According to Davey Winder (PC Pro Magazine, security consultant) YES.
Android is another matter all together though as malware on Android is developing rapidly and having a security product installed on an android device is rapidly becoming essential.
Davey suggests that there is no need to install antivirus on a ‘standard’ ipad – not least because all apps all go through the App store.
‘jailbroken’ ipads are less secure of course but it’s unlikely that a virus will affect a whole machine because each app is ‘sandboxed’.
The downside is that no R&D is going into iOS so if a vulnerability is exploited there won’t be a fix for a long time.