Well it seems that due to the earlier release of SP2013 than many vendors expected, at the moment there is only one anti-virus vendor that supports SharePoint 2013 other than Microsoft – ESET.  ESET’s product also is only Beta – so this isn’t really ideal for production usage just yet.

Microsoft of course have ForeFront Protection for SharePoint 2010 however the whole ForeFront product line has been discontinued, so you cannot buy it.  If you have an Enterprise Agreement, and want to get it – perhaps speak with your Microsoft Account Manager and they may be able to help you out, depending on your agreement and when you speak with them.  If you do already have it, you’ll be supported until 31st December 2015 and receive anti-virus definition updates until then. From that point onward, you’ll need to migrate to another product. This was flagged by Spencer Harbar here.

You can also read Spencer’s sumamry of anti-virus products and their compatibility & supportability with SP2013.