Vaccine-induced Immune Thrombotic Thrombocytopenia (VITT)
Evidence is growing of a link between the Covid-19 vaccine and a deadly thrombosis – and theories are emerging as to why - Melissa Davey
image by: Harpreet Tsui
HWN Recommends
The Blood-Clot Problem Is Multiplying
For weeks, Americans looked on as other countries grappled with case reports of rare, sometimes fatal blood abnormalities among those who had received the AstraZeneca vaccine against COVID-19. That vaccine has not yet been authorized by the FDA, so restrictions on its use throughout Europe did not get that much attention in the United States. But Americans experienced a rude awakening this week when public-health officials called for a pause on the use of the Johnson & Johnson vaccine, after a few cases of the same, unusual blood-clotting syndrome turned up among the millions of people in the country who have received it.
The world is now engaged in a vaccination program unlike anything…
Resources
Thrombosis with Thrombocytopenia Syndrome (also termed Vaccine-induced Thrombotic Thrombocytopenia)
Thrombosis with Thrombocytopenia Syndrome (also termed Vaccine-induced Thrombotic Thrombocytopenia)
What is thrombocytopenia, the rare blood condition possibly linked to the AstraZeneca vaccine?
As we continue to vaccinate the world, it’s likely small subsets of people will continue to experience this complication. Whether we can establish a causal link between the AstraZeneca vaccine and thrombocytopenia is subject to continued investigation.
Blood clot fears: how misapplication of the precautionary principle may undermine public trust in vaccines
The number of blood clots reported among people taking the vaccine, assuming even a fairly high level of under-reporting, does not seem to be higher than would be expected in the general population. Many things happen after vaccination that would have happened without the vaccine. That said, in some countries, such as Norway and Germany, an extremely rare form of blood clot in the brain called cerebral venous sinus thrombosis (CVST) has been reported. Incidence of CVST in the normal population is hard to measure, although Johns Hopkins Medicine has said it may affect around one in every 200,000 people each year.
Blood Clots and the AZ Vaccine, Revisited
A possible concern is what’s being called vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) by Andreas Greinacher at Univ. Griefswald. This is a blood clotting syndrome that’s similar to what’s observed with the (already known) syndrome of heparin-induced thrombocytopenia. That problem, first over 40 years ago, is a paradoxical effect that occurs in a few people of administering heparin for blood clotting problems and actually making the situation worse.
Immune Thrombocytopenia Purpura (ITP) and Vaccines
ITP usually occurs when the immune system mistakenly attacks and destroys blood platelets. If the cause of the immune reaction is unknown, the condition is called idiopathic thrombocytopenic purpura.
The Blood-Clot Problem Is Multiplying
So are theories to explain it.
AstraZeneca blood clotting: what is this rare syndrome and how is it caused?
Evidence is growing of a link between the Covid-19 vaccine and a deadly thrombosis – and theories are emerging as to why.
J&J Covid-19 Vaccine Pause Spotlights Science of Rare Clotting Disorder
The J&J vaccine recipients who experienced the rare clotting condition were diagnosed with cerebral venous sinus thrombosis, or CVST, which involves the formation of clots within large blood vessels in the brain. That was accompanied by a drop in platelet levels.
Rare blood clots - what you need to know
Most cases have been seen between four days and a few weeks of people having the jab. Medical experts in the UK now suggest doctors should consider this rare condition as a diagnosis in anyone who has matching symptoms up to a month after they have had the vaccine.
Why would a Covid vaccine cause rare blood clots? Researchers have found clues
Is some part of the adenovirus mimicking platelet factor 4? If so, would that same mimicry occur with other adenoviruses? There’s no clear answer. But Offit suspects it’s a class-wide problem, meaning the same phenomenon associated with AstraZeneca’s vaccine is associated with Johnson & Johnson’s. “There is going to be something about the adenovirus — whether it’s adenoviral DNA or an adenovirus protein — that complexes with platelet factor 4. So that will be determined, I suspect soon.”
Introducing Stitches!
Your Path to Meaningful Connections in the World of Health and Medicine
Connect, Collaborate, and Engage!
Coming Soon - Stitches, the innovative chat app from the creators of HWN. Join meaningful conversations on health and medical topics. Share text, images, and videos seamlessly. Connect directly within HWN's topic pages and articles.
