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. 2021 Oct 28;385(18):1680-1689.
doi: 10.1056/NEJMoa2109908. Epub 2021 Aug 11.

Clinical Features of Vaccine-Induced Immune Thrombocytopenia and Thrombosis

Sue Pavord  1 , Marie Scully  1 , Beverley J Hunt  1 , William Lester  1 , Catherine Bagot  1 , Brian Craven  1 , Alex Rampotas  1 , Gareth Ambler  1 , Mike Makris  1
Affiliations

Clinical Features of Vaccine-Induced Immune Thrombocytopenia and Thrombosis

Sue Pavord et al. N Engl J Med. .

Abstract

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.).

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Figures

Figure 1
Figure 1. Baseline Distribution of Variables in Patients with Vaccine-Induced Immune Thrombocytopenia and Thrombosis (VITT).
Shown are the variables in patients with VITT, including those who did not survive.
Figure 2
Figure 2. Sites of Disease in 220 Patients with Definite or Probable VITT.
Sites of disease (thrombosis or bleeding) that are not shown include the bowel and the pelvic, retinal, ophthalmic, and internal jugular veins.
See this image and copyright information in PMC

Comment in

  • Clinical Features of VITT.
    Chiti A. Chiti A. N Engl J Med. 2022 Jan 6;386(1):10.1056/NEJMc2118473#sa1. doi: 10.1056/NEJMc2118473. Epub 2021 Dec 22. N Engl J Med. 2022. PMID: 34936756 No abstract available.

References

    1. Worldometer. Covid-19 coronavirus pandemic. July 8, 2021. (https://www.worldometers.info/coronavirus/).
    1. Mathieu E, Ritchie H, Ortiz-Ospina E, et al. A global database of COVID-19 vaccinations. Nat Hum Behav 2021. May 10 (Epub ahead of print). - PubMed
    1. Ramasamy MN, Minassian AM, Ewer KJ, et al. Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial. Lancet 2021;396:1979-1993. - PMC - PubMed
    1. Voysey M, Clemens SAC, Madhi SA, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet 2021;397:99-111. - PMC - PubMed
    1. Gov.UK. First people to receive Oxford University/AstraZeneca COVID-19 vaccine today. Press release. January 7, 2021. (https://www.gov.uk/government/news/first-people-to-receive-oxford-univer...).

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