Cold

Some of my friends have a cold, call in sick and staying home. Today I was talking to my co-worker about the cold. Seems like when I was living in Canada, I've never gotten any cold from my Canadian friends. And I know there's a couple who live together (Japanese and I think American) and they don't pass cold to each other. So I'm wondering if you have different background, then you get different kind of cold... sounds silly though that's what we talked about today at work. Yeah yeah, we didn't have anything better to do!