On Friday, the World Health Organization (WHO) urged governments to attack the problem with more urgency, and more money.
Only about three million people from an estimated 71 million Hepatitis C virus (HCV) carriers, received the treatment they needed, the UN's health organ said at an International Liver Congress in Paris.
"We very much encourage leaders in countries and politicians, policymakers, to... include Hepatitis C treatment into their broader health portfolio and really also find the domestic resources that are needed to take this forward," said Gottfried Hirnschall, head of the WHO's global hepatitis programme.
The price of a cure ranges from about $200 (162 euros) to several thousand dollars per person -- excluding diagnostic tests and healthcare salaries and infrastructure.
But "by really frontloading and treating people, and treating them as quickly as possible... you save costs later," Hirnschall told AFP.
"You save costs that you have if somebody progresses to liver disease or other diseases that require hospitalisation, in some instances very costly liver transplants, (or) tertiary care."
There is no vaccine for Hepatitis C, and curing it is the best way to prevent virus spread.
HCV is most commonly passed on through infected blood -- either by soiled needles used to inject legal or illegal drugs, or blood transfusions.
Only about one in five people even know they are infected. Many go on to develop cancer or cirrhosis of the liver.