AZ COVID Vaccine: Causal Link to Severe Thrombosis Established

[Northerner]

Two scientific studies establishing a causal relationship between the AstraZeneca COVID-19 vaccine and severe thrombotic complications have now been published.

The articles — one from a German/Austrian/Canadian collaboration and one from a Norwegian group — were published online April 9 in the New England Journal of Medicine.

A preliminary report of the German-led study was first published as a preprint on Research Square on March 28.

Both articles reach the same conclusion — that these unusual severe thrombotic events that are accompanied by thrombocytopenia are caused by rogue antibodies directed against platelet factor 4 (PF4), which causes massive platelet aggregation and thrombosis, and results in a reduced platelet count elsewhere, leading in turn to bleeding. Patients can therefore have both severe thrombosis and severe bleeding.

The syndrome is very similar to the well-known condition of heparin-induced thrombocytopenia (HIT) and is diagnosed and treated in the same way, with the administration of intravenous immunoglobulins (IVIG) and anticoagulants. The syndrome associated with the vaccine has been named vaccine-induced immune thrombotic thrombocytopenia (VITT).

AZ COVID Vaccine: Causal Link to Severe Thrombosis Established

Two articles giving more details of the mechanism behind the reaction and recommendations on diagnosis/treatment are now published. Medscape talks to experts on how this may affect use of the vaccine.

www.medscape.com

 

[Robin]

And not surprisingly, the same clotting thing is being found with the Johnson and Johnson.

 

[Bruce Stephens]

And not surprisingly, the same clotting thing is being found with the Johnson and Johnson.

According to the article (I think) they're not sure it's the same yet.

(It interestingly also suggests that the apparent extra risk for younger patients might just be that the clots are more surprising in younger people. The risk comparison applies regardless: infection is vastly more dangerous for older people so even if the risk from these clots is about the same for older people the vaccine's still going to be more valuable.)

 

[Robin]

. The risk comparison applies regardless: infection is vastly more dangerous for older people so even if the risk from these clots is about the same for older people the vaccine's still going to be more valuable.)

I agree, but it hasn’t stopped Johnson and Johnson postponing their European rollout, so more delays likely in getting people jabbed.

 

[mikeyB]

Don't worry Robin, the Moderna vaccine is coming rapidly onstream, so that will pick up the slack in this country. Until, of course, somebody gets clotted.

The pity about the J&J vaccine is that it's just one shot, so ideal for countries with widespread populations far from healthcare.