To add to this thread:

If you can't get ahold of fresh elderberry's, then Gaia of Herbs brand is the next best thing.

Along with a good vitamin d supplement, those 2 seem to have been the most effective at knocking out the flu I had over a weekend.
I did use other supplements and rememdies like sovereign silver, vitamin c, iosol iodine, multivitamin, fossil shell flour, apple cider vinegar, curamin, olive oil, etc

I hope this helps to compliment anyone's arsenal of natural medicines.