In the U.S. today, ProPublica and the Washington Post have jointly reported that the cost to treat hepatitis C for Medicare patients soared 15-fold last year, from 2013.

In 2014 Medicare spent $4.5 billion on hep C drugs. This doesn’t include deductibles that Medicare patients pay. Medicare is available to U.S. citizens and permanent residents over 65.

Solvadi, Olysio (Galexos in Canada), and Harvoni account for most of the programs’ spending. Medicaid, the U.S. program that funds health care for the poor, spent $1.2 billion on the drugs in the first nine months of 2014.

Given that many people were still getting interferon treatment through much of 2014, the 2015 costs could climb much higher. Competition, rationing, or compassion from drug companies could lower the costs, of course.