> Elimination means 0%.

Not in this context, no. It means the same thing as being cured of Hep C means... there's a little bit still lingering around, but the systems that keep it under control mean that it doesn't cause any problems. The world and one's body are environments that are way too large to get rid of 100% of something without utterly obliterating them.

> That virus existed way before drug users did.

I'm skeptical. Living things have been drug users for approximately forever.

Anyway, a fun fact that I learned when I was getting my Hep C diagnosis and treatment is that the three most common ways to get it are

1) Be an IV drug user who's not extremely careful about their needles

2) Share your toothbrush with someone else

3) Have had a blood transfusion prior to ~1992, when they started screening the blood supply for Hep C

It turns out that -for the sex-havers that aren't into blood play- sex is one of the least effective methods of Hepatitis transmission.