[LINK] Accidental intravenous injection of AstraZenica as potential mechanism for post-vaccination TTS.

[Kim Holburn]

https://www.biorxiv.org/content/10.1101/2021.06.29.450356v1.abstract

Thrombocytopenia and splenic platelet directed immune responses after intravenous ChAdOx1 nCov-19 administration.

> Vaccines against SARS-CoV-2 are based on a range of novel vaccine platforms, with adenovirus-based approaches (like ChAdOx1 
> nCov-19) being one of them. Recently a rare and novel complication of SARS-CoV-2 targeted adenovirus vaccines has emerged: 
> thrombosis with thrombocytopenia syndrome (TTS). TTS is characterized by low platelet counts, clot formation at unusual anatomic 
> sites and platelet-activating PF4-polyanion antibodies reminiscent of heparin-induced thrombocytopenia. Here, we employ /in vitro/ 
> and /in vivo/ models to characterize the possible mechanisms of this platelet-targeted autoimmunity. We show that intravenous but 
> not intramuscular injection of ChAdOx1 nCov-19 triggers platelet-adenovirus aggregate formation and platelet activation. After 
> intravenous injection, these aggregates are phagocytosed by macrophages in the spleen and platelet remnants are found in the 
> marginal zone and follicles. This is followed by a pronounced B-cell response with the emergence of circulating antibodies binding 
> to platelets. Our work contributes to the understanding of TTS and highlights accidental intravenous injection as potential 
> mechanism for post-vaccination TTS. Hence, safe intramuscular injection, with aspiration prior to injection, could be a potential 
> preventive measure when administering adenovirus-based vaccines.

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Kim Holburn
IT Network & Security Consultant
+61 404072753
mailto:kim at holburn.net  aim://kimholburn
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