OM ("OfficeMacro") is a family name for all Microsoft Office Macro viruses. These are viruses which infect not only one Office application but several - for example, Word and Excel.
For example, if you're looking for the description of "O97M/Jerk", "OfficeMacro.Jerk" or "Macro.Office.Jerk" virus, see the description of "Jerk".
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.