Can someone with some scientific knowledge help me understand the type of “blood clots”after AZ.

[2boysand1princess]

I thought blood clots are a result of fatty deposits in your blood or when the platelets are very high which can cause blood to clot too easily.
Whenever there is a risk of a blood clot them the treatment is usually blood thinners such as heparin, which I have had after every c section as standard after care.
However, on the briefing today the blood clots were described as similar to heparin induced thrombocytopenia and is usually due to low levels of platelets. How does that happen then? Thought low platelets meant blood doesn’t clot?
And also, how is this treated? Are people who are on blood thinners such as aspirin etc for other reasons, at higher risk?
Sorry I’m just genuinely interested, but my scientific knowledge is very limited. Only thing I know about blood thinners and clots is from having had 3 c sections and being told to take heparin injections for 14 days after each one. I’ve had the Pfizer back in February, so doesn’t directly affect me, however I am interested to understand this better for my parents who have had the AZ and many more family and friends who will go on and have AZ.
After the briefing today I feel reassured that the risks are minuscule and I probably had more risks after my 3 emergency c sections. I feel relief knowing this as my parents still haven’t had their second AZ doses.

It was explained in the news conference and some articles after that it could be an immune reaction to the vaccine that makes the body think the platelets are like the virus and your body would then try to get rid of them. Hence the low platelets... which then makes the body produce lots more to replace the lost ones which then causes a clot if there are now too many.

@nordica

It was explained in the news conference and some articles after that it could be an immune reaction to the vaccine that makes the body think the platelets are like the virus and your body would then try to get rid of them. Hence the low platelets... which then makes the body produce lots more to replace the lost ones which then causes a clot if there are now too many.

Thank you for explaining. So, it’s still a clot due to high levels of platelets then. Highly levels caused by an initial drop in platelets. I was just confused about that bit 👍🏻

@nordica, thank you for explaining.
I thought clots are made of platelets. In my limited understanding I thought the clots would be trying to block virus spreading through the body but maybe not.
I wish I was more medical....

From googling it: www.uptodate.com/contents/image?topicKey=90261&search=HIT&source=outline_link&imageKey=HEME%2F50473

It seems that in HIT, the body produces an antibody which binds to heparin. The bound antibody then also binds and activates platelets, which causes them to release chemicals which activate clotting proteins in the blood - which causes clot formation (clots need both activated clotting proteins and platelets to form).

The reduction in platelets is due to the spleen clearing the platelets bound to antibody. And also platelets being used in clot formation. So it’s a result rather than cause of the problem.

I guess with the vaccine then it’s probably the body producing antibody which binds the virus protein and then the bound antibody also binds platelets and activates them? Then maybe the same mechanism as HIT - where activated platelets release chemicals to activate clotting and start clot formation etc. Just a guess though - I think they are probably doing research into it.

Ps - I think there are other non related conditions where the low platelets is caused by another reason (eg low production or abnormal shape so they are removed by the body) - these conditions may have an increased bleeding tendency (rather than clotting tendency).