Washington --

Deaths from liver-destroying hepatitis C are on the rise, and new data show Baby Boomers especially should take heed - they are most at risk.

Federal health officials are considering whether anyone born between 1945 and 1965 should get a one-time blood test to check if their livers harbor this ticking time bomb. The reason: Two-thirds of people with hepatitis C are in this age group, most unaware that a virus that takes a few decades to do its damage has festered since their younger days.

The issue has taken new urgency since two drugs hit the market last summer that promise to cure many more people than ever was possible. Research published Monday says testing millions of the middle-aged to find those who need the pricey treatment would be worth the cost, saving thousands of lives.

"One of every 33 Baby Boomers are living with hepatitis C infection," says Dr. John Ward, hepatitis chief at the Centers for Disease Control and Prevention. "Most people will be surprised, because it's a silent epidemic."

Don't think you need to worry? Yes, sharing a needle while injecting illegal drugs is the biggest risk factor for becoming infected with this blood-borne virus. But before 1992, when widespread testing of the blood supply began, hepatitis C commonly was spread through blood transfusions. Plus, a one-time experiment with drugs way back in high school or college could have been enough.

About 3.2 million Americans are estimated to have chronic hepatitis C, but at least half of them may not know it. The virus, which affects 170 million people worldwide, can gradually scar the liver and lead to cirrhosis or liver cancer. It is a leading cause of liver transplants.

A CDC study published Monday analyzed a decade of death records and found an increase in death rates from hepatitis C. In fact, in 2007 there were 15,000 deaths related to hepatitis C, higher than previous estimates - and surpassing the nearly 13,000 deaths caused by the better-known AIDS virus.

Perhaps more surprising, three-fourths of the hepatitis deaths occurred in the middle-aged, people 45 to 64, researchers reported in Annals of Internal Medicine.

"Mortality will continue to grow for the next 10 to 15 years at least unless we do something different" to find and treat the silent sufferers, Ward says.