I’m not sure whether you’re arguing that this wouldn’t be noticed or if we cannot measure it statistically. For the former, the side effect is blot clots with

I’m not sure whether you’re arguing that this wouldn’t be noticed or if we cannot measure it statistically. For the former, the side effect is blot clots with thrombocytopenia. That combo is very rare, is indicative of an autoimmune etiology, and would stand out to healthcare providers and be reported. Even if there were a few cases that were not identified or reported, it would not lead to a 2x order of magnitude difference in the reported incidence as you suggest. If your argument is a statistical one about the study being underpowered, then show your math. Because this is definitely not a small n. Otherwise, be careful about presuming that something in a domain unfamiliar to you is equally unclear to experts in that domain.