UF-Led National Study Reveals Most Common Hepatitis C Strain In U.S. Is Most Difficult To Treat

August 1, 1996

GAINESVILLE—The most common strain of chronic hepatitis C in the United States is also the most difficult to treat, according to the largest survey ever conducted of patients with the life-threatening liver disease.

Prior to the study, physicians did not know that the failure of some patients to respond to traditional drug treatments was linked to the strain of hepatitis C infecting them, said Dr. Gary Davis, professor of medicine and director of the section of hepatobiliary disease at the University of Florida College of Medicine.

Among the six types of hepatitis C, type 1 is the most common among Americans, accounting for three-quarters of all cases, report UF researchers in the June issue of the Annals of Internal Medicine.

“Unfortunately, type 1 is the type that is associated with poor long-term response to interferon-alpha therapy, the drug physicians usually use to treat hepatitis C,” said Dr. Johnson Lau, associate professor of medicine at UF’s College of Medicine. “This highlights the importance of developing new treatments, which are urgently needed. Our center is making progress in developing new antiviral therapies in patients with chronic hepatitis C.”

An estimated 3.9 million U.S. residents are chronically infected with the disease, which is caused by a virus that sparks inflammation and can lead to liver failure, according to the Atlanta-based Centers for Disease Control. Infection with hepatitis C is the most common cause of chronic liver disease and the main reason for liver transplant in this country.

While once typically transmitted through blood transfusions and blood products, blood banks now screen for the hepatitis virus. But because the disease can progress slowly, newly diagnosed patients may have contracted the virus from a blood transfusion received years ago. A growing number are intravenous drug users who shared dirty needles or health-care workers who accidentally stuck themselves with a contaminated needle after treating a patient in the emergency room, for example.

Researchers from 10 medical centers across the nation participated in the survey of 438 U.S. patients with hepatitis C. Of six types in existence, types 1, 2 and 3 are most common in the United States, accounting for 91 percent of all cases.

UF medical researchers led the study, which also included participation by the University of Miami, the University of Southern California and the University of Colorado.

“Hepatitis C is a pretty significant problem,” Davis said. “It’s an infection that, when you get it, almost always persists. Other forms of hepatitis tend to go away. But hepatitis C becomes chronic, almost without exception, after a person is exposed to.”

Davis said UF researchers are continuing to study how the immune system responds to the virus and why it can’t get rid of it. They also are studying interferon in combination with other drugs to better treat the infection, as well as the development of new antiviral compounds to fight the disease.