Health.com recently ran an article that gives us a great insight to an age old question.  How long are you contagious after you've been sick?

In general, the period where people are most contagious is 5 to 7 days after their symptoms started.  But even if you adhere to this theory you're not totally in the clear.

Because doctors say you can still be contagious 2 weeks after your symptoms start.  And just because you feel better doesn't mean you're actually "better".

If you have children or live with several family members it can be like playing "Cold Olympics" as I have dubbed it.  My daughter Khloe was sick 4 days ago and she is finally getting over the crud.  Last night my son Elijah started to have a fever and this morning he was burning up.  So the Keith family is in full sprint in the "Cold Olympics" relay race.  Hopefully I don't have the next leg.

It usually takes 2 to 3 days to develop symptoms after you've been exposed to a virus.  So if you're around a bunch of sick family members during Christmas holiday and start sniffling the following day, it's probably not their fault.