[mlyle]

> However, I'm finding it hard to model a scenario in which a virus is already replicating in one's system and external exposure to comparitively infinitesimal amounts of the same virus has an impact. Do you have any actual evidence to present which backs up your claims?

Who really knows, but there are genetic diversity effects in other diseases. We also know that being exposed to a tiny initial viral load has a better prognosis with many diseases than a massive one (including with past SARS).

Doctors could be facing a "quadruple whammy"-- a disproportionate share of the worst strains (because they're meeting the most ill patients; exposure to greater viral loads; exposure to many patients with many slight variants of the disease; and sleep deprivation and overwork causing minor immune suppression.

But in the end, this is all speculation.