michael adams submitted this idea :
So they wash/clean their hands how often ?

Every time they touch something ?

Otherwise what's the point ?

Or is the claim that frequent washing of the hands somehow
builds up immunity for future touches ?

Idea is if you have touched a suspect surface, make sure you wash your
hands before then touching any part of your face. The principle is one
of preventing germs from contact with surfaces, being transferred to
your eyes or mouth, where they then get easy access to your lungs.