While hepatitis C can be transmitted through sexual activity, that mode is very ineffective, says Bryce Smith, Lead Health Scientist for the CDC's Division of Viral Hepatitis who helped write the recommendations.
Whether sexual activity transmits Hepatitis C "could depend on the sexual practice," Smith says. "But sometimes it depends on other things (people) may be sharing around the house. Are they sharing a razor or a toothbrush? If there is an opportunity to share something that contains infected blood, that's a way that someone can become infected."
Prior to tighter infection control guidelines in healthcare settings issued subsequent to the HIV epidemic in the mid 1980s, acute and ambulatory care facilities may have been settings for transmission, for example, a patient who underwent a tonsillectomy decades ago.
That, in part, is why the CDC is issuing this much wider guideline for population testing Smith says.