CC BY-NC-ND 4.0 · Thromb Haemost 2021; 121(12): 1677-1680
DOI: 10.1055/a-1585-6182
Letter to the Editor

Venous Thromboembolism and Mild Thrombocytopenia after ChAdOx1 nCoV-19 Vaccination

Nadia Gabarin*
1  Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
,
Sarah Patterson*
2  Department of Medicine, Hamilton Health Sciences, Hamilton, Ontario, Canada
,
Menaka Pai
1  Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
2  Department of Medicine, Hamilton Health Sciences, Hamilton, Ontario, Canada
3  McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
4  Department of Pathology and Molecular Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
,
Tamoor Afzaal
1  Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
,
Ishac Nazy
1  Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
3  McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
,
Jo-Ann I. Sheppard
4  Department of Pathology and Molecular Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
,
Donald M. Arnold
1  Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
2  Department of Medicine, Hamilton Health Sciences, Hamilton, Ontario, Canada
3  McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
,
1  Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
2  Department of Medicine, Hamilton Health Sciences, Hamilton, Ontario, Canada
3  McMaster Center for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
4  Department of Pathology and Molecular Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
› Author Affiliations
Funding Funding support for this work was provided by a grant from the Canadian Institutes of Health Research (CIHR #452655) awarded to Dr. Ishac Nazy.

Thrombocytopenia and thrombosis have been reported following vaccination with the ChAdOx1 nCoV-19 (AstraZeneca) vaccine, an adenoviral vector COVID-19 (coronavirus disease 2019) vaccine.[1] [2] [3] [4] [5] Previous cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) have been reported with symptom onset between 5 to 30 days postvaccination, typically with severe thrombocytopenia, unusual thromboses, high mortality, and platelet-activating antibodies against platelet factor 4 (PF4) despite no previous exposure to heparin.[1] [2] [3] Here we report two patients with VITT presenting as lower limb venous thrombosis (one with concurrent pulmonary embolism) and mild thrombocytopenia. One had a late presentation 31 days postvaccination. Both patients were shown to have platelet-activating antibodies in a PF4-dependent serotonin-release assay (SRA).

Author Contributions

N.G., T.A., and S.P. delivered patient care and provided clinical data; N.G. and T.A. prepared the initial manuscript draft. I.N. and D.M.A. provided laboratory supervision. M.P. supervised the clinical data collection. J.I.S. reviewed laboratory data and devised an explicatory figure. T.E.W. interpreted the data and provided critical revisions to the manuscript. All authors reviewed drafts of the paper and approved the final version of this communication.


* These authors contributed equally to this work.




Publication History

Received: 10 June 2021

Accepted: 06 August 2021

Publication Date:
12 August 2021 (online)

© 2021. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)

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