How can my wife get the flu and I am fine? Or Vice-versa?

Question

I understand immunity but from my understanding, the influenza virus changes pretty quickly.

How can I be in close proximity to my wife and not catch a flu that puts her down for 3 days? Or when I get a flu where I feel like I’m dying she is fine?

In: Biology

Answer 1

There’s a lot of chance involved. Maybe you just never got enough of it in your system, by luck. Maybe your body developed enough immunity from the slight but constant exposure that you never got sick. It’s effectively random.