Story highlights Sovaldi has been approved to treat chronic hepatitis C

About 3.2 million Americans are infected with the disease

Hepatitis C is the leading reason for liver transplantation in the U.S.

The U.S. Food and Drug Administration approved a breakthrough drug Friday to treat chronic hepatitis C virus infection.

Sovaldi (sofosbuvir) is the first drug that has been shown to safely and effectively treat certain types of hepatitis C infection without a need for interferon, the FDA said.

Hepatitis C is a viral disease that causes inflammation of the liver, which can lead to diminished liver function or liver failure. About 3.2 million Americans are infected with hepatitis C, according to the Centers for Disease Control and Prevention.

Sovaldi is the second drug that the FDA has approved in the past two weeks to treat chronic hepatitis C virus infection . Olysio (simeprevir) was approved on November 22.

Dr. John Ward, director of the Division of Viral Hepatitis at the CDC, in a statement called this a "landmark advance in the treatment of hepatitis C, opening up new opportunities to stop the spread of this virus and the ravages of this disease."

But new therapies only work if people actually receive treatment, he added.

"The potential of these and other treatment advances hinges entirely on our ability to get more people screened and into care," he said. "Right now, most Americans with hepatitis C don't access treatment because they have no idea they're infected."

Chronic hepatitis C infection can lead to long-term health problems and even death, according to the CDC. The virus is spread primarily when individuals have contact with the blood of someone who is infected.

Sharing needles or equipment to inject drugs is how most people who become infected acquire the disease.

The disease can also be spread through sexual contact, but the risk is believed to be low, according to the CDC . Sharing personal items such as razors or toothbrushes, which may have had contact with the blood of someone who is infected, is another less common risk.

It may take several years for symptoms to become apparent to individuals infected with hepatitis C. Most people with the disease have no symptoms until liver damage becomes apparent.

Symptoms may include fever, fatigue, loss of appetite, vomiting, nausea, abdominal pain, dark urine, clay-colored bowel movements, joint pain and jaundice, according to the CDC.

The disease is the most common cause of cirrhosis and liver cancer, and the leading reason for liver transplantation in the country, according to the CDC. Hepatitis C causes about 15,000 deaths each year in the United States.

The CDC urges all U.S. baby boomers, and others at risk, to get tested for hepatitis C.

"Widespread screening, together with new cures, promises to slash the burden of hepatitis C in this country and save thousands of lives," Ward said.