Good Question
All Mac in our house since 1992. I used to subscribe to one of the anti virus 'name brands' like Norton, IIRC. Then found out more about problems caused (!) by their product than any solutions claimed... It's been maybe 15 years since we've used any of those applications.
Other than a really irritating advertising piece of malware that sneaked into Safari a couple years ago, we have never suffered an attack on any version of the Mac OS itself.
Everyone I know with windows does have some sort of annual upgrade ($$) or regular subscription ($) defense against virus attacks. They all just shrug say that it's normal for computing and that my experiences do not count.
I guess that changing to a different OS is too traumatic for them to contemplate, altho I used to use Windows at work, starting with 3.1, and never found any difficulty with adapting either way. Actually, for a while my employer used IBM's own OS/2, which was much more stable and Mac-like, but then a salesperson from MS used either liquor or hypnosis to get them to change over to Windows.
Oh well, the Roman's probably had similar problems with the suppliers of spears and shields, too. And tunics and sandals!
Hope you get a useable answer.