"Over the past decade in the United States, 35 outbreaks of Hepatitis C have been linked to unsafe injection practices in healthcare facilities" I just read this on a Hepatitis C website. I read about the hospital in Colorado where a surgical tech was abusing injectable drugs and replacing the liquid with water so the multi-dose vial appeared to have enough medication. Investigators believed that this had been going on for 10 years and had the potential to effect hundreds, if not thousands of patients who had surgery there. I do know that some patients tested positive.
I also read a 6-part series written by Meg Heckman, who acquired the disease at birth by getting a tainted blood transfusion. The blood supply was unsafe in the U.S. until 1993, so anyone who received a transfusion prior to that date should be tested.
Here's a link to Meg's story, which is very well written and compelling:
http://www.concordmonitor.com/article/228639/infected-at-birth