This is my favorite immune product on the market.
MyCommunity is a 17 species, organic mushroom formula originally created by myco-warrior (and my personal hero) Paul Stamets. I have some patients who swear by this product and say they haven't gotten sick since using it regularly.
Use this daily, or double (or triple!) the dose for acute symptoms.
Other things you can do for immune health include: Getting lots of sleep, avoiding sweets, eating garlic, and laughing a lot. I suggest also keeping some remedies around in case you get sick, like Oscillocoinum and Immune Glycerite. Additionally, keep your skin and lymphatic system healthy with regular skin scrubbing.