I suspect they won't find an infectious agent in the liver specimens themselves. We see fulminant hepatitis, often requiring transplant, for unestablished reasons regularly, though never in such a surge as has happened recently. Suspect these are probably all variations of immune dysfunction, where the inciting virus has probably "long gone" (at least in terms of meaningful active infection).
Another suggestion has been that this is a variant of MIS-C, which typically happens six weeks post COVID. While multi-system, it's gut-centred and may represent either privileged site viral persistence or perhaps microbiome upset and subsequent uncontrolled inflammation. Liver is next in line from gut via portal blood flow, so potentially a reduction of mucosal integrity could lead to bad proteins/debris reaching gut blood without necessarily causing overt gut symptoms, but then inciting destructive immune cell activity in the liver.
I hope they can do due diligence here as this could answer questions that have eluded us for years. There does seem to be a political reluctance to entertain that this might be due to uncontrolled COVID infection in unprotected children. Many of us have been warning against the "let it rip" policies vocally, but have been overcome by minimising voices speaking bad science to those only too happy to listen. (Dr Gurdasani, as in the above tweets, has been beyond admirable through all of this, facing misogyny and racism, in lieu of valid scientific counter-arguments).
