The three main types of viral hepatitis differ in how they spread, how they affect the liver, whether they are likely to become chronic, and whether there are vaccines to prevent them. Here are the details on each.
U.S. STATISTICS: About 2,000 cases a year.
HOW TRANSMITTED: Fecal matter from an infected person contaminating food or water.
COMMENT: Usually causes mild to moderate symptoms lasting several weeks; often no symptoms. Most people recover completely without treatment. Rarely causes liver failure or death. Confers lifelong immunity. Vaccination has dramatically reduced infections in the U.S., but risk remains high when traveling in developing countries.
U.S. STATISTICS: About 850,000 people have chronic infection, with about 3,000 new acute infections each year.
CHRONIC: 5 to 10 percent of infected people over age 5.
HOW TRANSMITTED: Blood, semen, and other body fluids, usually via unprotected sex or shared needles or cocaine straws. Also mother to fetus.
COMMENT: Acute symptoms, when they occur, are generally mild. People with chronic infection often remain asymptomatic until they develop cirrhosis or liver cancer. Vaccination, screening of donated blood, and testing of high-risk people have dramatically reduced infections in the U.S. Antiviral drugs can usually cure the infection.
U.S. STATISTICS: About 3.2 million people have chronic infection, including 1 in 30 baby boomers. Hepatitis C-related liver disease causes about 17,000 deaths annually. After dropping dramatically between 2000 and 2005, new acute infections have more than doubled since then to an estimated 3,000 acute cases a year (mostly ages 20 to 40), because of increases in injection-drug use.
CHRONIC: 80 percent of cases.
HOW TRANSMITTED: Blood, usually via transfusions before 1992 or shared needles or cocaine straws. Sexual transmission rare, but risk rises with multiple partners or concomitant HIV infection.
COMMENT: Only about 25 percent of newly infected people develop acute symptoms. At least half of people with chronic infection don’t know it because it can take decades for signs or symptoms to develop, at which point liver damage can be severe. About 5 to 20 percent develop cirrhosis or liver cancer. The leading cause for liver transplants in U.S., chronic infection also increases the risk of diabetes and cardiovascular disease and can ultimately damage many other organs.
New antiviral medications can now cure hepatitis C with few adverse effects. While “treating all infected persons is cost-effective from a societal perspective, the price of current medications is a formidable barrier for many,” according to an editorial by CDC researchers in the New England Journal of Medicine. Health insurers, including some state Medicaid programs, have restricted coverage to only patients with severe liver disease. It’s hoped that wider use of these drugs, combined with wider screening, will turn the tide against the disease.
Originally published April 2016, updated May 2019.