NEW YORK, Sep 15 (Reuters Health) -- German children who had heart surgery before 1991, when routine screening for hepatitis C in donated blood began in Germany, had a high risk of becoming infected with the virus, researchers report. An average of 20 years after surgery, however, the infection cleared up on its own in many of these children and it had caused few serious health problems in others, leading researchers to suspect that the virus may be less harmful in children than in adults.
Infection with the hepatitis C virus, which is usually transmitted through blood transfusions or sharing needles to inject drugs, can lead to liver damage, including liver cancer and a condition called cirrhosis that causes scarring of the liver. Although screening of the US blood supply has reduced the odds of catching the virus by a blood transfusion from 1 in 5,000 to 1 in 103,000, an estimated 2.7 million Americans are chronically infected with hepatitis C.
Dr. Manfred Vogt, of the Technical University of Munich, Germany, and colleagues studied 458 children who had undergone heart surgery before Germany began screening its blood supply for hepatitis C. On average, the children had surgery before they were 3 years old, the researchers report in the September 16th issue of The New England Journal of Medicine. The investigators tested blood samples taken from the patients in 1996 or 1997, nearly 20 years after their childhood heart surgery.
At that time, the researchers tested for antibodies to hepatitis C, which are present if a person has ever been exposed to hepatitis C, even if the virus is no longer present. In addition, they also looked for hepatitis C RNA, which indicates that a person is still infected.
Antibodies were present in 67 (14.6%) children who had undergone surgery, compared with 3 out of 458 children (0.7%) who had never had surgery, Vogt and his associates report. However, just 37 of the children who had undergone surgery tested positive for genetic material from the virus (HCV RNA), meaning that 30 children had once been infected but were now free of the virus. Additional laboratory tests confirmed that these 30 children no longer had the infection.
Even among the children who still were infected with hepatitis C, the virus did not appear to be taking a heavy toll on the liver. Out of 17 children who underwent a liver biopsy, just three showed signs of progressive liver disease, according to Vogt's team. In contrast, cirrhosis tends to appear within 20 years of infection in about 20% of adults with hepatitis C.
"We found that children who had undergone cardiac surgery in Germany before the implementation of blood-donor screening for hepatitis C were at substantial risk for HCV infection," Vogt and colleagues write.
However, despite the fact that all patients who had a liver biopsy were infected with what is thought to be the most virulent form of HCV, "past or persistent hepatitis C virus infection was not associated with clinical or biochemical signs of liver disease," the researchers note.
"These findings suggest that in our study group, chronic hepatitis C was mild and had a low rate of progression even after two decades," they conclude.
However, in an editorial that accompanies the study, Dr. Maureen M. Jonas, of Children's Hospital in Boston, points out "(we) do not know whether more serious manifestations of liver disease will appear 30 or 40 years after infection."
"Thus, it is important to screen and follow patients who are at risk for hepatitis C and to do more than simply reassure infected children and their families," she concludes.
