Perinatal Transmission of the Hepatitis B Virus

Clinical Scenario

A 20-year-old woman in the first trimester of pregnancy is found to be positive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg). Subsequent testing indicates that she has high serum levels of hepatitis B virus (HBV) DNA, with normal serum alanine aminotransferase (ALT) levels and no clinical evidence of hepatosplenomegaly.

The patient has questions about how to prevent perinatal transmission of HBV to her infant. Specifically, she requests information about the success of immunoprophylaxis with HBV vaccine and high- titer anti-HBs immunoglobulin (HBIg). She also requests information about the potential use of antiviral therapy. Will this reduce the risk to the infant? What is the effect on her disease?

Perpetuation of the Cycle

Chronic HBV infection, estimated to affect > 350 million people worldwide, is a substantial source of morbidity and mortality from cirrhosis and hepatocellular carcinoma.^[1] The ongoing cycle of transmission of HBV from an infected mother to her newborn during the perinatal period is an important source of infection.^[2,3,4,5]

The risk for chronic HBV infection is inversely proportional to age at the time of exposure; thus, exposure to HBV at birth imparts > 90% risk of developing chronic hepatitis B. This rate of chronicity is much higher than the rate after acquisition at any other time of life: For example, 25%-30% of children infected later in childhood and approximately 5% of adults will develop chronic HBV infection.^[2,3,4,5]

Worldwide adoption of universal hepatitis B vaccination for all newborns regardless of maternal HBsAg status has been successful, with markedly reduced rates of overt HBV infection in children and adolescents.^{[1,2,3,4,5,6]} However, the infant born to an HBV-infected mother requires additional immunoprophylaxis with HBIg. In the absence of immunoprophylaxis, infants born to chronically infected HBeAg-positive mothers are approximately 10 times more likely to develop persistent HBV infection than those born to mothers who are HBeAg- and anti-HBe–negative.^[7,8]

Immunoprophylaxis reduces the risk substantially. Therefore, the most common reasons for perpetuation of this cycle are failure of immunoprophylaxis, which occurs in 5%-10% of cases, and underutilization of the recommended intervention in regions that are endemic for HBV infection.

However, encouraging data suggest that aggressive screening and intervention can break this mother-to-infant cycle; highly effective screening, prophylactic, and treatment strategies hold the promise of significantly reducing the burden of HBV infection. We will review the rationale for and issues related to the efforts to prevent transmission of HBV infection in the perinatal period.

Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.

Cite this: William F. Balistreri. Perinatal Transmission of the Hepatitis B Virus - Medscape - Jun 04, 2015.

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