wellness for kids with lung issues

[puffingirl]

I know there are a bunch of mamas here with little ones with lung issues--breathing treatments at the smallest, little cold that blows up into a big deal.  I think we finally have a handle on getting the protocol rolling along quickly when she gets sick but we are really struggling with how often she is sick.  Since mid-October we have not gone more than 2 weeks without illness for her.  It's awful. When she gets sick it last soooo long and it seems like the time she is well goes so quickly. So, here's my question: How do you keep your kids well?  We hand wash/sanitize all the time, she eats well, sleeps well, we watch exposure to others, but she is still catching every single bug that goes around.  Are there any supplements or other things that you do that you feel like helps your LO's immunity?  BTW, DD is 3.5, if that matters.