Uzun Günalp, Ringelmann Theresa, Hammer Stefanie, Zlamal Jan, Luz Beate, Wolf Marc E, Henkes Hans, Bakchoul Tamam, Althaus Karina
Centre for Clinical Transfusion Medicine Tuebingen, 72076 Tuebingen, Germany.
Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tuebingen, University Hospital of Tuebingen, 72076 Tuebingen, Germany.
J Clin Med. 2024 Sep 14;13(18):5462. doi: 10.3390/jcm13185462.
Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but severe complication following vaccination with adenovirus vector-based COVID-19 vaccines. Antibodies directed against platelet factor 4 (PF4) are thought to be responsible for platelet activation and subsequent thromboembolic events in these patients. Since a single vaccination does not lead to sufficient immunization, subsequent vaccinations against COVID-19 have been recommended. However, concerns exist regarding the possible development of a new thromboembolic episode after subsequent vaccinations in VITT patients. We prospectively analyzed follow-up data from four VITT patients (three women and one man; median age, 44 years [range, 22 to 62 years]) who subsequently received additional COVID-19 vaccines. Platelet counts, anti-PF4/heparin antibody level measurements, and a functional platelet activation assay were performed at each follow-up visit. Additionally, we conducted a literature review and summarized similar reports on the outcome of subsequent vaccinations in patients with VITT. The patients had developed thrombocytopenia and thrombosis 4 to 17 days after the first vaccination with ChAdOx1 nCoV-19. The optical densities (ODs) of anti-PF4/heparin antibodies decreased with time, and three out of four patients tested negative within 4 months. One patient remained positive even after 10 months post first vaccination. All four patients received an mRNA-based vaccine as a second vaccination against SARS-CoV-2. No significant drop in platelet count or new thromboembolic complications were observed during follow-up. We identified seven publications reporting subsequent COVID-19 vaccination in VITT patients. None of the patients developed thrombocytopenia or thrombosis after the subsequent vaccination. Subsequent vaccination with an mRNA vaccine appears to be safe in VITT patients.
疫苗诱导的免疫性血栓性血小板减少症（VITT）是接种基于腺病毒载体的COVID-19疫苗后出现的一种罕见但严重的并发症。针对血小板因子4（PF4）的抗体被认为是这些患者血小板活化及随后血栓栓塞事件的原因。由于单次接种不能产生足够的免疫效果，因此建议后续接种COVID-19疫苗。然而，对于VITT患者后续接种疫苗后可能发生新的血栓栓塞事件存在担忧。我们前瞻性分析了4例VITT患者（3名女性和1名男性；中位年龄44岁[范围22至62岁]）的随访数据，这些患者随后接种了额外的COVID-19疫苗。每次随访时均进行血小板计数、抗PF4/肝素抗体水平检测及功能性血小板活化分析。此外，我们进行了文献综述并总结了关于VITT患者后续接种疫苗结果的类似报告。这些患者在首次接种ChAdOx1 nCoV-19疫苗后4至17天出现血小板减少和血栓形成。抗PF4/肝素抗体的光密度（OD）随时间下降，4名患者中有3名在4个月内检测为阴性。1例患者在首次接种后甚至10个月仍为阳性。所有4例患者均接受了基于mRNA的疫苗作为第二次针对SARS-CoV-2的疫苗接种。随访期间未观察到血小板计数显著下降或新的血栓栓塞并发症。我们确定了7篇报告VITT患者后续接种COVID-19疫苗的文献。后续接种疫苗后，所有患者均未出现血小板减少或血栓形成。对于VITT患者，后续接种mRNA疫苗似乎是安全的。
