Just spitballing here, but it might be possible that these individuals have an immune system that is pre-disposed to an auto-immune attack on their platelets. I

Just spitballing here, but it might be possible that these individuals have an immune system that is pre-disposed to an auto-immune attack on their platelets. If so it might have happened eventually anyway (hence no deviation from normal stats), but the vaccine happens to trigger it pretty consistently. If so, and if the thrombosis turns out to be treatable like the German researchers think, then getting the AZ vaccine might turn out to be a relatively safe, controlled way for people with the condition to find out that they have it (compared to something else triggering it at some random time where they are not on the lookout for symptoms, and thus more likely to die from the blood clots). All theoretical at this point, but it would be a pretty good outcome if this side effect of the vaccine in reality turns out to become a screening method for a previously unknown condition.