Is there any purpose to anti-virus?
Do you run anti-virus on workstations or servers? Is it worth the hassle?
Nope, just scareware. Use NoScript in browser, enable a firewall (eg. firewalld) and don't preview attachments in e-mails from unknown senders (unless your mail-provider provides proxy previews the attachments). Oh, and no reusing passwords.
https://support.google.com/a/answer/3299041?hl=en
Depends on your risk tolerance. Some entities can survive a single breached node, and some cannot. Those that have been breached, tend to be less tolerable (recency bias).