See the question and my original answer on StackOverflow

The Quick Access virtual folder path, as a string, is shell:::{679f85cb-0220-4080-b29b-5540cc05aab6}, (this guid name is CLSID_HomeFolder).

So, you can force a refresh of all items under this virtual folder with a call to:

SHChangeNotify(SHCNE_UPDATEDIR, SHCNF_PATHW, L"shell:::{679f85cb-0220-4080-b29b-5540cc05aab6}", NULL);

If you want to refresh only a specific set of children, just get the PIDL or the path of these items and call SHChangeNotify(SHCNE_UPDATEITEM, ...) on each.