Macs are immune to PC viruses. Currently no significant Mac viruses are in circulation; hackers tend to target the Windows operating system due to the sheer number of PC users. On their website, Apple claims the Mac is highly secure right out of the box, that it screens every file you download, and that it provides security updates to quickly address any potential security threat.

On the Other: Security Threats Do Exist

Viruses that affect Macs do exist, but because fewer users have Macs, hackers tend to focus on Windows viruses. As Macs become more popular, more viruses may be created. And, although Macs may be safe from most viruses, they can be compromised by Trojan horses and phishing attacks. Both of these require the user to download an infected file or enter information at an insecure site. Virus software may help avoid these threats.

Bottom Line

Virus protection is not needed on a Mac, although having it may offer certainty and peace of mind. Being cautious when surfing the web is the best protection you have against viruses. To negate the possibility of compromising the safety of your Mac computer, refrain from downloading unknown files and avoid insecure sites.

Source:

Washington Post: Anti-Virus On A Mac?

CNET: Mac Security Not So Much About the Mac

More Information:

Apple Computers