The current recommendation from the CDC is that every person in the US born from 1945 to 1965 be tested for hepatitis C.
and here: https://www.cdc.gov/hepatitis/hcv/index.htm
Hepatitis C is a virus. It's a bit mysterious, how people get it. It is blood borne, but many people with positive testing swear up and down that they have never used drugs, no transfusion, no cocaine, no, no, no. AND sometimes a person has been married to someone with hepatitis C and they don't have it. My personal suspicion is that it can be passed sexually but that some people are much more likely to get it than others. (The CDC website agrees.) Genetic vulnerability or stress vulnerability or both.
We used to find hepatitis C in patients who have isolated elevated liver tests, especially the ALT. The first question we ask is how much alcohol they drink. Cut back or if they deny alcohol, we do a hepatitis panel. Hepatitis A, B and C. Ok, we are up to hepatitis G that I know of, but the exotic ones are currently rare in the US.
Hepatitis B is the most infectious sexually, followed by HIV and then hepatitis C. Hepatitis A is the fecal-oral one (wash your hands with soap!) that is usually food transmitted. Hepatitis A is usually the one where people KNOW they've gotten it because they can get sick as snot, turn bright yellow, vomiting, diarrhea, etc! I had a bright yellow patient show up when I was a resident. I did a hepatitis panel and it turned out to be acute hepatitis C. I called the liver specialist and then was confused when they got all excited. It's rare to diagnose acute hepatitis B or C. Most people just act like a viral illness, a bit sick but they don't have the hyperbilirubinemia and don't turn yellow.
We vaccinate for hepatitis B in anyone high risk. Health care workers, travelers, people who work with homeless, with the incarcerated, with immigrants. I was vaccinated working at NIH in the 1980s and with the serum vaccine. It's not serum any more. Now we are vaccinating children, which I agree with.
We had treatment for hepatitis B before we had treatment for hepatitis C. For hepatitis C, we were using interferon, which made people really ill, they had to be on it for a year, and it only worked less than half the time. The CDC recommendation came when harvoni showed up: a treatment that works and is way less toxic. Harvoni was the first approved and now there are others.
I have diagnosed more people with hepatitis C (and one with B) since the guidelines came out. And sent them for treatment. The interesting thing is that they are telling me that they thought the hepatitis C was not giving any symptoms, until an annoying but non-lethal symptom went away by the end of successful treatment.
One woman had a leg rash for years, worked up by dermatology, treatment unsuccessful. I said maybe it was the hepatitis C. She told me that the gastroenterologist said that it was not a hepatitis C rash: but he was wrong. It resolved with treatment.
Another said that long term annoying diarrhea and right lower abdominal pain both resolved with treatment. This person is surprised and pleased.
One person complained of a cough from the harvoni, which was again pooh-poohed by the gastroenterologist. The cough went away when the harvoni was done.
One person had not seen a doctor in 20 years. This person turned out to have hepatitis C on the screen. The person said, "I was well until I saw you!" I said, "No, you just were undiagnosed." That is why we are screening.
Two people said that they had been told that they had hepatitis 15-20 years ago and "Don't worry about it." At that time we did not have a treatment for either hepatitis B or C. In fact, when I was in medical school in the late 1980s, there was no hepatitis C. It was still called "non A, non B hepatitis". Medicine changes, the guidelines change, the treatment changes. In 1995, liver failure was one of the top ten causes of death in the US, along with HIV. They have fallen out of the top ten, replaced by renal (kidney) failure and dementia.
Medicine changes. Get screened if you are in the age group. It might heal something unexpected and it reduces your chances of liver cancer and cirrhosis and early death.
Mayo Clinic for short and clear: http://www.mayoclinic.org/diseases-conditions/hepatitis-c/home/ovc-20207365