OS X is nowhere near needing antivirus software, regardless of what features the OS X security team has managed to get added to the release.
Just another example of the difference between "safety" and "security". Houses in Kennilworth, IL need less security than houses in Rogers Park --- there are something like 192 police officers per Kennilworth township block --- and yet Kennilworth houses can be counted on to have state-of-the-art security, because they can, and state-of-the-art security is a selling point.