Here's a little fact for you all.

EVerytime a cold seems to go around, what it is doing is mutating the viral nucleic acids and genetic code ever so slightly everytime it breeds, therefore if I got a cold, spread it to 5,000 people then got it back again, it would not be the same strain as when I first coughed it out.
Also, few people can catch a cold off me, but those who do would then change the cold code which then makes other people susceptible to it. Which is why, in some families certain illnesses may go in order everytime, i.e. in mine it is mum - brother - me - dad. Or dad - me - brother - mum. I do not catch anything from my mum, neither my brother from my dad, and neither my mum and dad catch things from each other.

Strange world we live in really.

But I agree with Liz, not everyone has the luxury to be ill and have time off work. I had to use my sick days looking after my sick children when I worked, thus when I was practically crawling on the floor I still had to go into work.