CC BY 4.0 · TH Open 2023; 07(04): e303-e308
DOI: 10.1055/a-2183-5269
Original Article

Comparison of Venous Thromboembolism Outcomes after COVID-19 and Influenza Vaccinations

Manila Gaddh
1   Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, Georgia, United States
2   Department of Hematology and Medical Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
Waldemar E. Wysokinski
3   Versiti, Blood Research Institute, Milwaukee, Wisconsin, United States
Robert D. McBane
3   Versiti, Blood Research Institute, Milwaukee, Wisconsin, United States
Ana I. Casanegra
3   Versiti, Blood Research Institute, Milwaukee, Wisconsin, United States
Lisa Baumann Kreuziger
2   Department of Hematology and Medical Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
4   Division of Vascular Medicine, Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States
Damon E. Houghton
3   Versiti, Blood Research Institute, Milwaukee, Wisconsin, United States
5   Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, Minnesota, United States
› Institutsangaben


Background Published data on the risk of venous thromboembolism (VTE) with coronavirus disease 2019 (COVID-19) vaccines are scarce and inconclusive, leading to an unmet need for further studies.

Methods A retrospective, multicentered study of adult patients vaccinated for one of the three approved COVID-19 vaccines in the United States of America and a pre-COVID-19 cohort of patients vaccinated for influenza at two institutions: Mayo Clinic Enterprise sites and the Medical College of Wisconsin, looking at rate of VTE over 90 days. VTE was identified by applying validated natural language processing algorithms to relevant imaging studies. Kaplan–Meier curves were used to evaluate rate of VTE and Cox proportional hazard models for incident VTE after vaccinations. Sensitivity analyses were performed for age, sex, outpatient versus inpatient status, and type of COVID-19 vaccine.

Results A total of 911,381 study subjects received COVID-19 vaccine (mean age: 56.8 [standard deviation, SD: 18.3] years, 55.3% females) and 442,612 received influenza vaccine (mean age: 56.5 [SD: 18.3] years, 58.7% females). VTE occurred within 90 days in 1,498 (0.11%) of the total 1,353,993 vaccinations: 882 (0.10%) in the COVID-19 and 616 (0.14%) in the influenza vaccination cohort. After adjusting for confounding variables, there was no difference in VTE event rate after COVID-19 vaccination compared with influenza vaccination (adjusted hazard ratio: 0.95 [95% confidence interval: 0.85–1.05]). No significant difference in VTE rates was observed between the two cohorts on sensitivity analyses.

Conclusion In this large cohort of COVID-19-vaccinated patients, risk of VTE at 90 days was low and no different than a pre-COVID-19 cohort of influenza-vaccinated patients.

Author Contributions

All authors were involved in conceptualization and design of the study, analysis and interpretation of the data, and drafting or critical revision of the manuscript. All authors read and approved the final manuscript.

Supplementary Material


Eingereicht: 20. Juni 2023

Angenommen: 25. September 2023

Accepted Manuscript online:
28. September 2023

Artikel online veröffentlicht:
04. Dezember 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (

Georg Thieme Verlag KG
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