I see what you mean about the sick record. I never thought about it that way.
On the other hand, there are people that get sick all the time. Not play-sick, but actually sick, and are top performers. Given that fact, your future employer won't not hire you just because you have a poor immune system. They'd hire you because despite the fact that you get sick, you're still a good performer. Right?
So for me, the trick is to get the job done (As Donald Tsang would say
). I take sick leaves when I don't feel like coming in, but as long as I stay on top of my work, my boss is ok with it. I know it's hard to find a good job like this, and not everyone will like it, but its cool for me. =P