That was not intended to be even remotely racist on my part. My fiance is chinese, and the girl NEVER gets sick. And none of the indian students in my department do either.
I always assumed it was simply because of exposure. India and China are significantly more crowded than the US, so you are simply exposed to more stuff more often. I refer to it as her nuclear immune system.
And China at least is much less all about sterile surfaces compared to the US. I really do think it's weakened our immune systems over the years.
Edit: Wait, I'm american, so it's supposed to be nucular, isn't it?