The natural histories of hepatitis B virus (HBV) and hepatitis C virus (HCV) are very different in children, compared with their progress in adults, and depends on age at time of infection, mode of acquisition, ethnicity, and genotype, according to a review in a special pediatric issue of Clinics in Liver Disease.

An enlargement of a hepatitis C vaccine is shown, Courtesy NIH

Most children infected perinatally or vertically continue to be asymptomatic but are at uniquely higher risk of developing chronic viral hepatitis and progressing to liver cirrhosis and hepatocellular carcinoma (HCC), according to Krupa R. Mysore, MD, and Daniel H. Leung, MD, both of the Baylor College of Medicine, Houston. In addition, because the risk of progression to cancer along with such other liver damage is high in children, the reviewers stated that HCV and HBV can be classified as oncoviruses.

Their article assessed overall epidemiology, viral characteristics, and immune responses, as well as prevention, clinical manifestations, and current advances in the treatment of hepatitis B and C in children.

Because of the introduction of universal infant vaccination for HBV in the United States in 1991, the incidence of acute hepatitis B in U.S. children (those aged less than 19 years) has decreased from approximately 13.80/100,000 population (in children aged 10-19 years) in the 1980s to 0.34/100,000 population in 2002, Dr. Mysore and Dr. Leung wrote.

However, they added that those children who have chronic HBV remain at high risk for HCC, with a 100-fold greater incidence, compared with the HBV-negative population.

Similarly, HCV is a significant problem in children, with an estimated prevalence in the United States of 0.2% and 0.4% for children aged 6-11 years and 12-19 years, respectively. Vertical transmission from the mother is responsible for more than 60% of pediatric HCV infection and adds approximately 7,200 new cases in the United States yearly. Older children can acquire the virus through intravenous and intranasal drug use and high-risk sexual activity, they stated.

“Our understanding of the pathobiology and immunology of hepatitis B and C is unprecedented. As new antiviral therapies are being developed for the pediatric population, the differences in management and monitoring between children and adults with HBV and HCV are beginning to narrow but are still important,” the authors wrote.

They pointed out that soon-to-be-available treatments for HCV will be curative in children aged as young as 3 years. “[T]his will change the natural history of HCV and the prevalence of hepatocellular carcinoma over the next several decades for the better,” Dr. Mysore and Dr. Leung concluded.

They reported that they had no conflicts of interest to disclose.

SOURCE: Mysore KR et al. Clin Liver Dis. 2018; 22:703-22.