10 May 2021

An expert team of our peers have recently been involved in diagnosing and managing a rare syndrome of thrombosis associated with low platelets which occurs after Astra Zeneca vaccine.

The thrombosis is rapidly progressive and there is a high preponderance of cerebral venous sinus thrombosis. Arterial thrombotic events have also been noted. Testing typically reveals low fibrinogen and very raised D-Dimer levels above the level typically expected in venous thromboembolism. Antibodies to platelet factor 4 (PF4) have been identified, hence there are similarities to heparin-induced thrombocytopenia despite the absence of prior exposure to heparin treatment. The anti PF4 antibodies can be detected by the ELISA HIT assay but not usually with other HITT assays.

It is important that the correct management is applied to prevent the progression of thrombosis. Of critical note, intravenous immunoglobulin should be given immediately and platelet transfusions avoided.

This is an immune condition and there is no evidence that individuals with a prior history of thrombosis or known risk factors for thrombosis are more at risk. For the majority of individuals, the risk of recurrent thrombosis due to Covid-19 infection is greater than the risk of this syndrome.

Please read this link for the latest Guidance produced by the Expert Haematology Panel (EHP) focussed on VITT, contact details for advice from the Expert Haematology Panel are included in the document, as well as links to report your case.

A list of UK Laboratories Offering HIT ELISA testing can be found here.

This document outlines the Haematology triage policy for patients with previous vaccine-induced immune thrombocytopenia and thrombosis (VITT) 

This is a leaflet that can be printed out and given to patients

As this is an emerging area of practice, please continue to check back for updates and to monitor the literature for publications.


Important Notice Please read: Letter to MHRA from the Expert Haematology Panel endorsed by Thrombosis UK 13.00 8 April 2021


Media Statement on syndrome of Thrombosis and Thrombocytopenia occurring after coronavirus vaccination

BSH has informed the UK haematological community about this complication and is working with the Expert Haematology Panel to issue regular updated guidance as to how to best investigate and manage this condition.

The Expert Haematology Panel comprises of specialists in immunohaematology haemostasis and thrombosis (or blood clotting and immune causes of reduced platelets), who hold daily meetings to support clinicians managing these patients and learn from new cases. They are in regular communication with the regulators, other UK medical and surgical societies, multidisciplinary groups and international haematology colleagues focussed on this condition.

The Expert Haematology Panel has been instrumental in describing this condition and its management and continues to work closely with PHE and regulatory authorities. BSH is working with the EHP to make sure the haematology community is kept up to date with the latest information on this syndrome.  We have received many requests from media for information and interviews and we have done our best to advise and inform wherever possible. However, all our members have responsibilities as NHS clinicians which are their priority roles.  We will therefore be unable to respond to further media requests and if additional information is required please contact the MHRA.


For the General Public

We aim to provide members with both general and haematology specific up-to-date COVID-19 information. This advice is for healthcare professionals. Patients looking for further information on this condition are advised to speak to their healthcare providers, who are best placed to answer specific questions. Patients may also be able to get information from their patient support groups, some of them can be found listed here

This is a leaflet that can be printed out and given to patients