Oxford-AstraZeneca ChAdOx1 COVID-19 Vaccine Does Not Alter Platelet Aggregation

Abstract

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ChAdOx1 vaccination, blood coagulation, and inflammation: No effect on coagulation but increased interleukin‐6

“…Also, not all possibilities for immediate blood coagulation activation were assessed, such as platelet aggregation, which was not altered in previous literature. 20 In conclusion, the current study found no evidence of immediate activation of the blood coagulation system 1-2 days following ChAdOx1 vaccination. ChAdOx1 leads to an inflammatory response with increased levels of IL-6, as seen previously with other types of vaccinations.…”

Maintenance of Antibody Response in Egyptian Healthcare Workers Vaccinated with ChAdOx1 nCoV-19 Vaccine during Delta and Omicron Variants Pandemic: A Prospective Study

“…Following that, several cases of thrombotic events accompanied by thrombocytopenia have been observed and linked to the administration of the Oxford–AstraZeneca vaccine; Denmark, pursued by several European countries, was the first country to suspend the use of the Oxford–AstraZeneca vaccine [ 20 ]. Nevertheless, research data could not recognize platelet dysfunction in Oxford–AstraZeneca vaccinated population [ 21 , 22 ]. Therefore, the WHO and the European Medicines Agency declared that the trend of hypercoagulability could not be vindicated and recommended continued vaccination by the Oxford–AstraZeneca vaccine [ 23 ].…”

Anti‐severe acute respiratory syndrome coronavirus‐2 adenoviral‐vector vaccines trigger subclinical antiplatelet autoimmunity and increase of soluble platelet activation markers

“…Some studies have explored the effect of ChAdOx1 administration on anti‐PF4 antibody positivity, reporting that in 1.2%–8% of vaccinated subjects anti‐PF4 antibodies were found, but always at a low titre and in no case inducing platelet activation 11,13–15 . Two other studies reported that ChAdOx1 vaccine administration did not induce hypercoagulability and did not alter platelet aggregation compared to unvaccinated controls 16,17 . One recent study, instead, reported that both ChAdOx1 and BNT162b2 enhance inflammation and platelet activation in healthy subjects, although in a more marked way for ChAdOx1 18 …”

“…11,[13][14][15] Two other studies reported that ChAdOx1 vaccine administration did not induce hypercoagulability and did not alter platelet aggregation compared to unvaccinated controls. 16,17 One recent study, instead, reported that both ChAdOx1 and BNT162b2 enhance inflammation and platelet activation in healthy subjects, although in a more marked way for ChAdOx1. 18 However, to date no studies have assessed whether an immunological response involving platelets develops in healthy subjects after adenoviral-vector or mRNA-based vaccine administration and if this associates with platelet activation.…”