> They are very similar, but if you have the data from both set you can clearly see the difference.

It depends also on case by case basis, however long COVID is diagnosed in some patients with/as vaccination side effect. Even if it might be possible that these can be clearly differentiated, it's not done. It is also not that clearly defined and therefore overlaps with some other syndroms like fibromyalgia, which might be a confounding factor as well.