To date, there are no self-propagating viruses affecting macOS.
The malware and adware that can get on a Mac have to happen with the user's aid. As in, the user has to be actively involved in the installation of the malware or adware. It does not show up on its own. So running an anti-virus package 24 hours a day is a waste of system resources, shortens the battery life of your laptop, generates more heat, affects the performance of your Mac, etc...
NOTE: A user can be tricked into installing malware or adware. They go to a web page where they want to download an app, see a bright Green Download button, however, that button happens to be an Ad which downloads the malware or adware. Since the user was expecting to install something, they go through installing the malware or adware. This actually happened to my wife, who is a seasoned software developer.
Another way the user can be tricked is a download site will put their own installer around some freeware/shareware and the installer will do a side-load of adware, for which the download site gets paid. And it is also possible for a software developer to get paid to include an adware side-load when installing their app.
If you are not installing software from a source outside of the Applications -> App Store, then it is unlikely you are going to get malware or adware installed on your system, so save all your system performance for running your apps.
