ArticleThe New England journal of medicine2021
Thrombotic Thrombocytopenia after ChAdOx1 nCov-19 Vaccination.
Article in The New England journal of medicine, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1,330 papers, 5 of them syntheses that pooled it.
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1,330 citing papers in PubMed, 5 syntheses or guidelines pooled it, 2,257 citations in OpenAlex.
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- Risk of venous thromboembolism after SARS-CoV-2 vaccination-Evidence from genome-wide association study and population-based observational study.British journal of clinical pharmacology · 2026Observational
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- Rhino-Orbital Mucormycosis Following COVID-19 Viral Vector Vaccination in an Immunocompetent Patient.Journal of fungi (Basel, Switzerland) · 2026Article
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- The Effect of COVID-19 Vaccines on Chronic Inflammatory Remodeling in NSTEMI Patients: A Galectin-3-Based Single-Center Study.Journal of clinical medicine · 2026Article
- Platelet FcγRIIA is dispensable for hemostasis and arterial thrombosis in the absence of FcγRIIA-specific extracellular stimuli.Research and practice in thrombosis and haemostasis · 2026Article
- Lack of association between vaccine-induced immune thrombocytopenia and thrombosis and HLA loci in a large cohort.British journal of haematology · 2026Article
- Xenosialylation as immunological chimerism: a host-centered unifying model for viral and post-vaccination immune complications.European cytokine network · 2026Review
1,270 more citing papers are in PubMed but not listed here.
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Authors and funding
6 authors at 1 institution in 3 countries.
Funding
Abstract
backgroundSeveral cases of unusual thrombotic events and thrombocytopenia have developed after vaccination with the recombinant adenoviral vector encoding the spike protein antigen of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (ChAdOx1 nCov-19, AstraZeneca). More data were needed on the pathogenesis of this unusual clotting disorder.
methodsWe assessed the clinical and laboratory features of 11 patients in Germany and Austria in whom thrombosis or thrombocytopenia had developed after vaccination with ChAdOx1 nCov-19. We used a standard enzyme-linked immunosorbent assay to detect platelet factor 4 (PF4)-heparin antibodies and a modified (PF4-enhanced) platelet-activation test to detect platelet-activating antibodies under various reaction conditions. Included in this testing were samples from patients who had blood samples referred for investigation of vaccine-associated thrombotic events, with 28 testing positive on a screening PF4-heparin immunoassay.
resultsOf the 11 original patients, 9 were women, with a median age of 36 years (range, 22 to 49). Beginning 5 to 16 days after vaccination, the patients presented with one or more thrombotic events, with the exception of 1 patient, who presented with fatal intracranial hemorrhage. Of the patients with one or more thrombotic events, 9 had cerebral venous thrombosis, 3 had splanchnic-vein thrombosis, 3 had pulmonary embolism, and 4 had other thromboses; of these patients, 6 died. Five patients had disseminated intravascular coagulation. None of the patients had received heparin before symptom onset. All 28 patients who tested positive for antibodies against PF4-heparin tested positive on the platelet-activation assay in the presence of PF4 independent of heparin. Platelet activation was inhibited by high levels of heparin, Fc receptor-blocking monoclonal antibody, and immune globulin (10 mg per milliliter). Additional studies with PF4 or PF4-heparin affinity purified antibodies in 2 patients confirmed PF4-dependent platelet activation.
conclusionsVaccination with ChAdOx1 nCov-19 can result in the rare development of immune thrombotic thrombocytopenia mediated by platelet-activating antibodies against PF4, which clinically mimics autoimmune heparin-induced thrombocytopenia. (Funded by the German Research Foundation.).
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