The data I've looked at from WHO would suggest—I'm going to say this so carefully—that it's not due to COVID. Because of the huge numbers of COVID disease even in children, if this were really related to COVID, we should see it.
I want to turn that 90 degrees to say that some people and some researchers are suggesting that this may be co-infection: infection with perhaps an enteric adenovirus. I don't mean the kind that's in the vaccine, but an adenovirus that you would get in your GI tract. It may then get tipped over because of the circumstances, which might be related to COVID and might be related to other infections that are going on.
It's going to take another year, probably, before we're really going to understand it—I'm hopeful that it will be understood before that—but let me give you a parallel. There's a disease called “Kawasaki disease” that we know has to be related in some way to infection. We've been looking for 30 years to find out what it's all about, and we don't know yet.