By the time I finished medical school in 1976, “non A, non B hepatitis” was a fairly common diagnosis after a blood transfusion. Twenty years later, they discovered the culprit, named it “hepatitis C,” and finally had a way to test for the virus in transfused blood. This reduced the risk of blood transfusion-associated hepatitis in the U.S. from 30% in 1970 to virtually zero in 2000.
However, every year, about 10,000 Americans still die from hepatitis C. In the world, about 150 million people are infected. In the USA, much of the infection is due to intravenous drug use, while in the developing world, contaminated blood transfusions are still the culprit. Egypt has a very high rate of hepatitis C infection (>20%) due to a failed mass-treatment campaign for a parasitic disease (snail fever), using improperly cleaned syringes.