I’ve been a Mac user for almost 30 years. It took that long for me to get a virus!
And all it does is pop up every few hours and beeps ... no porn, no re-direction.
Technically, it's not a virus. It's just really nasty "helper" ware that does everything macOS already does for itself but wants to charge you to do it. . . and nag you about it. Thirty-seven state Attorney's General sued the publisher to force the publisher of MacKeeper to refund the money for their fraudulent sales practices, but they are back doing the exact same thing all over again.
You DO have to download and install it. In fact, Bunny, you have to buy it.
Are you certain you actually have it on your system or are you just seeing a pop-up advertising claiming your Mac is infected and you need to use MacKeeper of MacCLeaner to get rid of it? That ad is being spread by Google Ads on random websites. It has a script in the ad that takes over the entire website it is on and the only way to get our of it is to force quit Safari and restart Safari while holding down the Shift key to assure you don't open the same tab with that ad still there. This is actually Google's fault for allowing this advertising on their rotation.