From Ars Technica:
Former Firefox developer Robert O'Callahan, now a free agent and safe from the PR tentacles of his corporate overlord, says that antivirus software is terrible, AV vendors are terrible, and that you should uninstall your antivirus software immediately—unless you use Microsoft's Windows Defender, which is apparently okay.
This has long been my personal policy. More often than not, antivirus software causes more problems than it fixes. It's either an impediment to user activities, or a drain on system resources; most likely it is both. I haven't installed an anti-virus package on a Windows machine in over a decade (though I generally allow Windows Defender to continue to function.) I certainly haven't used a Mac antivirus in the OS X era.
Just practice smart computing. Don't download software from shady websites. Don't click on links you receive in your email (even if it says it's from your bank or your dad or the exiled Crown Prince of Nambutu.) Keep your computer's software, especially your web browser, up-to-date at all times.