Science (2021)

Blood (2021)

The occurrence of unusual blood clots has been associated with the adenoviral vector-based COVID-19 vaccines. Research published in Science and Blood supports a cause for this thrombosis is an antibody-mediated response to complexes formed between the adenovirus and platelet factor 4 (PF4). In the Science paper, the researchers used cryo-electron microscopy to show the highest resolution capsid structure so far of the viral vector ChAdOx1 and then used computational models and surface plasmon resonance to show a binding mechanism between PF4 and the adenoviral vectors used in COVID-19 vaccines. Meanwhile, the Blood paper shows that antibodies bind to this complex, and this results in platelet activation. These findings might enable tweaks to the viral vector vaccines to avoid such adverse events in the future.