Search Results (258)

Vilobelimab, a first-in-class, human–mouse chimeric immunoglobulin G4 (IgG4) kappa monoclonal antibody, targets human complement component 5a (C5a) in plasma. Unlike upstream complement inhibitors, vilobelimab does not inhibit the generation of the membrane attack complex (C5b-9), necessary to mitigate certain infections. C5a is a strong anaphylatoxin and chemotactic agent that plays an essential role in both innate and adaptive immunity. Elevated levels of C5a have been associated with pathologic processes, including sepsis and inflammatory respiratory disorders such as acute respiratory distress syndrome (ARDS). Blocking C5a with vilobelimab has shown therapeutic promise. A randomized, multicenter placebo-controlled Phase III study of vilobelimab in patients with severe COVID-19 (PANAMO) found that patients treated with vilobelimab had a significantly lower risk of death by day 28 and 60. Based on this study, the United States Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for Gohibic^® (vilobelimab) injection for the treatment of COVID-19 in hospitalized adults when initiated within 48 h of receiving invasive mechanical ventilation (IMV) or extracorporeal membrane oxygenation (ECMO). In January 2025, the European Commission (EC) granted marketing authorization for Gohibic^® (vilobelimab) for the treatment of adult patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced ARDS who are receiving systemic corticosteroids as part of standard of care and receiving IMV with or without ECMO. Herein, we review the mechanism of action of vilobelimab in selectively inhibiting C5a-induced inflammation, outlining its bench-to-bedside development from the fundamental biology of the complement system and preclinical evidence through to the clinical data demonstrating its life-saving potential in the management of COVID-19–induced ARDS. Full article

Long COVID (LC), also known as post-acute sequelae of COVID-19 infection (PASC), is a heterogeneous and debilitating chronic disease that currently affects 10 to 20 million people in the U.S. and over 420 million people globally. With no approved treatments, the long-term global health and economic impact of chronic LC remains high and growing. LC affects children, adolescents, and healthy adults and is characterized by over 200 diverse symptoms that persist for months to years after the acute COVID-19 infection is resolved. These symptoms target twelve major organ systems, causing dyspnea, vascular damage, cognitive impairments (“brain fog”), physical and mental fatigue, anxiety, and depression. This heterogeneity of LC symptoms, along with the lack of specific biomarkers and diagnostic tests, presents a significant challenge to the development of LC treatments. While several biological abnormalities have emerged as potential drivers of LC, a causative factor in a large subset of patients with LC, involves reservoirs of virus and/or viral RNA (vRNA) that persist months to years in multiple organs driving chronic inflammation, respiratory, muscular, cognitive, and cardiovascular damages, and provide continuous viral antigenic stimuli that overstimulate and exhaust CD4⁺ and CD8⁺ T cells. In this review, we (i) shed light on persisting virus and vRNA reservoirs detected, either directly (from biopsy, blood, stool, and autopsy samples) or indirectly through virus-specific B and T cell responses, in patients with LC and their association with the chronic symptomatology of LC; (ii) explore potential mechanisms of inflammation, immune evasion, and immune overstimulation in LC; (iii) review animal models of virus reservoirs in LC; (iv) discuss potential T cell immunotherapeutic strategies to reduce or eliminate persistent virus reservoirs, which would mitigate chronic inflammation and alleviate symptom severity in patients with LC. Full article

Background: The COVID-19 pandemic provided a unique opportunity to evaluate how the human immune system responded to a novel pathogen and to determine whether immune responses initiated through natural infection differ from those elicited by vaccination against the same antigen. Here, we provide a comprehensive analysis of SARS-CoV-2 Spike (S-antigen)-reactive memory B cells (B_mem) elicited in previously immunologically naïve subjects following their first infection with the original Wuhan-Hu-1 (WH1)-like strain or their initial COVID-19 mRNA prime-boost regimen encoding the same WH1-S-antigen. In particular, we tested the hypothesis that the primary encounter of SARS-CoV-2 S-antigen in lung mucosal tissues during infection vs. intramuscular COVID-19 mRNA injection would elicit different B_mem responses. Methods: Cryopreserved peripheral blood mononuclear cell (PBMC) samples collected following primary infection with the WH1 strain or completion of the initial prime-boost vaccination regimen were tested in ImmunoSpot^® assays to assess the frequency, Ig class/subclass usage, and cross-reactivity of the S-antigen-reactive B_mem compartment; pre-pandemic blood draws served as naïve controls. Results: The B_mem repertoires generated post-infection vs. post-vaccination were found to be quite similar but with some subtle differences. In both cases, the prevalent induction of IgG1-expressing B_mem in similar frequencies was seen, ~30% of which targeted the receptor binding domain (RBD) of the WH1-S-antigen. Also, the extent of cross-reactivity with the future Omicron (BA.1) RBD was found to be similar for both cohorts. However, IgA⁺ B_mem were preferentially induced after infection, while IgG4⁺ B_mem were detected only after vaccination. Conclusions: B_mem elicited in naïve human subjects following SARS-CoV-2 infection or after WH1-S encoding mRNA vaccination were only subtly different, although the relevance of these differences as it relates to immune protection warrants further investigation. Our findings serve to illustrate the usefulness and feasibility of performing comprehensive monitoring of antigen-specific B cell memory in larger cohorts using the ImmunoSpot^® technique. Full article

Influenza is a serious and global health issue, and it is a major cause of morbidity, fatality, and economic loss every year. Seasonal vaccines exist but are not very effective due to strain mismatches, delays in production, and antigenic drift. This comprehensive overview discusses the current situation of influenza vaccination, including the numerous types of vaccines—inactivated, live attenuated, and recombinant vaccines—and their effectiveness, efficacy, and associated challenges. It highlights the effects of the COVID-19 pandemic on the trends of influenza vaccination and the level to which innovation should be practiced. In the future universal influenza vaccines will be developed that target conserved viral antigens to provide long-term protection to people. In the meantime, novel vaccine delivery platforms, such as mRNA technology, virus-like particle (VLP), and nanoparticle-based systems, and less cumbersome and invasive administration routes, as well as immune responses are also under development to increase access and production capacity. Collectively, these innovations have the potential to not only reduce the global influenza epidemic but also to change the way influenza is prevented and prepare the world for a pandemic. Full article

Vaccines played a crucial role in the COVID-19 pandemic, but their long-term biological effects and efficacy in vulnerable populations remain under intensive investigation. This study assessed clinical outcomes, comorbidities, and systemic biomarker and proteomic profiles in 366 multimorbid patients, stratified into four groups based on SARS-CoV-2 infection and vaccination status (COV+ vac+, COV+ vac−, COV− vac+, COV− vac−). Clinical and laboratory data, including comorbidities and relevant biomarkers, were collected. Proteomic analysis using mass spectrometry was performed to identify molecular changes associated with infection and vaccination. Statistical analyses examined associations between clinical status, biomarkers, and patient outcomes. As most participants received mRNA-based vaccines, the results primarily reflect responses to spike protein-expressing platforms. Biomarkers of cardiac and renal stress—namely proBNP and carbamide—were elevated in vaccinated individuals. Five deaths occurred in the COV+ vac+ group and two in the COV+ vac− group, most of which were attributed to exacerbations of pre-existing chronic diseases rather than to COVID-19 pneumonia. Protection against breakthrough infections waned over time, particularly beyond 200 days post-vaccination. Mass spectrometry identified proteins such as actin, fibrinogen chains, and SAA2 as potential diagnostic targets. Although the cross-sectional observational design limits the ability to draw causal inferences, the observed waning immunity and potential systemic alterations in vaccinated multimorbid patients highlight the importance of longitudinal follow-up to guide tailored immunization strategies and post-vaccination monitoring in high-risk groups. Full article

Background/Objectives: DTP3 (diphtheria–tetanus–pertussis vaccine, third dose) coverage is a key indicator of the strength and continuity of routine immunization programs, which demonstrably reduces the burden of infectious diseases globally. This study aims to assess trends in DTP3 vaccination coverage across Asian regions and countries from 2012 to 2023, focusing on changes associated with the COVID-19 pandemic. Methods: DTP3 vaccination data were obtained from official WHO/UNICEF Estimates of National Immunization Coverage (WUENIC) and analyzed using Joinpoint regression to detect statistically significant changes in vaccination trends. Data were grouped by five Asian subregions based on the UN geoscheme (Central, Eastern, Southeastern, Southern, and Western Asia), and trends were weighted using birth cohort sizes. The presence of joinpoints and annual percentage changes (APCs) was calculated, and potential pandemic-related disruptions were contextualized. Results: At the continental level, Asia experienced a modest 0.4% annual increase in DTP3 coverage between 2012 and 2023, with a significant joinpoint detected in 2018. Following this, Southeast Asia’s coverage declined at an annual rate of −4.32% before beginning to recover in 2021, while South Asia showed a similar pattern. Country-level analysis revealed significant heterogeneity, with a comparison between 2019 and 2023 showing profound post-pandemic declines in some nations, such as Lebanon (–21%) and Myanmar (–9.4%), while others, like Iraq and the Philippines, achieved substantial recoveries with coverage increasing by over 6 percentage points. These trends contrasted with persistent declines in fragile states (e.g., Afghanistan, Yemen) and sustained high coverage in others (e.g., Bangladesh, Israel). The pandemic, systemic weaknesses, emerging vaccine hesitancy, and misinformation were identified as key influences. Conclusions: There is progress in DTP3 coverage across Asia. There were pandemic-related disruptions, particularly in regions with fragile health systems. Strategies to address zero-dose and dropout children, improve service continuity, and counter misinformation are essential to meet immunization targets under the Immunization Agenda 2030. Full article

Background: Vaccination is a crucial public health measure to control infectious diseases, including seasonal influenza. Yet, vaccine uptake varies globally due to sociodemographic factors, misinformation, and access disparities. Objectives: The objective of this study was to assess the prevalence and sociodemographic factors associated with vaccination and the main reasons for vaccine hesitancy in Albania. Methods: A cross-sectional study, conducted in Albania in November–December 2021, included a sample of 1302 individuals aged ≥18 years (≈57% females; mean age: 38.3 ± 15.0 years; response rate: ≈87%). A structured questionnaire was administered inquiring about co-vaccination status against seasonal influenza and COVID-19, reasons for not being vaccinated, and sociodemographic characteristics of participants. Binary logistic regression was used to assess the association of co-vaccination status with sociodemographic factors. Results: Overall, about 28% of individuals were co-vaccinated against seasonal influenza and COVID-19 at least with one dose (25% in males vs. 29% in females; 22% among 18–24-year-olds vs. 54% among those aged ≥65 years). Independent positive and significant correlates of being co-vaccinated included older age (OR = 7.0, 95%CI = 3.7–12.9) and a higher educational attainment (OR = 2.3, 95%CI = 1.4–3.6). The main reasons for vaccine hesitancy among non-vaccinated individuals included the belief that vaccines are: harmful (72%), not effective (66%), weaken the immune system (58%), are not safe (56%), and preference to recover naturally (52%). Conclusions: This study evidenced a relatively low co-vaccination rate in Albania with significant sociodemographic disparities, notwithstanding the availability of vaccines and their free-of-charge provision to the overall population. Older age and higher educational attainment were identified as independent positive predictors of co-vaccination uptake, suggesting the need for targeted public health strategies to address vaccine hesitancy, particularly among younger and less-educated population categories. Our findings emphasize the importance of tailored communication campaigns and community-based interventions to improve vaccine coverage and mitigate the impact of infectious diseases in Albania and elsewhere. Full article

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrosing lung disease characterized by chronic inflammation, vascular remodeling, and immune dysregulation. COVID-19, caused by SARS-CoV-2, shares several systemic immunohematologic disturbances with IPF, including cytokine storms, endothelial injury, and prothrombotic states. Unlike general comparisons of viral infections and chronic lung disease, this review offers a focused analysis of the shared hematologic and immunologic mechanisms between COVID-19 and IPF. Our aim is to better understand how SARS-CoV-2 infection may worsen disease progression in IPF and identify converging pathophysiological pathways that may inform clinical management. We conducted a narrative synthesis of the peer-reviewed literature from PubMed, Scopus, and Web of Science, focusing on clinical, experimental, and pathological studies addressing immune and coagulation abnormalities in both COVID-19 and IPF. Both diseases exhibit significant overlap in inflammatory and fibrotic signaling, particularly via the TGF-β, IL-6, and TNF-α pathways. COVID-19 amplifies coagulation disturbances and endothelial dysfunction already present in IPF, promoting microvascular thrombosis and acute exacerbations. Myeloid cell overactivation, impaired lymphocyte responses, and fibroblast proliferation are central to this shared pathophysiology. These synergistic mechanisms may accelerate fibrosis and increase mortality risk in IPF patients infected with SARS-CoV-2. This review proposes an integrative framework for understanding the hematologic and immunologic convergence of COVID-19 and IPF. Such insights are essential for refining therapeutic targets, improving prognostic stratification, and guiding early interventions in this high-risk population. Full article

Background: Mucosal immunity plays a pivotal role in preventing infections with SARS-CoV-2. While COVID-19 mRNA vaccines induce robust systemic immune responses in patients with inflammatory bowel disease (IBD), little is known about their efficacy in the mucosal immune compartment. In this sub-investigation of the ongoing STAR-SIGN study, we present the first analysis of mucosal immunity elicited by XBB.1.5 mRNA vaccines in immunocompromised patients with IBD. Methods: IgG and IgA antibodies targeting the receptor-binding domain of the SARS-CoV-2 JN.1 variant were quantified longitudinally in the saliva of IBD patients using the multiplex immunoassay MultiCoV-Ab. Antibody levels were quantified before and 2–4 weeks after vaccination with XBB.1.5 mRNA vaccines. All patients previously received three doses with original COVID-19 vaccines. Results: Mucosal IgG antibodies were readily induced by XBB.1.5 mRNA vaccines (p = 0.0013 comparing pre- and post-vaccination levels). However, mucosal IgA levels were comparable before and after vaccination (p = 0.8233). Consequently, mucosal IgG and IgA antibody levels correlated only moderately before and after immunization (pre-vaccination: r = 0.5294; p = 0.0239; post-vaccination: r = 0.4863; p = 0.0407). Contrary to a previous report in healthy individuals, vaccination did not induce serum IgA in patients with IBD (p = 0.5841 comparing pre- and post-vaccination levels). These data suggest that COVID-19 mRNA vaccines fail to elicit mucosal IgA in patients with IBD. Conclusions: Since mucosal IgA plays a pivotal role in infection control, the lack of IgA induction indicates that patients lack sufficient protection against SARS-CoV-2 infections which warrants the development of mucosal COVID-19 vaccines. Full article

The COVID-19 pandemic has revealed the profound and lasting impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the nervous system. Beyond acute infection, SARS-CoV-2 acts as a potent immunomodulatory agent, disrupting immune homeostasis and contributing to persistent inflammation, autoimmunity, and neurodegeneration. Long COVID, or post-acute sequelae of SARS-CoV-2 infection (PASC), is characterized by a spectrum of neurological symptoms, including cognitive dysfunction, fatigue, neuropathy, and mood disturbances. These are linked to immune dysregulation involving cytokine imbalance, blood–brain barrier (BBB) disruption, glial activation, and T-cell exhaustion. Key biomarkers such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NFL) correlate with disease severity and chronicity. This narrative review examines the immunopathological mechanisms underpinning the neurological sequelae of long COVID, focusing on neuroinflammation, endothelial dysfunction, and molecular mimicry. We also assess the role of viral variants in shaping neuroimmune outcomes and explore emerging diagnostic and therapeutic strategies, including biomarker-guided and immune-targeted interventions. By delineating how SARS-CoV-2 reshapes neuroimmune interactions, this review aims to support the development of precision-based diagnostics and targeted therapies for long COVID-related neurological dysfunction. Emerging approaches include immune-modulatory agents (e.g., anti-IL-6), neuroprotective drugs, and strategies for repurposing antiviral or anti-inflammatory compounds in neuro-COVID. Given the high prevalence of comorbidities, personalized therapies guided by biomarkers and patient-specific immune profiles may be essential. Advancements in vaccine technologies and targeted biologics may also hold promise for prevention and disease modification. Finally, continued interdisciplinary research is needed to clarify the complex virus–immune–brain axis in long COVID and inform effective clinical management. Full article

Cases of new COVID-19 infection, which manifested in 2019 and caused a global socioeconomic crisis, still continue to be registered worldwide. The high mutational activity of SARS-CoV-2 leads to the emergence of new antigenic variants of the virus, which significantly reduces the effectiveness of COVID-19 vaccines, as well as the sensitivity of diagnostic test systems based on variable viral antigens. These problems may be solved by focusing on highly conserved coronavirus antigens, for example nucleocapsid (N) protein, which is actively expressed by coronavirus-infected cells and serves as a target for the production of virus-specific antibodies and T cell responses. It is known that anti-N antibodies are non-neutralizing, but their protective potential and functional activity are not sufficiently studied. Here, the protective effect of anti-N antibodies was studied in Syrian hamsters passively immunized with polyclonal sera raised to N(B.1) recombinant protein. The animals were infected with 10⁵ or 10⁴ TCID₅₀ of SARS-CoV-2 (B.1, Wuhan or BA.2.86.1.1.18, Omicron) 6 h after serum passive transfer, and protection was assessed by weight loss, clinical manifestation of disease, viral titers in the respiratory tract, as well as by the histopathological evaluation of lung tissues. The functional activity of anti-N(B.1) antibodies was evaluated by complement-dependent cytotoxicity (CDC) and antibody-dependent cytotoxicity (ADCC) assays. The protection of anti-N antibodies was evident only against a lower dose of SARS-CoV-2 (B.1) challenge, whereas almost no protection was revealed against BA.2.86.1.1.18 variant. Anti-N(B.1) monoclonal antibodies were able to stimulate both CDC and ADCC. Thus, anti-N(B.1) antibodies possess protective activity against homologous challenge infection, which is possibly mediated by innate Fc-mediated immune reactions. These data may be informative for the development of N-based broadly protective COVID-19 vaccines. Full article

Cognitive dysfunction represents one of the most persistent and disabling features of Long COVID, yet its molecular underpinnings remain incompletely understood. This narrative review synthesizes current evidence on the pathophysiological mechanisms linking SARS-CoV-2 infection to long-term neurocognitive sequelae. Key processes include persistent neuroinflammation, blood–brain barrier (BBB) disruption, endothelial dysfunction, immune dysregulation, and neuroendocrine imbalance. Microglial activation and cytokine release (e.g., IL-6, TNF-α) promote synaptic dysfunction and neuronal injury, while activation of inflammasomes such as NLRP3 amplifies CNS inflammation. Vascular abnormalities, including microthrombosis and BBB leakage, facilitate the infiltration of peripheral immune cells and neurotoxic mediators. Hypothalamic–pituitary–adrenal axis dysfunction and reduced vagal tone further exacerbate systemic inflammation and autonomic imbalance. Biomarkers such as GFAP, NFL, IL-6, and S100B have been associated with both neuroinflammation and cognitive symptoms. Notably, transcriptomic signatures in Long COVID overlap with those observed in Alzheimer’s disease, highlighting shared pathways involving tau dysregulation, oxidative stress, and glial reactivity. Understanding these mechanisms is critical for identifying at-risk individuals and developing targeted therapeutic strategies. This review underscores the need for longitudinal research and integrative biomarker analysis to elucidate the molecular trajectory of cognitive impairment in Long COVID. Full article

Glucocorticoids (GCs) have revolutionized the treatment of multidisciplinary diseases. Recently, its role in severe infectious diseases has been revisited and discussed since the COVID-19 pandemic. Previous research and discussions have focused more on their anti-inflammatory effects and impact on the immune system, with limited study on other aspects of their action and mechanisms. In recent years, it has been discovered that glucocorticoids can regulate the extracellular matrix by influencing the cellular microenvironment and processes such as fibrosis, thereby exerting regulatory effects on diseases. This article summarizes current research on GC-mediated extracellular matrix (ECM) remodeling. It emphasizes the dual role of the ECM as a therapeutic target and a source of biomarkers, and identifies molecular mechanisms and potential biomarkers for precise glucocorticoid therapy, such as type I collagen (PRO-C1), type III collagen (PRO-C3), fibrillin-C (FBN-C), and type III collagen degradation (C3M). These findings may also contribute to the development of more precise new drugs. Full article

This article summarizes the case of 30-year-old male diagnosed with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and its longitudinal follow-up, which provided a secondary diagnosis of Multiple Sclerosis (MS) eight years later. The most impactful result was his response to rituximab treatment after the systematic failure of prior treatments. Although the expression of endogenous retroviral proteins has been associated with autoimmunity, the patient did not show increased expression of the toxic protein HERV (human endogenous retrovirus)-W ENV, a target of the ongoing clinical trials with temelimab in MS and long COVID-19 cases. However, genome-wide HERV transcriptome analysis by high density microarrays clearly revealed a distinct profile in the patient’s blood supportive of an altered immune system. Limitations of the study include sub-optimal frequency of magnetic resonance imaging to monitor lesion progression, and similarly for reassessment of HERV profiles after rituximab. Overall, the coincidence of HERV alterations and the impactful response to rituximab presents the possibility of additional, more specific, therapeutic targets encoded by other HERV elements yet to be discovered. Full article

The Coronavirus Disease 2019 (COVID-19) pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), disproportionately affects individuals with diabetes mellitus (DM) by exacerbating cardiovascular and renal complications. This increased risk is mediated through immune dysfunction, chronic inflammation, hyperglycemia, dysregulation of renin-angiotensin system dysregulation, endothelial dysfunction, and hypercoagulability. Epidemiological studies indicate a two-fold increased risk of stroke and end-stage renal disease in SARS-CoV-2-infected individuals with diabetes, along with a 60% higher risk of cardiovascular disease. While antidiabetic therapies like sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists show potential protective effects, insulin use in hospitalized patients is linked to higher mortality. Vaccination is crucial in reducing severe COVID-19 outcomes and mitigating post-infection complications, including new-onset diabetes. While concerns exist regarding vaccine-associated nephropathy and thromboembolic events, these risks are thought to be minimal compared to the benefits. As COVID-19 shifts to an endemic phase, the long-term renal and cardiovascular outcomes in patients with DM remain uncertain, highlighting the urgent need for continued research and targeted management strategies. Full article