systems that I know of (been using computers since 1988, or was it 1989)
is immune to it. I've used Windows-3.1 to XP. I used Macs for 6 months
at work and in that time yes it got infected.
On the other hand I started using Linux in 2006 (March, it was a
birthday gift) at home, mostly as a hobby at the start. I am now using
Linux at home, in my laptop, and at work. Not once did I have a problem
with malware. I don't miss it. I remember how paranoid I was when it
comes to virus in the Windows machines.
Maybe I got smarter as a user. I got wiser as I got older perhaps. I
know that malware for the Windows PC is in the thousands. There's none
for Linux, in the wild at least. Eventually, when Linux distros get a
market share above the 10 percentile maybe an enterprising hacker might
be interested to code a virus that can force it to its knees, who knows?