Neonatal Hepatitis B Virus (HBV) Infection

HBV infection occurs during delivery from an infected mother. The risk of transmission is 70 to 90% from women seropositive for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg—see Serology) at the time of delivery. Women without the e antigen transmit the infection only 5 to 20% of the time (1).

Mother–infant HBV transmission results primarily from maternofetal microtransfusions during labor or from contact with infectious vaginal fluid. Transplacental transmission is identified in < 2% of infections. Postpartum transmission occurs rarely through exposure to infectious maternal blood, saliva, stool, urine, or human milk. Up to 90% of infants infected perinatally will develop chronic infection, and perinatally acquired HBV infection may be an important viral reservoir in certain communities (1).

Most neonates with HBV infection are asymptomatic but develop chronic, subclinical infection characterized by persistent HBsAg antigenemia and variably elevated transaminase activity. Many neonates born to women with acute hepatitis B during pregnancy are of low birth weight, regardless of whether they are infected.

Infrequently, infected neonates develop acute, symptomatic hepatitis B, which is usually mild and self-limited. They develop jaundice, lethargy, growth and weight faltering, abdominal distention, and clay-colored stools.

Occasionally, infection is severe, with hepatomegaly, ascites, and conjugated hyperbilirubinemia.

Rarely, the disease is fulminant and even fatal. Fulminant disease occurs more often in neonates whose mothers are chronic carriers of hepatitis B.

• Serologic testing

• Laboratory testing (HBsAg, HBeAg, e antibody, HBV DNA quantification, blood count including platelets, liver function testing)

• Liver ultrasound

Diagnosis of neonatal HBV infection is by serologic testing, including measurement of HBsAg, HBeAg, antibody to hepatitis B e antigen (anti-HBe), and quantitation of HBV DNA in blood. Other initial tests include complete blood count (CBC) with platelets, alanine aminotransferase (ALT) and alpha-fetoprotein levels, and liver ultrasound.

Family history of liver cancer or liver disease is noted because of the long-term risk of hepatocellular carcinoma. If testing suggests HBV infection, consultation with a pediatric hepatologist is recommended.

• Supportive care

• Sometimes nucleosides (in consultation with a pediatric hepatologist)

Symptomatic care and adequate nutrition are needed. Neither corticosteroids nor hepatitis B immune globulin (HBIG) is helpful for acute infection. No therapy decreases the likelihood of developing chronic, subclinical hepatitis once infection is acquired. Symptomatic care and adequate nutrition are needed. Neither corticosteroids nor hepatitis B immune globulin (HBIG) is helpful for acute infection. No therapy decreases the likelihood of developing chronic, subclinical hepatitis once infection is acquired.

All children with chronic HBV infection should be immunized with hepatitis A vaccinehepatitis A vaccine.

Children with chronic HBV infection may benefit from nucleosides or nucleotide analogues, but these should be used only in consultation with a pediatric hepatologist.

Rarely, severe illness may require liver transplantation.

Long-term prognosis is not predictable. However, chronic HBV infection early in life does increase the risk of subsequent liver disease including chronic hepatitis, cirrhosis, end-stage liver disease, and hepatocellular carcinoma.

Pregnant patients should be tested for HBsAg during an early prenatal visit. If testing does not occur at that time, they should be tested when admitted to the hospital for delivery. Some women who are HBsAg-positive are treated with antiviral therapy (tenofovir disoproxil fumarate or tenofovir alafenamide) during the third trimester, which may prevent perinatal transmission of HBV (Pregnant patients should be tested for HBsAg during an early prenatal visit. If testing does not occur at that time, they should be tested when admitted to the hospital for delivery. Some women who are HBsAg-positive are treated with antiviral therapy (tenofovir disoproxil fumarate or tenofovir alafenamide) during the third trimester, which may prevent perinatal transmission of HBV (1).

Neonates whose mother is known HBsAg-positive or mother has other evidence of HBV infection (eg, presence of HBV DNA, HBeAg-positive, or known to be chronically infected with HBV) should receive within 12 hours of birth: 1 dose of IM hepatitis B immune globulin (HBIG) and the first dose in the series of IM should receive within 12 hours of birth: 1 dose of IM hepatitis B immune globulin (HBIG) and the first dose in the series of IMrecombinant HBV vaccine (HBIG and the first HBV vaccine dose are given concurrently but at a different injection sites) (2). The HBV vaccine series is then completed, the second dose is given at 1 to 2 months, and the third dose is given 6 to 18 months after the first. If the infant weighs < 2 kg, the first dose of vaccine may be less effective, so the infant should receive 3 additional doses of vaccine starting 1 to 2 months after birth per manufacturer's guidance.

Testing for HBsAg and anti-HBs at 9 to 12 months (or 1 to 2 months after completion of vaccination) is recommended for all infants born to HBsAg-positive mothers (3).

Neonates whose mother has unknown HBsAg status at the time of delivery should also receive their first dose of vaccine within 12 hours of birth. For infants < 2 kg, the first dose is given concurrently with HBIG at a different site. For infants ≥ 2 kg and whose mothers can be tested for HBsAg and in whom follow-up is ensured, HBIG can be delayed up to 7 days and is given if the mother tests positive for HBsAg.

Neonates whose mother is known HBsAg-negative should receive their first dose of HBV vaccine within 24 hours of birth if they are medically stable and weigh ≥ 2 kg. For infants < 2 kg, 1 dose of vaccine should be given at age 1 month or before hospital discharge (4).

(See also the Center for Disease Control and Prevention's hepatitis B vaccination notes.)

Separating a neonate from an HBsAg-positive mother is not recommended, and breastfeeding does not seem to increase the risk of postpartum HBV transmission, particularly if HBIG and HBV vaccine have been given (1). If a breastfeeding patient has bleeding nipples, milk should be discarded from the affected breast while continuing to feed or pump from the unaffected breast until the bleeding nipple is healed to prevent direct exposure of the neonate to blood (5).