Egads, I did interferon treatment and if it weren't for medicinal pot brownies, I'd never had made it ! My hepatologist had no problem with my using pot, "whatever it takes to get me through treatment", was his advice.
Relax.It does not affect your SVR at all.
Marijuana is not listed as interacting with Harvoni on Gilead prescribing information but you should ask your doctor to be certain :)
http://www.gilead.com/~/media/Files/pdfs/medicines/liver-disease/harvoni/harvoni_pi.pdf
If you think it might affect the outcome of you keeping your UND until you get an SVR, don't do it until you're completely done with tx. Can you imagine if you smoked and the following week or so you weren't UND anymore? That's right, you would think the weed affected your outcome.lol You can wait, the weed and the way it makes you feel aren't going anywhere. Take an idea from Nancy Reagan, just say no! :)