Pathologic Antibodies to Platelet Factor 4 after ChAdOx1 nCoV-19 Vaccination.

Scully, Marie, Singh, Deepak, Lown, Robert, Poles, Anthony, Solomon, Thomas, Levi, Marcel, Goldblatt, David, Kotoucek, Pavel, Thomas, William and Lester, William (2021) Pathologic Antibodies to Platelet Factor 4 after ChAdOx1 nCoV-19 Vaccination. The New England journal of medicine. ISSN 1533-4406. This article is available to all UHB staff and students via ASK Discovery tool http://tinyurl.com/z795c8c by using their UHB Athens login IDs

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Official URL: http://content.nejm.org/

Abstract

BACKGROUND

The mainstay of control of the coronavirus disease 2019 (Covid-19) pandemic is vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Within a year, several vaccines have been developed and millions of doses delivered. Reporting of adverse events is a critical postmarketing activity.

METHODS

We report findings in 23 patients who presented with thrombosis and thrombocytopenia 6 to 24 days after receiving the first dose of the ChAdOx1 nCoV-19 vaccine (AstraZeneca). On the basis of their clinical and laboratory features, we identify a novel underlying mechanism and address the therapeutic implications.

RESULTS

In the absence of previous prothrombotic medical conditions, 22 patients presented with acute thrombocytopenia and thrombosis, primarily cerebral venous thrombosis, and 1 patient presented with isolated thrombocytopenia and a hemorrhagic phenotype. All the patients had low or normal fibrinogen levels and elevated d-dimer levels at presentation. No evidence of thrombophilia or causative precipitants was identified. Testing for antibodies to platelet factor 4 (PF4) was positive in 21 patients, negative in 1 patient, and equivocal in 1 patient. On the basis of the pathophysiological features observed in these patients, we recommend that treatment with platelet transfusions be avoided because of the risk of progression in thrombotic symptoms and that the administration of a nonheparin anticoagulant agent and intravenous immune globulin be considered for the first occurrence of these symptoms.

CONCLUSIONS

Vaccination against SARS-CoV-2 remains critical for control of the Covid-19 pandemic. A pathogenic PF4-dependent syndrome, unrelated to the use of heparin therapy, can occur after the administration of the ChAdOx1 nCoV-19 vaccine. Rapid identification of this rare syndrome is important because of the therapeutic implications.

Item Type: Article
Additional Information: This article is available to all UHB staff and students via ASK Discovery tool http://tinyurl.com/z795c8c by using their UHB Athens login IDs
Subjects: WG Cardiovascular system. Cardiology
WH Haemic and lymphatic systems. Haematology
Divisions: Planned IP Care > Oncology and Clinical Haematology
Related URLs:
Depositing User: Jamie Edgar
Date Deposited: 23 Apr 2021 15:02
Last Modified: 23 Apr 2021 15:02
URI: http://www.repository.uhblibrary.co.uk/id/eprint/4247

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