I'm reminded of five minutes after take-off in an Iberia flight from Madrid to Santiago, the young woman with her child sat next to her, in the adjacent seats to me - turning to me and saying "by the way, have you had chicken pox".
I ban even my office staff from coming into work with a cold, because of the effect on everybody else - particularly the fliers. But it's irresponsible attitudes like that woman's that cause international pandemics.
One obvious statement - the cold may not be preventable, but do get an annual flu jab.
G