There was a long thread quite active for a while - "Avian Flu Preparedness Thread". There was a long discussion about the utility of elderberries. Maybe someone can dredge up a link or you can do a search. The problem with eldeberries is they stimulate the immune system (apparently) which may not be a good thing with this flu. Unless it can keep someone from getting the flu in the first place.
There are opinions all over the place on this.
Some of this discussion is covered in the thread that I linked in post #30.