I wish I could remember the source, but degree of exposure matters. I suppose you could explain this as "flattening the curve" writ small, as the bodies defense

I wish I could remember the source, but degree of exposure matters. I suppose you could explain this as "flattening the curve" writ small, as the bodies defenses don't have time to build up. This is why healthcare workers can get sicker than ordinary folks, because they are swimming in virus.