ABSTRACT
Introduction: In March 2021, a signal for embolic and thrombotic events with Vaxzevria (COVID-19 Vaccine AstraZeneca) was raised in Austria and Germany, and on 7 April 2021, the European Pharmacovigilance Risk Assessment Committee (PRAC) concluded that a causal relationship between Vaxzevria and thrombosis combined to thrombocytopenia (TTS) was at least a reasonable possibility [1]. TTS mechanism is close to heparin-induced thrombocytopenia [2,3]. We report two Luxembourg cases of TTS that occurred one before and one after this confirmed signal. Results: The first case is a 74-year-old woman, with no medical history, who received her first dose of Vaxzevria in March 2021. Fourteen days later, she was hospitalised for sudden loss of consciousness. On admission she had thrombocytopenia (18 G/L), D-Dimers >20 000 ng/mL, antithrombin III 79%, fibrinogen 0.69 g/dL. Brain CT scan showed cerebral and meningeal haemorrhages. She died three days later. Autopsy confirmed multiple intracranial haemorrhages and showed right transverse sinus organised thrombosis. Post-mortem analysis revealed positive heparin-Platelet Factor 4 (PF4) antibodies (HIPA and PIPA). The second case is a 31-year-old man with medical history of splenic infarction in 2017 during mononucleosis. He received his first dose of Vaxzevria in June 2021, and 12 days later was admitted for right lower limb and lumbar pain with severe thrombocytopenia (28 G/L), low fibrinogen and elevated D-Dimers. Angiography showed sub-occlusive cruoric impactions of the left carotid bifurcation, the sub-renal abdominal aorta and the right common femoral artery. PF4 antibody initially negative (Zymutest Hyphen) were positive with IMMUCOR technique. Management included clots removal, intravenous immunoglobulins started for 3 days and anticoagulation with sodium danaparoid. The patient recovered within one month without sequelae. Discussion/Conclusion: The quick communication about TTS signal and the rapid identification of its mechanism both allowed, as reported here for the second patient, adapted management (prohibiting heparin), with full recovery.