So, as far as I can tell there are two basic schools of thought. Either if one child gets sick in the family they are isolated so they don't spread the germs OR everyone gets exposed and gets over it all together. I don't like the idea of purposefully putting sick kids around well children very much. There was even a news blog about people having "swine flu parties" like they used to have for chicken pox way back when and how that is not a particularly great thing to be doing to your children. I can agree with that. But when a child gets the common cold, should you really try to keep the other children away, or is it just inevitable that everyone is going to get it anyway so you might as well all do it together?
Formerly, I used to try to keep the sick child apart. The last few illnesses we have had though, we all ended up getting the cold no matter what I did. We all know why. Because small children are basically just enormous walking drool balls. And you know if a child is sick, he/she will almost always "forget" to use a kleenex to sneeze into, instead sending droplets of germ infested drool/snot flying like little missles all around them (germ warfare comes to mind). Even the cutest, sweetest child makes disgusting mistakes like this occasionally when ill. So, point being, we all end up getting it anyway, only we take shifts. First the baby, then the toddler, then the older brother (mom is always in there somewhere too, though sometimes dad escapes). When taken in such shifts, the cold then always lasts around a month for an average family of 5. This makes life difficult for everyone. My personal opinion is that when stretched out like that the cold germ has time to gather defensive strategies and mutate so that about the time the last person is getting well, the new "strain" is just mounting its attack against the baby again. In this fashion colds can last for what seems like fffffffffffffffooooooooooorrrrrrrreeeeeeeevvvvvvvveeeeeeeeerrrrrrrrr..... So. I am still not sure. But it is interesting to consider.