Background

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a new syndrome associated with the ChAdOx1 nCoV-19 adenoviral vector vaccine against severe acute respiratory syndrome coronavirus 2. Data are lacking on the clinical features of and the prognostic criteria for this disorder.

Methods

We conducted a prospective cohort study involving patients with suspected VITT who presented to hospitals in the United Kingdom between March 22 and June 6, 2021. Data were collected with the use of an anonymized electronic form, and cases were identified as definite or probable VITT according to prespecified criteria. Baseline characteristics and clinicopathological features of the patients, risk factors, treatment, and markers of poor prognosis were determined.

Results

Among 294 patients who were evaluated, we identified 170 definite and 50 probable cases of VITT. All the patients had received the first dose of ChAdOx1 nCoV-19 vaccine and presented 5 to 48 days (median, 14) after vaccination. The age range was 18 to 79 years (median, 48), with no sex preponderance and no identifiable medical risk factors. Overall mortality was 22%. The odds of death increased by a factor of 2.7 (95% confidence interval [CI], 1.4 to 5.2) among patients with cerebral venous sinus thrombosis, by a factor of 1.7 (95% CI, 1.3 to 2.3) for every 50% decrease in the baseline platelet count, by a factor of 1.2 (95% CI, 1.0 to 1.3) for every increase of 10,000 fibrinogen-equivalent units in the baseline d-dimer level, and by a factor of 1.7 (95% CI, 1.1 to 2.5) for every 50% decrease in the baseline fibrinogen level. Multivariate analysis identified the baseline platelet count and the presence of intracranial hemorrhage as being independently associated with death; the observed mortality was 73% among patients with platelet counts below 30,000 per cubic millimeter and intracranial hemorrhage.

Conclusions

The high mortality associated with VITT was highest among patients with a low platelet count and intracranial hemorrhage. Treatment remains uncertain, but identification of prognostic markers may help guide effective management. (Funded by the Oxford University Hospitals NHS Foundation Trust.)

中文翻译：

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疫苗诱导的免疫性血小板减少症和血栓形成的临床特征

背景

疫苗诱导的免疫性血小板减少症和血栓形成 (VITT) 是一种与针对严重急性呼吸综合征冠状病毒 2 的 ChAdOx1 nCoV-19 腺病毒载体疫苗相关的新综合征。缺乏关于这种疾病的临床特征和预后标准的数据。

方法

我们进行了一项前瞻性队列研究，纳入了 2021 年 3 月 22 日至 6 月 6 日期间在英国医院就诊的疑似 VITT 患者。使用匿名电子表格收集数据，并将病例确定为明确或可能的 VITT到预先规定的标准。确定患者的基线特征和临床病理学特征、危险因素、治疗方法和预后不良的标志物。

结果

在接受评估的 294 名患者中，我们确定了 170 例确诊和 50 例可能的 VITT 病例。所有患者均已接种第一剂 ChAdOx1 nCoV-19 疫苗，并在接种疫苗后 5 至 48 天（中位数，14 天）出现。年龄范围为 18 至 79 岁（中位数为 48 岁），没有性别优势，也没有可识别的医疗风险因素。总死亡率为 22%。脑静脉窦血栓形成患者的死亡几率每降低 50%，死亡几率增加 2.7 倍（95% 置信区间 [CI]，1.4 至 5.2），增加 1.7 倍（95% CI，1.3 至 2.3）在基线血小板计数中，基线d每增加 10,000 个纤维蛋白原当量单位，因子 1.2（95% CI，1.0 到 1.3）-二聚体水平，基线纤维蛋白原水平每降低 50%，系数为 1.7（95% CI，1.1 至 2.5）。多变量分析确定基线血小板计数和颅内出血与死亡独立相关；在血小板计数低于 30,000/mm 和颅内出血的患者中，观察到的死亡率为 73%。

结论

在血小板计数低和颅内出血的患者中，与 VITT 相关的高死亡率最高。治疗仍然不确定，但预后标志物的识别可能有助于指导有效的管理。（由牛津大学医院 NHS 基金会信托基金资助。）