I've used windows since it first appeared thru Win95, now Win7 and there is always the risk of virus attacks even with paid virus protection software.
I've used Linux since Slackware was first introduced ... but have been an Ubuntu user for many years and have NEVER had even the hint of a virus and as far as I know, no one I am in communication with that uses Linux has ever seen a virus either.
I personally think about the only risk to Linux users is just plain basic system security common sense. Don't all root login via ssh, keep your password safe & use good passwords etc... which of course are the same things you'd do with Windows.
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