I think most people catch it from a kid who was sick. 99% of the people I know caught it from a sick child. It's RARE that I meet someone who has no clue where it came from. It's always 'my niece was sick' or 'I was holding my friend's baby and thought he was better'. That's my experience at least! I never catch it (thankfully) but my kids have brought it home from school. My hubby has caught it from them. Oh wait! Once we went to a consignment sale and I let my kids play with the toys. They were both playing with a train table and got sick a few days later at the same time. So, that time it was a random event, but again, they had been playing with an item that I am sure a sick child had handled. I think it's the same in offices. Someone with a sick kid at home feels the need to share, etc. Can you tell I find kids (even my own) to be gross germ carriers?