I'm sure I have said this before but when my son was a baby he went to a nursery, and as @thistledo says caught every bug going around. Colds, ear infections (the absolute worst), foot & mouth, stomach bugs, the lot. We burned through a lot of annual leave taking time off with him when the nursery sent him home.
Now, he just doesn't get ill. Everyone else in the house can catch a cold and he'll be the one who doesn't. In fact this happened just a couple of weeks ago. He is in fifth year of high school now and hasn't missed a single day of high school through illness.
My only advice for @Dons_1988 - calpol and the ibuprofen version. Every 2 hours, alternate what you give the wee one. And when it is the inevitable ear infection, do not take the kid outside at all. A wee gust of wind and the baby will scream like you can't believe.