Hepatitis C is the most common cause of liver disease in the United States. It frequently causes no symptoms and often goes undiagnosed. Recently, the Centers for Disease Control recommended testing for anyone with risk factors and all baby boomers (people born between 1945 and 1965).

About 3.2 million Americans are infected with hepatitis C. Eighty percent of infected patients go on to develop chronic liver disease. Consequently, hepatitis C is one of the leading causes of liver failure, and about 15,000 Americans die each year of consequences of the virus. In fact, more Americans now die of hepatitis C than of HIV.

The most common risk factors for hepatitis C are a blood transfusion before screening of the blood supply began (in June 1992) and intravenous drug use. Before screening, blood transfusions were a common mode of transmission of the hepatitis C virus, and as many as 250,000 transfusion-associated infections occurred each year. Since screening of the blood supply began, transfusion-associated hepatitis C has been virtually eliminated. It is estimated that less than one out of every 1 million units is contaminated, and there have been no documented cases of hepatitis C transmission via the blood supply in more than 10 years.

Currently, the most common risk factor is intravenous drug use. About one-third of young drug users (ages 18 to 30) are infected, and older and former drug users have infection rates of up to 90 percent, reflecting the increased risk of infection with longer or more prolonged use. Even a very brief period or one-time intravenous drug use puts one at risk.

Hepatitis C also can be transmitted sexually. However, sexual transmission is likely relatively rare. In studies of married, monogamous couples, only 1 to 3 percent passed hepatitis C from one partner to another. Hepatitis C also can be associated with nasal cocaine use or tattoos. Homemade or “jailhouse” tattoos are clearly of highest risk.

Unfortunately, many people with hepatitis C are not aware that they are infected. The disease is usually asymptomatic, and most infected patients will have no symptoms until late in the disease when their liver starts to fail. Some people will be detected with routine blood work when their liver function tests are found to be elevated. However, in many infected patients (even some who will eventually develop liver failure), these tests will be normal. Consequently, the most reliable way to detect infection is specifically to test for it.

Traditionally, testing has been recommended for anyone with risk factors: a history of intravenous drug use, a blood transfusion before screening began or anyone with a hepatitis C-positive sexual partner. Unfortunately, this “targeted testing” missed many infections because patients were either unaware of or did not admit that they were at risk.

The highest rate of hepatitis C transmission occurred in the 1970s and 1980s, when the rates of transmission by IV drug use were highest and the blood supply was not protected. Consequently, the highest rate of infections occurred among babies (those born between 1945 and 1965). It is estimated that 75 percent of those currently infected with hepatitis C were born between these years.

Therefore, the Centers for Disease Control recently recommended that all baby boomers have a one-time hepatitis C test. It is estimated that routine testing of baby boomers will uncover approximately 800,000 new infections.

Hepatitis C is common, frequently asymptomatic, and most infections will go undetected unless one specifically tests for the virus. It is recommended that anyone with active risk factors be tested regularly and all baby boomers have at least one lifetime test.

Dr. John Goldman is Program Director of Internal Medicine at PinnacleHealth.