Thrombosis patterns and clinical outcome of COVID-19 vaccine-induced immune thrombotic thrombocytopenia: A Systematic Review and Meta-Analysis

Ah Young Kim, Wongi Woo, Dong Keon Yon, Seung Won Lee, Jae Won Yang, Ji Hong Kim, Seoyeon Park, Ai Koyanagi, Min Seo Kim, Sungsoo Lee, Jae Il Shin, Lee Smith

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


Objectives: To meta-analyse the clinical manifestations, diagnosis, treatment, and mortality of vaccine-induced immune thrombotic thrombocytopenia (VITT) after adenoviral vector vaccination. Methods: Eighteen studies of VITT after ChAdOx1 nCoV-19 or Ad26.COV2.S vaccine administration were reviewed from PubMed, Scopus, Embase, and Web of Science. The meta-analysis estimated the summary effects and between-study heterogeneity regarding the incidence, manifestations, sites of thrombosis, diagnostic findings, and clinical outcomes. Results: The incidence of total venous thrombosis after ChAdOx1 nCoV-19 vaccination was 28 (95% CI 12-52, I2=100%) per 100,000 doses administered. Of 664 patients included in the quantitative analysis (10 studies), the mean age of patients with VITT was 45.6 years (95% CI 43.8-47.4, I2=57%), with a female predominance (70%). Cerebral venous thrombosis (CVT), deep vein thrombosis (DVT)/pulmonary thromboembolism (PE), and splanchnic vein thrombosis occurred in 54%, 36%, and 19% of patients with VITT, respectively. The pooled incidence rate of CVT after ChAdOx1 nCoV-19 vaccination (23 per 100,000 person-years) was higher than that reported in the pre-pandemic general population (0.9 per 100,000 person-years). Intracranial haemorrhage and extracranial thrombosis accompanied 47% and 33% of all patients with CVT, respectively. The antiplatelet factor 4 antibody positivity rate was 91% (95% CI 88-94, I2=0%) and the overall mortality was 32% (95% CI 24-41, I2=69%), and no significant difference was observed between heparin- and non-heparin-based anticoagulation treatments (risk ratio 0.84, 95% CI 0.47-1.50, I2=0%). Conclusions: Patients with VITT after SARS-CoV-2 vaccination most frequently presented with CVT following DVT/PE and splanchnic vein thrombosis, and about one-third of patients had a fatal outcome. This meta-analysis should provide a better understanding of VITT and assist clinicians in identifying VITT early to improve outcomes and optimise management.

Original languageEnglish
Pages (from-to)130-139
Number of pages10
JournalInternational Journal of Infectious Diseases
Publication statusPublished - 2022 Jun

Bibliographical note

Publisher Copyright:
© 2022

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)
  • Infectious Diseases


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