Yesterday's release included a new feature to let publishers know the status of uploaded files while they are scanned for viruses.
When publishers attach a file to a document, they will now see a message to let them know the file is being virus scanned. Reloading the attachments tab after virus check is complete (usually within a minute or two) will show whether the file contains a virus, as shown in this screenshot:
Previously, there was no notification of a file being quarantined by the virus checker - it would just not be available for users to download on the front end. There are only 4 documents in the system that consequently have quarantined (ie missing) file attachments. We have emailed the owners of these documents so they can re-upload the missing files.