The cost involved is getting rid of unwanted
>information. And as most information is noise and misinformation the latter
>of which the flu virus belongs, this means a high cost. The theory You
>refer to about usefulness of viruses is _very_ unproved.

What i am refering to is my experience and other eating instinctively  of"
silent "viral infection. The theory is coming after as an attempt to explain
the phenomena of asymptomatic viral infection.
If the virus is an unwanted noise ( who decide that ? the set up incubation
period suggest that the body doesn't) we would like to have
a proven explanation of why viruses are mostly silent and doesn't require
the effort to want to be rid of. The fact that viral infections in certain
conditions  ( ingestions of genetically unexpected molecules?) get out of
hands and can kill  doesn't make  ever a proven theory about the
harmfullness of
viruses.
Mostly , a car is not designed and used to kill but in certain situations
congested traffic, not paying attention to the regulating signs...) , it
does.
Same with viruses.
If i had to wait for the proven theories to navigate among the noisy
bakground of contradictory scientific theories, i will be dead by now.
jean-claude