Will avast implement Microsoft Antivirus API?
Microsoft Antivirus API enables software developers to develop applications that scan Microsoft Office documents before opening them. The Antivirus API also supports scanning Microsoft IE code downloads, such as ActiveX controls.
You can check that avast is not listed on Microsoft Office applications:
On the Menu Tools > Macro > Security
You can see, if you used sometime, TrendMicro, Inc.
F-Secure Client Security and Symantec AntiVirus were not implemented too...