My son has no detectible IgA and severe asthma. The best thing that we found is avoiding crowds as much as possible, taking echinacea, vitamin c, and a multivitamin. As you mentioned- also be sure to get your vaccinations. And finally, exercise regularly and eat your fruits and veggies.

You're going to get sick but as you get older things will improve. Unfortunately, exposure to colds will be the best way to build your immune system. My son was terribly sick for years but at the age of 21 he has now been exposed to most of the colds out there. It is now rare for him to be sick for more than a couple of days. It usually happens once every year or two.

Be sure to let your teachers know what's going on. My son's teachers were always good about extending deadlines during his illness, as long as he had a doctor's note. They're not as understanding in college. There's always one professor that gives him a hard time. There's always a disability office on campus. Bring a note to them from the doctor that outlines your diagnosis and how it affects you. It will provide you protection from that one grumpy professor if they give you a hard time.