Welcome to the forum. I’ll start by stressing that hepatitis C isn’t an STD. It has that reputation, but with one exception it’s an urban myth. The only proved sexual transmission is for anal sex in men having sex with men, and even then only when it involves trauma with bleeding. Vaginal sex (even during menstruation), oral sex, etc rarely transmit HCV. The lifelong heterosexual partners of infected persons have no higher frequency of HCV than people without such exposure, unless blood exposure also has occurred in those couples, e.g. shared needles.

In a way, that starts to answer your question. If even as intimate an exposure as intercourse doesn’t regularly transmit HCV, what could the transmission risk possibly be for non-sexual (entirely non-intimate) contact of the type you are concerned about? There is no risk from massage, hand-genital contact, etc, even when open wounds are involved. Can I guarantee it couldn’t happen? No. But if it can, it’s with a risk in the ballpark of being hit by lightning or a meteorite.

I don’t have much experience with HCV testing. For the reasons above, we have not routinely tested for it in my STD clinic or in people with other STDs, unless they have known blood exposure. (That’s changing in the past year or so – not because of elevated risk in people with STDs, but because new guidelines advise that everybody have an HCV test once, regardless of known risks.) That said, my understanding is that the window period for HCV antibody testing is 3 months. Antibiotics have no effect on the immune system or on the window period for HCV, HIV, or any other viral or blood borne infection.

In summary, combining a virtually zero risk exposure plus negative test results at 20 weeks, you can be 100% certain you have neither HCV nor HIV (assuming no true exposures since then).

I hope this has helped. Best wishes--  HHH, MD