An anti-virus for iOS?

For the time being, it’s not possible, and here's why.

Of course, impregnable systems don’t exist, and there are malicious programs for iOS too. However, so far, they are few and far between, and it’s rare to come across one. To be installed under iOS, an application has to be downloaded from Apple Store (except for jailbroken devices), and all the applications are verified before being uploaded by their developers into the store. This impedes malware from spreading significantly.

In addition, each user and each application has its own iOS sandbox, and they cannot reach anywhere beyond it. The memory area and files used by one application are inaccessible to other applications. This means that with the existing architecture, an anti-virus wouldn’t be able to scan other programs operating on a device or their corresponding files.