Flu vs. Cold vs. Nothing! Why do some get many colds and others never?

I always got the cold, the flu whatever it is... since I was a kid, especially as a kid, I'd get the flu often making me sick, bed bound with fever weakness and aches

Now I'm 31yrs old, male and things are better, i get the flu twice or 3 times a year.. even though my diet and health in general are much better. With the flue i get symptoms of aching all over, fever, weakness, sore throat, pain in chest, stuffy head, headaches, runny nose, sneezing etc..

I know some people that never get the flu, all they suffer is cold symptoms, even though we both lived together and likely share the same germs.

Why do I often get a full-blow flu while others just get colds or nothing?

Is this a sign that my immune system is weak and always has been? Or just that I have a sensitive respiratory system?

The people that dont get sick much or at all, do they have a stronger immune system? Or is their system weak that it does not fight back and thus they dont get any cold/flu symptoms? Tweet