In the mid 1970s, Harvey J. Alter, Chief of the Infectious Disease Section in the Department of Transfusion Medicine at the National Institutes of Health, and his research team demonstrated how most post transfusion hepatitis cases were not due to hepatitis A or B viruses. Despite this discovery, international research efforts to identify the virus, initially called non-A, non-B hepatitis (NANBH), failed for the next decade. In 1987, Michael Houghton, Qui-Lim Choo, and George Kuo at Chiron Corporation, collaborating with Dr. D.W. Bradley from CDC, used a novel molecular cloning approach to identify the unknown organism and develop a diagnostic test. In 1988, the virus was confirmed by Alter by verifying its presence in a panel of NANBH specimens. In April 1989, the discovery of the virus, renamed hepatitis C virus (HCV), was published in two articles in the journal Science. The discovery led to significant improvements in diagnosis and improved antiviral treatment.
Chiron filed for several patents on the virus and its diagnosis. A competing patent application by the CDC was dropped in 1990 after Chiron paid $1.9 million to the CDC and $337,500 to Bradley. In 1994, Bradley sued Chiron, seeking to invalidate the patent, have himself included as a coinventor, and receive damages and royalty income. He dropped the suit in 1998 after losing before an appeals court.
In 2000, Drs. Alter and Houghton were honored with the Lasker Award for Clinical Medical Research for "pioneering work leading to the discovery of the virus that causes hepatitis C and the development of screening methods that reduced the risk of blood transfusion-associated hepatitis in the U.S. from 30% in 1970 to virtually zero in 2000."
In 2004, Chiron held 100 patents in 20 countries related to hepatitis C, and had successfully sued many companies for infringement. Scientists and competitors have complained the company hinders the fight against hepatitis C by demanding too much money for its technology.