More people in the United States now die from hepatitis C each year than from AIDS, according to a new report from the Centers for Disease Control and Prevention. More than 3.2 million people are currently infected with hepatitis C.

Using data on more than 22 million deaths and their causes, researchers found that hepatitis C death rates increased to almost 5 per 100,000 people in 2007 from fewer than 3 per 100,000 in 1999. Over the same period, the H.I.V. death rate declined to a little more than 4 per 100,000 from more than 6 per 100,000.

There were 15,106 deaths due to hepatitis C in 2007, almost 75 percent of them among people ages 45 to 64. The report appears in the Feb. 21 issue of The Annals of Internal Medicine.

Dr. John W. Ward, director of the Division of Viral Hepatitis at the C.D.C. and an author of the study, said that there was now a treatment that was about 70 percent effective at clearing the virus from the body. But, he said, most infected people are unaware of their condition and do not receive treatment.