Hi there, my DS was picking up many colds earlier in the year when he started going to playgroup for the first time. After enduring several colds one after the other and throat infections etc I saw a naturopath for advice on building up his immune system. She gave me a probiotic from Metagenics called Flora Care for Kids. He hasn't been sick since we started this. Might be something to consider. If you have a health food store near you that has a Naturopath on staff they can probably get it for you. Good luck!