Norwegian National Unit for Platelet Immunology, Department of Laboratory Medicine, University Hospital of North Norway, Tromsø, Norway.
Department of Research, Østfold Hospital, Grålum, Norway.
J Thromb Haemost. 2021 Jul;19(7):1813-1818. doi: 10.1111/jth.15352. Epub 2021 May 18.
The COVID-19 vaccine from AstraZeneca (AZD1222) is one of several vaccines introduced to provide immunity against SARS-CoV-2. Recently, more than 50 cases have been reported presenting a combination of thrombosis, thrombocytopenia, and remarkably high levels of anti-platelet factor 4 (PF4)/polyanion antibodies post-AZD1222 vaccination. Now linked to the vaccine, the condition is referred to as vaccine-induced immune thrombotic thrombocytopenia. The European Medicines Agency still recommends vaccination with AZD1222, but several European countries have temporally paused and/or restricted its use because of the perceived risk of this severe side effect. Because there is no description of PF4/polyanion antibody testing in the clinical trials, knowledge about the prevalence of such antibodies in a vaccinated cohort is needed.
To investigate prevalence of thrombocytopenia and anti-PF4/polyanion antibodies in a population recently vaccinated with AZD1222.
PATIENTS/METHODS: Four hundred and ninety-two health care workers recently vaccinated with the first dose of AZD1222 were recruited from two hospitals in Norway. Study individuals were screened for thrombocytopenia and the presence of anti-PF4/polyanion antibodies with a PF4/PVS immunoassay. Side effects after vaccination were registered.
The majority of study participants had normal platelet counts and negative immunoassay. Anti-PF4/polyanion antibodies without platelet activating properties were only detected in six individuals (optical density ≥0.4, range 0.58-1.16), all with normal platelet counts. No subjects had severe thrombocytopenia.
We found low prevalence of both thrombocytopenia and antibodies to PF4/polyanion-complexes among Norwegian health care workers after vaccination with AZD1222.
阿斯利康（AZD1222）的 COVID-19 疫苗是用于提供针对 SARS-CoV-2 免疫的几种疫苗之一。最近，有 50 多例病例报告在接种 AZD1222 后出现血栓形成、血小板减少症和抗血小板因子 4（PF4）/聚阴离子抗体水平显著升高的情况。现在，这种情况与疫苗相关联，被称为疫苗诱导的免疫性血栓性血小板减少症。欧洲药品管理局仍建议接种 AZD1222 疫苗，但由于担心这种严重副作用的风险，一些欧洲国家已暂时暂停和/或限制其使用。由于临床试验中没有描述 PF4/聚阴离子抗体检测，因此需要了解接种疫苗人群中此类抗体的流行情况。
调查最近接种 AZD1222 的人群中血小板减少症和抗 PF4/聚阴离子抗体的流行情况。
患者/方法：从挪威的两家医院招募了 492 名最近接种 AZD1222 第一剂的医护人员。研究对象通过 PF4/PVS 免疫测定法筛查血小板减少症和抗 PF4/聚阴离子抗体的存在。接种疫苗后的副作用也进行了登记。
大多数研究参与者的血小板计数正常，免疫测定结果为阴性。仅在 6 名个体中检测到无血小板激活特性的抗 PF4/聚阴离子抗体（光密度≥0.4，范围 0.58-1.16），且所有个体的血小板计数均正常。没有受试者出现严重血小板减少症。
我们发现，在挪威医护人员接种 AZD1222 后，血小板减少症和抗 PF4/聚阴离子复合物抗体的发生率均较低。
