This is a very detailed scientific study from experts in the field and provides further pieces to a jigsaw of understanding vaccine induced thrombocytopenia and thrombosis. It specifically helps to elucidate the most likely initial step in the process after the vaccine is administered – that negatively charged areas in the adenoviral vaccine can bind to platelet 4 (a component of a person’s first line of defence against infection).  If a person then develops antibodies against this platelet factor 4 complex, in some cases it can then lead to activation of blood platelets which can then result in the final consequences of low platelets and thrombosis. This study confirms previous hypothesis by demonstrating the actual location of binding of PF4 to the vaccine. The authors reasonably speculate that one might be able to modify future adenoviral based vaccines to avoid this unwanted rare untoward effect. Many questions still remain unanswered; including whether some people may be more susceptible than others and why the thrombosis is most commonly in the veins of the brain and liver but this may come with time and further research.