> You'll have almost no reports of "systemic circulating virus" load, because there's not really an accepted definition for how this measurement would be taken.

Wait, what? This seems completely at odds with the literal definition of viral load per https://en.wikipedia.org/wiki/Viral_load:

> Viral load, also known as viral burden, is a numerical expression of the quantity of virus in a given volume of fluid, including biological and environmental specimens.