WM97/CopyMe-A is a Word macro virus that has two methods of infecting documents.
If the document already contains a macro with a 'Document_Open' subroutine, then the virus will infect by inserting a 'CopyMe' subroutine into the existing module.
If the document does not contain a suitable macro, then the virus will infect by the more normal route of creating its own - in this case a 'ThisDocument' module.