No doctor or expert. But I did follow the AZ story. I understood, that Covid can cause blood cloths. A vaccine triggers an immune reaction, in that case Covid, so a particularly strong immune reaction, maybe together with a preposition of developing blood clots, can be a reason. Not sure if we know already what causes these side effects with AZ an JJ.

From a risk perspective, I wouldn't restrict either vaccine. But since we can easily use Moderna and BiontechPfizer instead for the most at risk groups it doesn't really change things, does it?