Hi @mpbraendle,
There is a ClamAV plugin for OJS, written and maintained by the University of Pittsburgh; the github page is here:
It’s already in the Plugin Gallery but does not have wide compatibility with different versions of OJS. I believe they’re in the process of upgrading their plugins for newer releases of OJS but you’d need to ask them for details.
Regards,
Alec Smecher
Public Knowledge Project Team