Pretty sure it's enviormental she's just exposed to a lot of germs.....I have only had one cold in the past three years......I just got over it..... But I don't get sick often with colds.maybe. I haven't gotten sick nearly as often since I moved from the elementary school to the high school.
I do get my shares and maybe a little more than my share of stomach bugs though.
Which is good.... Because with my asthma and COPD they about kill me.
Also i noticed since I retired I'm almost never sick at all. Just not exposed to as much... No touching germy steering wheels.... Not making that nightly stop at the grocery store touching germy shopping carts.... etc.
The first five years after my BMT my immune system was so weak I caught everything.... But since then it's been pretty normal. With one exception I get infections real easy and bad ones..... I've come close to losing body parts more than once.... Hands, toes, fingers.