My little girl only had checkups before kindergarden. Not a single cold previous. Her kindergarden year she missed 23 days of school and went to the doctor a dozen times. She was constantly sick. This year has been beter, but no less sickness, just not to a debilitating degree. Everything she has, we get.
The problem, i think, is society. Parents have structured care for their children, and a sick day throws a wrench in it. Instead, then, of having to find a sitter or missing work, they send them to school to snot on their classmates. When i go to eat lunch with my daughter (now 1st grade) almost everyone in her glass is wheezing and expectorating like little germ bazookas. They drink and eat after each other, and they never seem to be urged to wash their hands. It's 'Lord of the Flies' meets 'The Hot Zone'.
I'm hoping by 3rd grade they will have built up some resistance...