CVST with thrombocytopenia is a rare but potentially life threatening condition that emerged in people after vaccination with one of two COVID-19 vaccine types. Symptoms can persist long-term, but treatment is available.
In 2021, medical professionals noticed a rare type of blood clotting disorder in the brain called cerebral venous sinus thrombosis (CVST) occurring together with low levels of blood platelets (thrombocytopenia). Reports generally followed vaccination with two recently developed COVID-19 vaccines.
The two vaccines, developed on the adenoviral vector-based platform, were ChAdOx1-S, developed by Oxford (first named AstraZeneca and later Vaxzevria) and Ad26.COV2-S (first named Janssen and later Jcovden).
The Vaxzevria vaccine was never approved in the United States, and the Jcovden is still approved but for restricted use. Worldwide, approvals of the two vaccines vary. The
The COVID-19 vaccines Pfizer and Moderna developed on a different platform called messenger RNA (mRNA) were not implicated with VITT.
CVST occurrence with thrombocytopenia following COVID-19 vaccination was termed “vaccine-induced thrombotic thrombocytopenia (VITT) with CVST” by researchers who first documented it.
This article explores the collective relationship of CVST, thrombocytopenia, and VITT, and discusses symptoms, diagnosis, and treatment of this rare new syndrome.
VITT is a newly identified syndrome that emerged as a rare adverse reaction to two COVID-19 adenoviral vector vaccines, namely the Vaxzevria and Jcovden vaccines.
VITT has only been known to occur in reaction to these two COVID vaccines.
According to research, the vaccination of millions of people has resulted in over 100 people being diagnosed with VITT. Though rare, VITT can be life threatening or lead to long-term disability.
In the context of COVID-19 vaccination, research has associated VITT with hemorrhage in the brain that can lead to stroke and death. It is characterized by the following:
- venous or arterial thrombosis (blood clotting)
- thrombocytopenia (low blood platelet counts)
- presence of antibodies against platelet factor 4 (PF4)
CVST with thrombocytopenia does not always have to be related to vaccines.
Since VITT with CVST is a new syndrome, its exact causes are unknown.
VITT onset is triggered by a dose of one of the two adenoviral vaccines for COVID-19. Symptoms occur within 30 days of vaccination. Also, VITT does not appear to emerge initially during long COVID.
Doctors have settled on calling the possibility of blood clots related to vaccination by the two adenovirus vector vaccines a risk factor or a rare complication of VITT, rather than a cause. Other risk factors
- being female
- being younger than age 60 years
- other risk factors generally associated with CVST, include:
- exposure to certain medications, such as oral contraceptives and chemotherapy
- infections, especially in the central nervous system, ears, or face
- head trauma
CVST by itself is a blood clot in one of the brain’s large veins. It is considered to be a form of stroke because it often produces bleeding in the brain. This type of stroke is very rare, accounting for fewer than
The VITT syndrome can begin 5 to 10 days after vaccination. That said, people may receive a diagnosis 5 to 30 days (or longer) after vaccination depending on the clot location.
According to the American Society of Hematology, symptoms of VITT include:
- nausea and vomiting
- pain in abdomen
- shortness of breath
- back pain
- bruising or bleeding more easily than usual
- swelling or pain in the legs
- severe headache
- changes in vision
For a person to be diagnosed with VITT, five conditions must be met:
- presence of thrombosis (blood clot)
- low platelet count (thrombocytopenia)
- the onset of symptoms 5 to 30 days after vaccination against COVID-19
- very high D-dimer and fibrinogen levels (indicators of a blood clotting problem)
- presence of antibodies to PF4 platelets
Laboratory tests for VITT usually include:
- a complete blood count (CBC)
- coagulation testing
- PF4 antibody testing
- imaging tests to determine where the clot is
Learn more about coagulation disorders and tests doctors might perform here.
A treatment plan may include the following:
- Anticoagulation: Non-heparin anticoagulation medication is the primary treatment for VITT.
- IVIG: High doses of intravenous immune globulin (IVIG) can help control the PF4 antibody response.
- Plasma exchange: A plasma exchange helps remove harmful substances from the blood.
- Bleeding treatment:
Researchhas noted the challenge of managing bleeding in VITT because of the two competing goals, which are stopping bleeding and preventing clotting. Input from a consulting hemostasis specialist is usually beneficial.
Complications of VITT include many of the same ones seen for CVST itself:
- speech problems
- movement difficulties
- vision problems
- brain injury
Some cases may be fatal. A 2021 study calculated a 23% fatality rate among VITT cases. Increased mortality was more likely when people with VITT initially experienced the following:
- severe thrombocytopenia
- brain hemorrhage
- severe coagulation problems
VITT can be prevented by avoiding the two adenoviral COVID-19 vaccines, especially for those with a history of thrombosis with thrombocytopenia.
CVST and thrombocytopenia each have their own preventive measures, including:
- CVST: stopping smoking and avoiding oral contraceptives
- Thrombocytopenia: avoiding drinking alcohol excessively, minimizing contact with toxic chemicals like pesticides and benzenes, and being aware of any medications that may raise the risk of bleeding
It is not yet known how long VITT symptoms can last. There are
- laboratory testing
- immunological treatments
- brain imaging
- revising and tweaking treatments
Although research is limited, it is likely there is a mental health component to VITT. People should talk with their doctor if they feel they need mental health support in coping with this diagnosis.
VITT syndrome refers to a potentially life threatening blood clotting disorder that emerged in a rare reaction to two adenoviral COVID-19 vaccines, namely the Vaxzevria and Jcovden vaccines. Worldwide approvals of the two vaccines vary.
Sometimes, thrombocytopenia can occur with CVST, but this is very rare.
WHO approves both vaccines for adults. It acknowledges the risk of blood clots but says the benefits of the vaccines outweigh the risk. The mRNA COVID-19 vaccines Pfizer and Moderna were not implicated with VITT.
VITT can lead to brain hemorrhages that cause strokes that can result in disability or death. Treatment is available and is most effective when started early. The effects of VITT can be long-term.
Researchers are working to develop new treatments.