In March 2021 the first reports of an extremely rare adverse event of concurrent thrombosis (blood clots) and thrombocytopenia (low platelet count) following the Oxford Astra-Zeneca COVID vaccination were reported. This new syndrome was named Vaccine-induced Immune Thrombosis and Thrombocytopenia (VITT).
Vaccine-induced Immune Thrombosis and Thrombocytopenia is a very rare immune condition. Patients with VITT have a unique antibodies to platelet factor 4 (PF4). The antibodies cause activation of the platelets and the blood clotting system, leading to clots (thrombosis) forming in the blood vessels, and a low platelet count as the platelets are used up in the process.
VITT causes blood clots to form in the blood vessels in different parts of the body including the brain, liver, gut, heart, legs, lungs and kidneys and is considered a medical emergency that can be fatal, even if treated appropriately. If suspected, VITT needs urgent medical attention.
Associated with the COVID-19 vaccines, in particular Oxford Astra-Zeneca and Johnson and Johnson, VITT is extremely rare. Currently there are no clear risk factors to identify those who may be at increased risk, it affects women and men to a similar extent and can affect people of all ages however many of cases reported have been in people under 50 years of age.
Symptoms start five or more days after a COVID-19 vaccine and often occur at unusual sites in the body.
Other symptoms can include:
As COVID vaccinations continued to be monitored, via the 'yellow card' system.
The Medicines and Healthcare and products Regulatory Agency (MHRA) and the Joint Committee on Vaccination and Immunisation (JCVI) continually review evidence and updated guidance accordingly.
In March 2021 the Expert Haematology Panel (EHP) was set up. This team of experts have daily meetings to review suspected cases of VITT and have developed Living Guidance for clinicians in the prevention and management of VITT and a Patient Information fact sheet on VITT, endorsed by Thrombosis UK.
Thrombosis UK has and continues to liaise with all professional bodies to ensure up to date and accurate information is shared and the experiences of those diagnosed with VITT or concerned about the risk of VITT are shared with the committees.
In this tutorial, Beverley outlines the risk of thrombosis in Long COVID, including what we know so far about thrombosis risk, seated immobility syndrome which does increase risk of blood clots, and what, if anything, does a D-dimer test tell us about someone’s risk of blood clots.
In this tutorial, Beverley discussed blood clots in acute COVID-19 infection, including who is at risk, the types of thrombosis seen, and what preventative measures are recommended for moderately and severely unwell patients.
In this tutorial, Beverley introduces vaccine-induced immune thrombocytopenia and thrombosis syndrome, an extremely rare immune response to a vaccine causing thrombosis (blood clots) and thrombocytopenia (low platelet count), most commonly following the Astra-Zeneca vaccine.
Published August 11th 2021
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.
This is a living guideline which means that it will be updated in real-time to take account of changes in clinical practice and emerging evidence.
NICE methods and processes for a living guideline include:
Thrombosis UK is not aware of any current and specific psychological support service for patients and families affected Vaccine-induced Immune Thrombosis and Thrombocytopenia (VITT), although we have approached NHS bodies to seek an update on proposed services.
If you have been affected by VITT and would like to talk with someone, we do have a Helpline open most weekdays. The Helpline can offer information and supportive psychotherapy, but please be aware this is manned by Thrombosis UK staff with a wealth of experience in thrombosis but who are not trained to provide psychological /professional counselling services. However, sometimes a supportive conversation trying to make sense of the events and information about VITT and thrombosis can be a huge help, so please do consider this if you feel it may be of help.
Thrombosis UK has a range of support resources that are medically and peer reviewed.
Our resources are free of charge and can be downloaded. These include:
Pod cast on BBC Sounds with professor Beverly Hunt OBE - ‘What we understand about COVID-19 vaccines’
Thrombosis UK has sent a letter to Dr June Raine CBE, CEO of MHRA, expressing our concern regarding wording in the MHRA guidance on the use of the AstraZeneca COVID-19 vaccine.
Letter from the Expert Haematology Panel and endorsed by Thrombosis UK, to the Medicines and Healthcare products Regulatory Agency (MHRA).
We wish to raise our concern with the MHRA regarding wording included in recent changes in MHRA guidance on the use of the AstraZeneca COVID-19 vaccine.