A history of blood clots is usually not a reason to avoid the AstraZeneca vaccine

Melbourne: As hematologists, we care for many patients who have had blood clots or have taken anticoagulants in the past. They often ask: AstraZeneca vaccine? ”
The answer is usually the definitive “yes”. The blood clots seen after vaccination with AstraZeneca are quite different from other types of blood clots, such as deep vein thrombosis, pulmonary embolism, and blood clots that cause heart attacks and strokes.
People with this type of medical history do not appear to be at increased risk from the AstraZeneca vaccine.
In fact, people in this group may be at high risk for COVID-19, so there is no need to delay vaccination.
First, how does blood form a blood clot?
Blood flows through the blood vessels of our body as a liquid, carrying oxygen, nutrients, proteins, and immune cells to all organs. However, if you are injured or have surgery, your body needs to close the wound to stop the bleeding.
Our blood contains components that quickly change from a liquid to a semi-solid clot in seconds.
When the first signs of injury appear, the smallest blood cells, platelets, attach to the damaged vessel wall and, along with the damaged wall itself, attract large amounts of coagulating proteins that accumulate at the site of injury and bind the wound. ..
Venous thrombosis
The natural and anticoagulant processes in the blood may become unbalanced, increasing the risk of blood clots in the veins. This can happen to people.
–Suffering from cancer or infection
–For those who are pregnant
–People taking estrogen-containing contraceptives
–People who get stuck during and after surgery or after major trauma
–People who have a specific genetic disorder.
In all of these cases, abnormal blood clots can occur in the deep veins (deep vein thrombosis) or lungs (pulmonary embolism) in the thighs and groin.
In rare cases, blood clots may form elsewhere, such as in the veins in the abdomen or in the brain.
Arterial thrombus
The arteries that supply blood to the heart, brain, and lower extremities can usually be narrowed due to risk factors such as smoking, diabetes, high blood pressure, and cholesterol.
The formation of blood clots in these areas can block blood flow and cause, for example, a heart attack or stroke.
What is TTS?
The AstraZeneca vaccine is associated with a rare condition called thrombosis. Thrombocytopenia Syndrome, or TTS. Cases of this condition have also been reported after Johnson & Johnson. COVID There is no vaccine, Australia..
We now know more about this condition than we did a few months ago.
TTS is triggered by an abnormal immune response that causes the development of antibodies directed at platelets (blood cells that prevent bleeding). This causes platelets to become hyperactive, forming blood clots in the body, including areas where blood clots are not normally found, such as the brain and abdomen.
This process also consumes platelets, which reduces the number of platelets. The name “thrombosis” refers to blood clots, and “thrombocytopenia” means a low number of platelets.
The Australian Immunotechnology Advisory Group (ATAGI) recently estimated the risk of TTS in Australia for 100,000 doses of the AstraZeneca vaccine to people over the age of 50, but this data shows more people. Can change as you get the vaccine.
Fortunately, the diagnosis and treatment of TTS is advancing rapidly. Doctors are now aware of the symptoms to watch out for, and hematologists are identifying treatments for those symptoms. These include intravenous immunoglobulin (a concentrate of antibodies from healthy donors) and blood diluents.
Outcomes for TTS patients have improved significantly worldwide since this condition was first recognized earlier this year. In Australia, most TTS patients are recovering or are recovering.
Do not delay vaccination
There is no evidence that people who have previously experienced blood clots, who are at genetic risk for blood clots, or who are taking anticoagulants or related drugs are at increased risk of TTS.
The mechanism of TTS, an immune-driven disease that causes platelet overactivity, is quite different from other types of blood clots.
From this perspective, ATAGI recently advised that the AstraZeneca vaccine is safe for these people.
As a precautionary measure, Australian guidelines indicate that certain people avoid the AstraZeneca vaccine. Pfizer Jab instead. These include people:
–People who have a previous episode of heparin-induced thrombocytopenia (TTS’s “cousin”)
–People with venous thrombosis in the brain or abdomen
–Patients with a very rare antibody-driven coagulation disorder called antiphospholipid antibody syndrome
・ Those under 50 years old.
It is important to remember that people with risk factors for heart attack or stroke, such as diabetes and high blood pressure, are at increased risk of developing severe COVID-19 when infected. In addition, COVID itself makes the blood more “sticky”, greatly increasing the risk of blood clots.
If you have previously experienced deep vein thrombosis, pulmonary embolism, heart attack, or stroke, vaccination does not increase your risk of TTS. You should be vaccinated as soon as you qualify.
Source: (The Conversation)