16 This accounts for the wide range in rates of VT (1–28%) 7 – 17 seen among HBV studies. There is no universally accepted standard for the diagnosis of HBV infection in infants. One primary difference between these studies is the method used to diagnose HBV infection in neonates. There are a number of factors that impact the rate of VT, which will be discussed in greater detail below. The reported rates of VT range between 1% and 28% 7 – 17 ( Table 1). 1, 3, 6 This vast contrast speaks to the differences in immune response observed in children versus adults. If exposed to HBV, neonates have a 90% risk of acquiring chronic HBV infection, whereas adults have a 5–10% chance of developing chronic infection. 5 In infants and children, HBV is largely acquired by VT. 4 The prevalence of chronic HBV infection varies by geographical region, affecting less than 2% in the United States and Western Europe, 2–8% in the Mediterranean and South America and up to 20% in Asia and Africa. HBV EpidemiologyĪpproximately 370 million people are infected with chronic HBV worldwide. The purpose of this review is to clarify what is currently known about the mechanisms of VT of both hepatitis B virus (HBV) and hepatitis C virus (HCV). Overall, our understanding of the mechanisms of VT of chronic viral hepatitis is poor. While many risk factors for VT have been identified, the underlying pathophysiology of each are not well known. Often, studies are limited by ethical concerns surrounding pregnancy and fetal well-being. 1 – 3 Currently, there are limited data available on viral hepatitis in pregnancy and VT. In children, vertical transmission (VT) is the primary route of transmission of viral hepatitis. Despite these differences, the key to prevention with both viruses is screening women prior to and during pregnancy.Ĭhronic viral hepatitis remains a significant global health concern. In contrast, there are no preventative interventions available for HCV. There are several alternatives for prevention of HBV VT, including antiviral medications during the third trimester of pregnancy and HBV vaccine, as well as hepatitis B immunoglobulin administration to infants post-partum. Prevention of VT differs greatly between HBV and HCV. HBV and HCV share some common risk factors for VT, including maternal viral load, human immunodeficiency virus co-infection and neonatal sex. Both viruses also have the potential for transmission during delivery, when there is increase chance of maternal–fetal blood exposure. Hepatitis B surface antigen is unable to cross the placenta and, therefore, relies on processes like transplacental leakage, placental infection, cellular transmission by peripheral blood mononuclear cells, and germline transmission. VT of HBV primarily occurs by intrauterine transmission (IUT). VT for both viruses can occur during the intrauterine or peripartum period. The rate of VT ranges from 1–28% with hepatitis B virus (HBV) and 3–15% with hepatitis C virus (HCV). Vertical transmission (VT) is the primary route of transmission of viral hepatitis in children.
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