Wouldn't this catch only those with the most severe sympthoms (the dreaded 20% often quoted, of which a part of that is fatal) and not the "dangerous" (because

Wouldn't this catch only those with the most severe sympthoms (the dreaded 20% often quoted, of which a part of that is fatal) and not the "dangerous" (because they can infect others more easily) people with mild to no sympthoms?