At the last count there have been 150,000 viruses written that attack the Microsoft Operating System. To date there has never been a real virus on the Apple OS. People have tried but failed. The Apple OS was completely rewritten in 2001 and is currently called OSX (ten). It comes with a built in Firewall. All istallation of applications are password protected which means it would be difficult for any rogue application to install itself. I do however scan for viruses just incase, but no, in fifteen years, I have never had one.