Type of Hepatitis That Endangers Adults Rarely Harms Children
Sept. 16, 1999 (Seattle) -- A form of hepatitis that often damages the livers of adults almost never causes problems among children who are infected, according to study in the New England Journal of Medicine. Scientists say the finding eventually could lead to new treatments for the 2.7 million Americans who carry the virus known as hepatitis C.
Researchers from the Technical University of Munich in Germany looked at 458 people who had received blood transfusions as infants during the 1970s and 1980s, usually before age 3. Transfusions often transmitted hepatitis C before blood banks were able to screen donated blood for the virus. Germany began screening in 1991, the U.S. in 1992.
Blood tests done 20 years after the patients received their transfusions showed that about 15% had developed immunity to the hepatitis C virus, indicating they had been exposed to it. However, genetic tests found that about half of the people with the immunity were no longer infected with the virus. Even more surprising, just three people with active infection had any sign of liver damage and they all had other diseases that also could have caused the damage.
The scientists say the results are startling because when adults are infected with hepatitis C, about one in five develops cirrhosis of the liver, a type of scarring that can cause liver failure, within 20 years. Also, about one in 10 adults with cirrhosis caused by hepatitis C develops liver cancer.
Hepatitis C is one of several forms of hepatitis that can cause liver damage. It can be transmitted through sexual contact or blood transfusions. Since the 1960's, the virus has become increasingly common in the U.S. and is one of the leading reasons for liver transplants. Most people with hepatitis C do not respond to drug treatment.
Maureen Jonas, MD, an associate professor of pediatrics at Harvard Medical School, tells - WebMD the study is "very reassuring" for people who were infected with hepatitis C as children. But Jonas, who wrote an editorial that accompanied the study, says such people still need to be monitored by their physicians in case liver problems occur. Also, she says, anyone who underwent a transfusion in the U.S. before 1992 should be tested for exposure to the virus.
But Jonas says the study is intriguing primarily because it shows that youth appears to protect people from the harmful effects of hepatitis C. One explanation may be that the immune systems of young children are better able to eliminate the virus from the body, she says. Another possibility is that adults who get hepatitis C are more likely to be infected with other viruses, and it is the combination of viruses that causes damage to the liver.
Jonas says scientists need to begin experiments to find out precisely why children with the virus don't get sick. "That's the key question," she says. "If we know that we may be able to find ways to protect adults who are infected."
The study was supported by the German Heart Center and the Children's University Hospital in Munich, Germany.