Mac OS X, which has like a 100% more users than Windows Vista (because it's not out yet), has less viruses than Windows Vista. Ok, there is some example code that show how to write viruses for the new OS so I guess it's not a real virus yet.

A virus writer has published the first examples of malicious code that targets Microsoft's upcoming command-line shell, code-named Monad, according to Finnish antivirus maker F-Secure. If the technology is included in Windows Vista, these could be one of the first viruses to target the new operating system formerly known as Longhorn, F-Secure said Thursday.

How convenient that this came from a company that makes antivirus software? The same thing happened a while back whenn Intego ran around saying it had found a Mac OS X virus. Nothing ever came of that either. You have to consider the source. I have no doubt that considerable effort will be put into virus in Vista however.