Sol,

    I found that irrigating my sinus with CS once a week or right after 
exposure to someone who was sick prevented me from catching a cold or the flu.  
I haven't had one in three years.  Washing the hands is another preventative 
measure but I don't do that as often as I should.   Before I started using CS 
in the sinus I got 4-5 colds a year.

   Bob