 7.1 g/L) (both p < 0.001). Low EAI showed larger CRP decreases (ΔCRP −84.0 vs. −2.3 mg/L; p = 0.001) and larger fibrinogen falls (Δ −3.1 vs. −0.4 g/L; p < 0.001), while high EAI had larger D-dimer decreases (Δ −2.5 vs. −0.6 µg/mL; p = 0.004) and a modest SOFA improvement (Δ −0.3 vs. +0.1; p = 0.026). IL-6 responders (n = 20) had higher baseline IL-6 than non-responders (365.2 vs. 47.1 pg/mL; p < 0.001). Baseline IL-6 independently predicted response (per doubling: OR 1.94, 95% CI 1.27–2.95; p = 0.002), while age reduced odds (OR 0.91/year, 95% CI 0.84–0.99; p = 0.032). IL-6 reduction correlated with ΔCRP (ρ = −0.41; p = 0.003) and ΔPaO₂/FiO₂ (ρ = 0.37; p = 0.01). Conclusions: EAI stratifies distinct thrombo-inflammatory patterns around TPE, while baseline IL-6 is the dominant predictor of achieving large IL-6 reductions. To emphasize the novelty and clarify the study objective, this exploratory analysis used a phenotype-stratified framework to test whether a simple bedside endothelial activation index could enrich biological response assessment to adjunctive TPE. The prespecified primary outcome was achievement of a ≥50% IL-6 reduction after completion of the TPE course; secondary outcomes included peri-procedural biomarker, oxygenation, SOFA, and ICU endpoints. Full article

Background and Objectives: Coronavirus disease 2019 (COVID-19) is characterized by excessive inflammatory responses, including the so-called cytokine storm, which contributes substantially to morbidity and mortality in hospitalized patients. The vagus nerve, through the cholinergic anti-inflammatory pathway, represents a theoretically attractive therapeutic target for modulating systemic inflammation. Vagus nerve stimulation (VNS) has emerged as a potential adjunctive treatment for COVID-19, with several randomized controlled trials (RCTs) investigating its efficacy on inflammatory biomarkers and clinical outcomes. The quality of this evidence base has not been rigorously evaluated. This systematic review critically appraises all available RCT evidence for VNS in hospitalized COVID-19 patients. Materials and Methods: We systematically searched PubMed, Scopus, Cochrane (CENTRAL), and Web of Science from database inception to January 2026, for RCTs evaluating any form of VNS (invasive, non-invasive, cervical, or auricular) in hospitalized patients with confirmed acute COVID-19. Two reviewers independently screened titles, abstracts, and full texts according to pre-specified eligibility criteria. Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, with assessments initially performed using multiple artificial intelligence tools and subsequently validated by the authors in accordance with PRISMA 2020 guidelines. Given substantial heterogeneity and high risk of bias, narrative synthesis was performed rather than meta-analysis. Also, GRADE assessment was performed. Results: From 437 records identified, six RCTs comprising 221 patients met the inclusion criteria. Five trials (83%) were rated as high risk of bias, primarily due to inadequate blinding, substantial baseline imbalances, significant missing data and extensive multiple testing without statistical correction. The single double-blind trial with a credible sham control (Rangon et al.) found null results across all outcomes, including clinical progression, ICU transfer, and mortality, while the five “high” risk-of-bias trials generally reported positive findings on various inflammatory markers and clinical outcomes. One trial (Corrêa et al.) measured heart rate variability as a direct indicator of vagal activation and found no change despite claiming anti-inflammatory effects, contradicting the proposed mechanism of action. Significant cognitive findings from an interim analysis (Uehara et al., n = 21) disappeared in the larger completed trial (Corrêa et al., n = 52), providing empirical demonstration of false positive findings in small, underpowered studies. Conclusions: Currently available evidence supporting the use of VNS for acute COVID-19 remains scarce; however, the physiological rationale remains sound, although the absence of reliable target engagement markers in the included studies limits confidence in this treatment method. Large-scale, double-blind, sham-controlled trials are required before VNS can be firmly recommended for COVID-19 management. Full article

The translation of nucleic acid amplification into practical point-of-care and biosensor-integrated diagnostics is still significantly impeded by the necessity for rapid sample preparation. For this reason, a broad comparison of seven commercially available kits for DNA/RNA extraction containing their temperature-related adjustments was performed. Extracts isolated from SARS-CoV-2-positive nasopharyngeal swabs, viral stocks, as well as laboratory-prepared suspensions of clinically relevant Gram-positive and Gram-negative bacteria were evaluated by recombinase polymerase amplification (RPA) and real-time PCR. In addition, the impact of transport media for SARS-CoV-2 samples was investigated. Extraction performance varied markedly according to the kit, pathogen, sample background. For SARS-CoV-2, rapid extraction was more effective for samples collected in viral transport medium than in inactivation buffer. Across bacterial targets, performance was species dependent, highlighting substantial differences in compatibility between simplified extraction workflows and downstream amplification. Among the rapid methods tested, a simplified QuickExtract protocol (95 °C, 5 min) provided the most consistent overall results, although it did not uniformly match the reference silica-based method for all targets. In conclusion, these results demonstrate that rapid nucleic acid extraction must be thoroughly evaluated as an essential element of the entire sample-to-answer workflow, rather than being chosen as a standalone preprocessing step for point-of-care molecular diagnostics. Full article

Background/Objectives: Understanding the relationship between reactogenicity and immunogenicity after repeated BNT162b2 vaccination is critical for optimizing vaccination strategies. This study quantified their progressive dissociation across four vaccine doses. Methods: We conducted a prospective longitudinal cohort study among Croatian healthcare workers vaccinated with BNT162b2 from January 2021 to January 2024. Anti-SARS-CoV-2 IgG antibodies were measured at 16 timepoints using chemiluminescent immunoassay. Local (pain, erythema, swelling) and systemic (fever, fatigue, headache, myalgia, arthralgia, nausea) reactions were recorded for 7 days using FDA toxicity scale. Correlations were analyzed with Spearman’s method and Bonferroni correction. Fourth-dose responses were predicted by exponential modeling. Results: Of 631 participants, 524 completed primary immunization, 418 received a third dose (173 with complete data), and 56 received a fourth dose (22 with complete paired data). Local reactions declined from 82.4% after the first dose to 42.9% after the fourth (p < 0.001). Systemic reactions peaked at 44.8% after the second dose, then decreased to 26.0% after the third and 19.6% after the fourth. In contrast, median antibody levels rose from 9910 AU/mL after the primary series to 29,002 AU/mL after the third and 38,274 AU/mL after the fourth. Correlations between reactions and antibody titer progressively weakened: r = 0.37 (95% CI 0.29–0.44, p < 0.001) after the primary series, r = 0.08 (95% CI −0.07 to 0.23, p = 0.30) after the third, and r = 0.04 (95% CI −0.39 to 0.45, p = 0.86) after the fourth dose. Conclusions: Progressive dissociation between reactogenicity and immunogenicity was observed across four BNT162b2 doses. Booster doses maintain robust antibody responses despite reduced reactogenicity, reinforcing that minimal side effects are consistent with sustained humoral responses. Full article

Background/Objectives: Maternal postpartum depressive symptoms and the COVID-19 pandemic have both been identified as potential risk factors for socioemotional difficulties in children. This study aimed to assess behavioral outcomes in young children born to mothers previously screened for postpartum depressive symptoms, comparing cohorts evaluated during and after the pandemic using the Child Behavior Checklist (CBCL 1½–5). Methods: An observational follow-up cohort study was conducted on 52 mother–child dyads derived from a previously established maternal cohort screened with the Edinburgh Postnatal Depression Scale (EPDS). Two cohorts were defined according to the child’s birth period: during-pandemic (January–April 2022) and post-pandemic (October–November 2023) groups. Behavioral outcomes were assessed using CBCL 1½–5. Group differences were tested using parametric or non-parametric methods for continuous variables and χ2 or Fisher’s exact tests for categorical variables. Exploratory regression models and sensitivity analyses were also performed. Results: Children assessed in the post-pandemic cohort showed a lower prevalence of non-normal internalizing scores than those assessed in the during-pandemic cohort, whereas externalizing outcomes and Total Problems did not significantly differ between groups. In exploratory models, a child’s age showed a near-significant association with internalizing outcomes, suggesting that developmental stage at assessment may have contributed to the observed cohort difference. Maternal SARS-CoV-2 infection at delivery was not associated with children’s behavioral outcomes. Conclusions: These findings suggest a possible difference in internalizing behavioral profiles between children assessed in during-pandemic and post-pandemic cohorts. However, this pattern should be interpreted cautiously because the cohorts differed substantially in age at follow-up, and age-related factors may have affected symptom detectability. Continued longitudinal follow-up will be important to clarify whether the observed differences persist over time. Full article

Background: An unfavorable course of SARS-CoV-2 infection can lead to significant morbidity and mortality. The study aimed to develop a simple, accessible, and reliable tool to anticipate the poor results among COVID-19 pneumonia patients. Methods: This retrospective cohort study involves 306 individuals with severe COVID-19 pneumonia enrolled between March 2021 and June 2021. Each patient had confirmed SARS-CoV-2 infection and required oxygen therapy. Differential blood count and serum CRP were taken on admission day. Medical data were collected from the hospital’s information system. Results: Of 306 patients (133 females, 173 males, aged 66.3 ± 15.2 years), 105 (34.3%) died. Counts of neutrophils, lymphocytes, and eosinophils differed significantly between survivors and deceased (p < 0.001; p = 0.002; p = 0.009, respectively) and had substantially differentiating properties in ROC analysis. Built with the counts of neutrophils, lymphocytes, and eosinophils, the White Blood Cell Score (WBCS) was developed. WBCS robustly predicted mortality (OR = 2.821; CI: 2.037–3.906; p < 0.001) in the investigated population. Cumulative risk of death according to WBCS (ranging from 0 to 3 points) was as follows: 0 points—10.9%, 1 point—23.5%, 2 points—33.1%, 3 points—34.1%. Conclusions: Based on differential blood count, the proposed WBCS is easy to use and can be helpful in predicting mortality among severe COVID-19 patients. Full article

Background/objectives: SARS-CoV-2 antibodies wane after natural infections and vaccinations. COVID-19 booster vaccination enhances the durability and functionality of antibodies against emerging SARS-CoV-2 variants. Data on booster-induced antibody durability in sub-Saharan Africa remain sparse. Comparative analysis of vaccine-induced responses between heterologous and homologous vaccination regimens remains limited. This study evaluated longitudinal RBD-specific IgG responses following homologous and heterologous COVID-19 booster vaccination in previously vaccinated adults. Methods: Adults with prior mRNA or adenoviral-vectored vaccination were boosted with either Pfizer (mRNA) or Janssen (adenoviral-vectored) vaccines. Plasma IgG binding to Wuhan, Delta, and Omicron RBDs was measured pre-booster and at 3, 6, and 9 months. A total of 181 participants were enrolled between November 2022 and October 2023. Results: More than 60% of participants had detectable pre-booster RBD- and N-antigen-specific IgG. Booster vaccination substantially increased Wuhan-specific RBD-IgG at three months, with limited boosting of Delta and Omicron responses. Antibody levels waned to pre-booster concentrations by month nine. Heterologous boosting with a viral-vectored prime followed by Pfizer mRNA significantly enhanced both peak RBD-IgG levels and durability. Conclusions: These longitudinal data provide rare real-world evidence on booster immunogenicity in African adults and demonstrate that heterologous regimens confer a short- to intermediate-term advantage in antibody magnitude compared to a homologous regimen. This benefit was most pronounced within the first six months post-boost. The findings support additional booster dosing to strengthen protection against emerging variants in sub-Saharan Africa. Full article

Human respiratory syncytial virus (RSV) is the predominant etiological agent responsible for lower respiratory tract infections in young children. Recurrent infections throughout an individual’s lifespan can lead to significant morbidity, particularly in the elderly and in adults, influencing the trends of hospitalization rates. Consequently, it is imperative to develop technologies that can sanitize environments from this pathogen while being compatible with human presence. Structure Resonant Energy Transfer (SRET) is the scientific principle underlying a sanitization technology that has demonstrated efficacy against several enveloped viruses, including SARS-CoV-2 and Influenza A viruses. SRET employs specific frequencies of electromagnetic waves to effectively disrupt the structural integrity of viral envelopes through dipole coupling. This disruption leads to the inactivation of the virus, rendering it non-infectious. The objective of this study is to analyse the effect of a specific SRET sanitization method on RSV. The sanitization test was conducted in aerosol form within a BSL-3 laboratory, exploring the frequency band from 8 to 16 GHz. An optimal sub-band was identified, giving an inactivation efficiency up to 99.5%. In conclusion, it has been demonstrated that the microwave non-thermal sanitization method is effective against RSV. These results confirm its potential as a viable approach for environmental decontamination. Full article

The neuroinvasive and neurotropic character of coronaviruses is a likely reason for neurological complications which may occur during acute COVID illness and sometimes persist or newly emerge in the post-acute phase. Terminology and temporal classification remain heterogeneous. A retrospective case series was conducted in a single center (Department of Neurology, Bielański Hospital, Warsaw, Poland). Medical records from March 2020 to December 2023 were screened. Inclusion criteria: (1) confirmed SARS-CoV-2 infection (polymerase chain reaction or antigen test and radiological findings), (2) new neurological syndrome within acute, post-acute, or post-COVID interval, and (3) diagnostic documentation. Exclusion criteria: alternative established etiology fully explaining the neurological condition. Six cases were selected for detailed analysis due to diagnostic completeness as well as etiological and temporal diversity. Cases included: (1) persistent neurocognitive and sensory symptoms (post-COVID), (2) acute ischemic stroke with internal carotid artery dissection during severe COVID-19, (3) cytotoxic lesion of the corpus callosum (CLOCC) during acute COVID-19, (4) Guillain–Barré syndrome (post-acute), (5) longitudinally extensive transverse myelitis (post-acute), and (6) delayed autoimmune cerebral vasculitis (post-COVID). Neurological presentations ranged from mild persistent symptoms to fatal outcome. Neurological complications span inflammatory, vascular, and autoimmune mechanisms across distinct temporal phases of SARS-CoV-2 infection. Precise temporal classification and systematic diagnostic protocols are essential. Prospective longitudinal studies integrating biomarkers and standardized neuroimaging are required. Full article

Background and Objectives: Osteonecrosis of the jaw (ONJ) occurring after infection with SARS-CoV-2 has emerged as an increasingly reported complication in the post-COVID-19 era. Post-COVID-19 osteonecrosis of the jaw (PC-ONJ) has been described in association with both COVID-19-associated mucormycosis (CAM) and non-fungal phenotypes. This narrative review aims to synthesize and critically analyze the available evidence regarding terminology and classification, epidemiology and risk factors, pathophysiological mechanisms, clinical and imaging characteristics, diagnostic challenges, and management strategies relevant to oral and maxillofacial surgery practice. Materials and Methods: An extensive literature search was conducted in the PubMed/MEDLINE, Scopus, Web of Science, ScienceDirect, and Google Scholar databases. The search targeted peer-reviewed publications published between 2020 and 2025, reflecting the post-pandemic emergence of this clinical spectrum. Original studies, systematic and narrative reviews, multicenter case series, consensus guidelines, and well-documented case reports were considered. Results: Available data, largely derived from case reports and small series, demonstrate a predominance of maxillary involvement and frequent association with diabetes mellitus and systemic corticosteroid therapy. Proposed mechanisms include COVID-19-associated endothelial dysfunction, microvascular thrombosis, immune dysregulation, metabolic imbalance, and treatment-related effects. Clinically, patients may present with persistent orofacial pain, tooth mobility, exposed or probeable bone, and frequent sinonasal extension, with symptoms sometimes preceding bone exposure. Diagnostic challenges arise from the overlap with medication-related osteonecrosis of the jaw (MRONJ), osteoradionecrosis (ORN), and chronic osteomyelitis. Imaging is essential for assessing disease extent but remains insufficient for etiologic differentiation, making histopathological examination and targeted microbiological investigations necessary, particularly to exclude invasive fungal infection. Conclusions: Management must be etiology-driven. CAM requires urgent antifungal therapy combined with surgical debridement, whereas non-fungal forms are generally managed with conservative surgery and appropriate antimicrobial stewardship. Standardized diagnostic criteria and prospective multicenter studies are needed to reduce nosological ambiguity and optimize clinical decision-making in this emerging post-viral condition. Full article

Background: Severe lung compromise from COVID-19, ARDS, and recently AH3N2 can progress to life-threatening hypoxia. Past experience led to standardized protocols that assumed similarity to SARS-CoV. Methods: COVID-19 pathophysiology and histopathological lung biopsy photomicrographs are analyzed. Results: Pneumolysis is defined as progressive alveolar–capillary destruction resulting from SARS-CoV-2 attack on pneumocytes. In the final stages preceding pneumolysis, molecular mechanisms in the lungs include apoptosis in alveolar epithelial type I and II cells, compromising alveolar regeneration, and necrosis, resulting in leakage of intracellular contents and amplifying inflammation. Pyroptosis, driven by inflammasome activity, further disrupts alveolar integrity in ARDS. Histopathological findings include Masson bodies, alveolar-coating cells with nuclear atypia, reactive pneumocytes and reparative fibrosis, intra-alveolar hemorrhage, moderate inflammatory infiltrates and abscesses, microthrombi, hyaline membrane remnants, and emphysema. The three theoretical pathophysiological stages of progressive hypoxemia (silent hypoxemia, gasping, and death zone) are shown. Conclusions: Silent hypoxemia rapidly progresses to critical hypoxemia. This progression results from progressive pneumolysis, inflammation, immune overexpression, autoimmunity, and HAPE-type edema, leading to acute pulmonary insufficiency. Long-lasting COVID-19 can result in fibrosis and, as a compensatory mechanism, polierythrocythemia. The proposed treatment (based on tolerance to hypoxia and the hemoglobin factor) includes prompt oxygen administration, control of inflammatory and immune responses, antibiotics, rehydration, erythropoietin and platelet aggregation inhibitors. Full article

Africa reported lower COVID-19-related morbidity and mortality compared to other continents, despite widespread SARS-CoV-2 transmission and limited vaccine access. Proposed immunological explanations include potential pre-existing immunity such as cross-reactive humoral or cellular responses from earlier coronavirus exposures. However, functional immune responses to SARS-CoV-2 in African populations remain poorly characterized. To address this gap, we assessed post-pandemic neutralizing antibody responses against the SARS-CoV-2 D614G variant. We analyzed plasma samples from 989 participants in a cross-sectional survey in Ghana’s Eastern and Greater Accra regions. A live virus neutralization assay using Vero E6 TMPRSS2 cells was employed to quantify SARS-CoV-2 D614G-specific neutralizing antibodies. Responses were assessed across collected demographic data. Urban participants exhibited higher median neutralizing antibody titers than rural counterparts, in both vaccinated and unvaccinated groups (p < 0.0001). Among unvaccinated individuals, median neutralizing antibody titers were comparable across age groups in urban settings. Vaccinated individuals showed elevated median titers across all age groups, with urban residents demonstrating stronger responses. Significant sex-based differences in neutralizing titres were also identified. Our findings reveal marked disparities in functional antibody responses between urban and rural populations, likely shaped by differences in SARS-CoV-2 exposure and vaccination. Continued surveillance and immunological profiling remain key for informing vaccine strategies and future pandemic preparedness. Full article

Background: MSCs possess strong immunoregulatory properties and play a central role in maintaining immune homeostasis by limiting inflammatory responses. Their function is highly plastic and influenced by environmental cues, including viral signals. How SARS-CoV-2-derived antigens affect MSC immunoregulation remains incompletely understood. This study aimed to investigate the impact of SARS-CoV-2 peptides on MSC-mediated immune modulation of T-cells. Methods: MSCs were stimulated directly with SARS-CoV-2 spike protein S peptides or cocultured with SARS-CoV-2 peptide-activated T-cells. TLR4 surface expression and receptor downstream signaling were assessed to evaluate pathway activation. MSC immunoregulatory function was analyzed by measuring suppression of TNF-α and IFN-γ expression and induction of CD4⁺FOXP3⁺ regulatory T-cells. TLR4 inhibition and lipopolysaccharide (LPS) stimulation were used to examine pathway specificity and interaction. Results: SARS-CoV-2 peptides activated TLR4-associated signaling in MSCs, increasing TLR4 expression and NF-κB phosphorylation. Peptide-treated MSCs showed impaired suppression of pro-inflammatory cytokines and reduced induction of regulatory T-cells. TLR4 inhibition prevented these effects. LPS induced similar effects, while combining LPS and peptide stimulation partially restored physiological T-cell cytokine suppression. Conclusions: SARS-CoV-2 peptides modulate MSC immunoregulatory function on T-cells via TLR4-dependent mechanisms. Full article

Background/Objectives: The continuous emergence of immune-evasive SARS-CoV-2 variants underscores the need for adaptable and accessible therapeutics that complement vaccination. Single-domain antibodies (sdAbs) offer advantages in size, stability, and production costs compared to conventional monoclonal antibodies, but their clinical utility is limited by rapid clearance. This study aimed to develop a rabbit-derived sdAb with broad SARS-CoV-2 neutralization capacity and improved pharmacokinetic properties. Methods: A rabbit-derived variable light-chain (VL) sdAb library was constructed and subjected to phage display selection to identify high-affinity binders. Candidate sdAbs were characterized for cross-variant binding and neutralization. The lead sdAb, B3, was fused to the albumin-binding domain (ABD) of the Streptococcus zooepidemicus Zag protein to enhance in vivo half-life. Expression, albumin-binding capacity, and in vitro neutralization were assessed, followed by biodistribution studies in mice. Results: The selected sdAb, B3, showed strong binding and cross-variant neutralization against multiple SARS-CoV-2 lineages, including Delta and Omicron. Fusion to ABD(Zag) preserved neutralization potency, increased expression yields ~5-fold, and enabled cross-species albumin binding. In vivo, B3-ABD(Zag) exhibited markedly extended blood retention, showing a 21.2-fold increase at 24 h post-injection (5.30 vs. 0.25% I.A./g), and reduced renal uptake by 40% compared with unmodified B3. Conclusions: Rabbit-derived VL sdAbs fused to ABD(Zag) provide a promising platform for next-generation SARS-CoV-2 biologics. The enhanced pharmacokinetic profile of B3-ABD(Zag) supports its potential as a scalable therapeutic modality and highlights the broader utility of this approach for future emerging infectious threats. Full article

Probiotics are widely used to support host health by modulating microbial communities and immune–metabolic homeostasis. Such interventions may be particularly relevant in long COVID syndrome, a condition characterized by persistent symptoms, low-grade inflammation, and microbiota alterations following SARS-CoV-2 infection. This study investigated the effects of a multi-strain probiotic on gut microbiota composition and predicted functional potential and biochemical parameters in individuals with long COVID and convalescent participants. Healthy individuals were included as reference controls. In an interventional study, 34 participants received a 12-week probiotic formulation containing Saccharomyces boulardii, Lacticaseibacillus rhamnosus GG, and two Lactiplantibacillus plantarum strains, while 40 served as non-supplemented controls. Fecal microbiota, assessed using 16S rRNA sequencing, and biochemical markers were measured at baseline and post-intervention. Probiotic supplementation induced selective compositional changes without significantly altering overall microbial diversity. Effects were more pronounced in long COVID participants and included enrichment of bacteria associated with metabolic and immune regulation, including Adlercreutzia, Coprococcus, and Eubacterium. Functional prediction analysis identified a probiotic-responsive signature in long-COVID-affected individuals, characterized by enrichment of pathways related to energy metabolism and redox balance. These microbial changes were accompanied by a consistent trend toward reduced inflammatory and hepatic markers. Overall, probiotic intervention demonstrated microbiota-status-dependent potential in long COVID recovery. Full article