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Vector-based SARS-CoV-2 vaccines have been associated with vaccine- induced thrombosis with thrombocytopenia syndrome (VITT/TTS), but the causative factors are still unresolved. We comprehensively analyzed the ChAdOx1 nCoV-19 (AstraZeneca) and Ad26.COV2.S (Johnson and Johnson) vaccines. ChAdOx1 nCoV-19 contains significant amounts of host cell protein impurities, including functionally active proteasomes, and adenoviral proteins. A much smaller amount of impurities was found in Ad26.COV2.S. Platelet factor 4 formed complexes with ChAdOx1 nCoV-19 constituents, but not with purified virions from ChAdOx1 nCoV-19 or with Ad26.COV2.S. Vascular hyperpermeability was induced by ChAdOx nCoV-19 but not by Ad26.COV2.S. These differences in impurities together with EDTAinduced capillary leakage might contribute to the higher incidence rate of VITT associated with ChAdOx1 nCoV-19 compared to Ad26.COV2.S.
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http://dx.doi.org/10.3324/haematol.2021.280154 | DOI Listing |
Allergol Immunopathol (Madr)
September 2025
Faculty of Medicine, University of Prishtina, University Clinical Center of Kosovo, Prishtina, Republic of Kosovo.
Objective: The aim of this study was to assess the association between allergic reactions after COVID-19 vaccination and the history of high-risk allergy, individual predisposing factors such as age and gender, and COVID-19 vaccine type.
Materials And Methods: This retrospective cohort study included 234 adult patients (18 years old and above) who underwent a COVID-19 vaccine allergy test up until February 2023 in a Clinic of Allergy and Clinical Immunology in the University Clinical Center of Kosovo. All patients suspected of allergy underwent skin testing: SPT (skin prick test) and IDT (intradermal test) using either an mRNA (ribonucleic messenger acid) vaccine (BNT162b2, Pfizer-BioNTech) and/or an adenoviral vector vaccine (AZD1222, AstraZeneca).
Indian J Nephrol
July 2024
Department of Pathology, Government Medical College Srinagar, Jammu Kashmir, India.
We report an unusual glomerulopathy with nephrotic syndrome and acute kidney injury almost two weeks after the second injection of SARS CoV-2 vaccine covishield, ChAdOx1-nCoV-19 in a 75-year-old healthy man. Kidney biopsy revealed segmental stage 1 membranous glomerulopathy and collapsing focal segmental glomerulosclerosis pattern with immune complexes on IF. Electron microscopy (EM) revealed aggregates of spherular microparticles along glomerular capillary walls.
View Article and Find Full Text PDFCureus
July 2025
Department of General Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, IND.
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare autoimmune condition characterized by necrotizing inflammation of small- to medium-sized vessels. While various environmental triggers have been implicated, the role of the COVID-19 vaccine as a possible trigger is still being studied. We describe the case of a 21-year-old female patient who developed systemic inflammatory symptoms within 24 hours of receiving her second dose of the Covishield (ChAdOx1 nCoV-19) COVID-19 vaccine.
View Article and Find Full Text PDFSci Immunol
August 2025
Translational Gastroenterology and Liver Unit, Nuffield Department of Medicine - Experimental Medicine, University of Oxford, Oxford, UK.
Adenoviral (Ad) vectors and mRNA vaccines exhibit distinct patterns of immune responses and reactogenicity, but underpinning mechanisms remain unclear. We longitudinally compared homologous ChAdOx1 nCoV-19 and BNT162b2 vaccination, focusing on cytokine-responsive innate-like lymphocytes-mucosal-associated invariant T (MAIT) cells and Vδ2 γδ T cells-which sense and tune innate-adaptive cross-talk. Ad priming elicited robust type I interferon (IFN)-mediated innate-like T cell activation, augmenting T cell responses (innate-to-adaptive signaling), which was dampened at boost by antivector immunity.
View Article and Find Full Text PDFVaccine
August 2025
Department of Medical Microbiology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia. Electronic address:
During the COVID-19 pandemic, Malaysia adopted heterologous vaccine booster strategies using BNT162b2 (Pfizer), CoronaVac (Sinovac) and ChAdOx1 nCoV-19 (AstraZeneca) due to vaccine shortages. However, longitudinal data on immune durability and breakthrough infections, especially in immunocompromised groups, remain limited. This study evaluates humoral response in healthy individuals after primary vaccine series and booster dose, and assesses long-term hybrid immunity up to two years post-booster in both healthy individuals and immunocompromised kidney transplant recipients (KTRs).
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