So many caveats missing from this title and the article it feels like click bait. (It worked, I clicked). Are there per-existing conditions? What is the prevale

So many caveats missing from this title and the article it feels like click bait. (It worked, I clicked). Are there per-existing conditions? What is the prevalence of this effect? How long does this conditon last? It can’t be that frequent if it took 6 months to find enough cases. It’s like the Kawasaki-like syndrom in kids with COVID-19. It happens, but what is the prevalence? Just anecdata in the article and « we need more study »