Section of Clinical Biochemistry, University of Verona, Verona, Italy.
Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, New South Wales, Australia.
Semin Thromb Hemost. 2022 Feb;48(1):8-14. doi: 10.1055/s-0041-1736168. Epub 2021 Oct 25.
Despite the huge efforts globally underway for preventing or limiting the spread of severe acute respiratory coronavirus disease 2 (SARS-CoV-2), the coronavirus disease 2019 (COVID-19) pandemic outbreak appears still virtually unstoppable. As for many other infectious diseases, COVID-19 vaccination has now become crucial for limiting viral spread, especially for averting hospitalizations, need for intensive care, and fatal outcome. Nonetheless, as for other vaccines, COVID-19 vaccination is not completely free from side effects. Among the adverse events that have been reported after receiving COVID-19 vaccination, special emphasis has been given to an unexpected number of thrombocytopenic episodes with or without thrombotic complications, especially in recipients of adenovirus-based COVID-19 vaccines. Along with a specific clinical presentation, encompassing "atypical" thrombosis (especially cerebral venous [sinus] thrombosis, CVT) more prevalent in young female subjects, this new syndrome called vaccine-induced thrombocytopenia and thrombosis (VITT) is characterized by, and thereby diagnosed for, the presence of three paradigmatic laboratory abnormalities, i.e., low platelet count (<150 × 10/L), elevated plasma D-dimer levels (>0.5 mg/L), accompanied by a positive test for anti-PF4 (platelet factor 4) antibodies assayed with ELISA (enzyme-linked immunosorbent assay) techniques. Timely identification of these important abnormalities by both clinicians and laboratory professional is essential for early diagnosis and management of VITT, since the outcome of this condition may be fatal in half or even more of effected patients with severe disease. Therefore, this narrative review aims to review here the epidemiology, pathogenesis, clinical, and laboratory characteristics of VITT and other COVID-19 vaccine-associated thrombocytopenias.
尽管全球正在努力预防或限制严重急性呼吸综合征冠状病毒 2 型（SARS-CoV-2）的传播，但 2019 年冠状病毒病（COVID-19）大流行似乎仍几乎无法阻止。与许多其他传染病一样，COVID-19 疫苗接种现在对于限制病毒传播至关重要，特别是可以避免住院、需要重症监护和致命结果。然而，与其他疫苗一样，COVID-19 疫苗并非完全没有副作用。在接种 COVID-19 疫苗后报告的不良反应中，特别强调了数量意外的血小板减少症发作伴有或不伴有血栓并发症，特别是在接受腺病毒 COVID-19 疫苗的接种者中。除了具有“非典型”血栓形成（特别是脑静脉[窦]血栓形成，CVT）的特定临床表现，在年轻女性患者中更为常见外，这种称为疫苗诱导的血小板减少和血栓形成（VITT）的新综合征的特征是并通过存在三种典型的实验室异常来诊断，即血小板计数低（<150×10/L）、血浆 D-二聚体水平升高（>0.5mg/L），并伴有 ELISA（酶联免疫吸附测定）技术检测到的抗 PF4（血小板因子 4）抗体阳性。临床医生和实验室专业人员及时识别这些重要异常对于 VITT 的早期诊断和管理至关重要，因为这种情况的结果在一半或更多患有严重疾病的受影响患者中可能是致命的。因此，本叙述性评论旨在回顾 VITT 及其他 COVID-19 疫苗相关血小板减少症的流行病学、发病机制、临床和实验室特征。
