According to the Centers for Disease Control and Prevention (CDC), hepatitis C (HCV) now kills more Americans than HIV/AIDS-related complications. By reviewing mortality rates from 1999 to 2007, researchers determined that HCV caused the death of 15,000 people, compared to the 13,000 deaths attributed to HIV over the same period.

In many cases, HCV went undetected for a very long time, taking years to slowly take over the liver of the infected.

HealthDay reported:

"These data underscore the urgent need to address the health threat posed by chronic hepatitis B and C in the United States," said investigator Dr. Scott Holmberg, chief of the Epidemiology and Surveillance Branch in CDC's Division of Viral Hepatitis.

About 3.2 million Americans are infected with hepatitis C, a major cause of liver cancer and cirrhosis, the CDC authors said. An estimated one-half to three-quarters of infected adults are unaware they have the disease, which progresses slowly.

Hepatitis C is spread through injection drug use, from blood transfusions received before routine blood-screening began in 1992, and through sexual contact. In some cases, it passes from mothers to infants.

HCV can stay hidden in the liver for decades, showing little or no symptoms until it has progressed to its late stages. HealthDay added:

"Seventy-three percent of hepatitis C deaths were reported among those 45 to 64 years old," Holmberg said. "As the population living with hepatitis C in the United States -- 66 percent of whom were born between 1945 and 1964 -- has aged and entered a high-risk period of life for hepatitis C-related disease, deaths associated with hepatitis C have increased substantially."

Learn more about hepatitis C treatment here.

Learn more about living with both HIV and hepatitis here.