Natural History of Hepatitis C Virus Infection in Children

Abstract

Hepatitis C was first cloned and discovered to be a major cause of non-A, non-B hepatitis in 1989. Hepatitis C virus (HCV) is a RNA virus within the Flaviviridae family and comprises the genus Hepacivirus, of which there are six known genotypes. HCV is now known to be a leading cause of chronic liver disease in both industrialized and developing countries. Recent estimates suggest that over 200 million people worldwide have been infected with hepatitis C virus with an additional 3–4 million newly infected annually (El-Shabrawi MH, Kamal NM. World J Gastroenterol 19:7880, 2013). Eleven million of those globally infected with HCV are thought to be under 15 years of age (Gower E, Estes C, Blach S et al. J Hepatol 61:S45, 2014). Infection with HCV most commonly leads to persistent infection and can progress to chronic liver disease, cirrhosis, or hepatocellular carcinoma. While children account for a small proportion of the infected population, many of these children develop chronic hepatitis C and thus are at risk for its complications. The worldwide prevalence of HCV infection in children varies geographically, ranging from 0.05% to 0.36% in the USA (1.3% of children over the age of 6 (Mack CL, Gonzalez-Peralta RP, Gupta N et al. J Pediatr Gastroenterol Nutr 54:838, 2012)) and Europe to 1.8–5.8% in certain developing countries. The highest prevalence reported is in Egypt, sub-Saharan Africa, Amazon basin, and Mongolia (El-Shabrawi MH, Kamal NM. World J Gastroenterol 19:7880, 2013). Including individuals who were previously exposed but cleared the infection with those infected, the prevalence of HCV antibody positivity in North America is thought to approximate 0.2% of 6–11-year-olds and 0.4% of 12–19-year-olds (Mack CL, Gonzalez-Peralta RP, Gupta N et al. J Pediatr Gastroenterol Nutr 54:838, 2012). While a lot of what is known about hepatitis C comes from studying adults with the disease, children and adults demonstrate differences in modes of acquisition and transmission, rates of clearance and progression, and perhaps in response to treatment.