Mid 2013 macbook air running BigSur 11.6.3 has a worm? Suggested virus protection?

Welcome to the Apple Support Communities.

HP is trying to sell you software out of fear. If Malwarebytes found nothing, you're good.

Mac computers do not need any sort of anti-virus, cleaners, VPNs, etc. The only thing they are good at is creating false marketing promises and taking consumers' money. In fact, anti-virus and other cleaners cause performance issues, security issues, and make macOS appear buggy. Your Mac is far worse with these types of Apps installed.

Mac computers have protection built-in, which is the best protection for your Mac. For specifics on macOS Security, see: macOS - Security - Apple and Protecting against malware in macOS - Apple Support. Mac computers also have built-in storage recommendations: Optimize storage space on your Mac - Apple Support. You can even use the built-in macOS Firewall: Block connections to your Mac with a firewall - Apple Support. Other than that, all you should do is restart your Mac approximately once a week and keep macOS up to date: Update macOS on Mac - Apple Support. 

Malwarebytes is the only exception to the above.

Jack

Intermittent issue printing from HP printer diagnosed by HP as a worm in my network for which they wanted to sell me virus protection for my network.

That's a load of bravo sierra. There is no such thing.

Shame on HP. I find it hard to believe you actually spoke to an HP representative, but nothing surprises me these days. If that's true that person should be summarily fired, and you deserve an apology from HP's CEO... whoever that happens to be these days. Since HP no longer makes any products worth buying, I can only assume they're turning their attention to even more worthless "virus protection".

Going down that road just wasted your time. Since that question is now behind you, perhaps you should describe what the problem is.

But I was troubled by the insistence that the “worm” was out to destroy my entire network, which is why I contacted Apple, who sent me to this forum.

Anyone would be troubled by that. Of course it's utter nonsense. For "nonsense" I encourage you to substitute a more accurate yet unprintable description. Unbelievable.

Updated drivers were undoubtedly the solution. Good to know Apple sent you here.