The following is a case study of an infant who failed to receive appropriate treatment at birth, and was infected with hepatitis B virus (HBV). This case illustrates the importance of establishing polices and procedures for the prevention of HBV infection among infants in King County.

Case study:

The infant’s mother was known to have a chronic hepatitis B infection (HBsAg positive, HBeAg status unknown) before delivery. She received little or no prenatal care, and delivered her infant 6 weeks prematurely at a King County hospital. The child was transferred to the NICU, and required immediate surgery. Public Health‘s Perinatal Hepatitis B Prevention Program (PHBPP) learned of the case approximately 6 weeks later during a routine call to the hospital around the time of the expected date of delivery to assure that PEP had been given (Hepatitis B surface antigen-positive pregnant women are reportable within 3 work days to Public Health, and we routinely follow-up on the infants of HBV-infected mothers).

During a chart review it was discovered that there were standing orders to administer PEP at birth for infants born to HBV-positive mothers, but for this patient the orders were not transferred to the NICU, and were not carried out. Upon realizing the error when the PHBPP program called, the infant was promptly given the first dose of hepatitis B vaccine. This was 6 weeks after birth.

Hepatitis B Immune Globulin (HBIG) administration is also recommended as soon as possible after birth to an infected mother, but has no benefit if not given within 7 days after birth. The infant received the second and third doses of the HBV vaccine series on time. However, post-vaccination testing at age 9 months showed that that the infant was HBsAg positive. The baby was referred to a pediatric gastroenterologist for evaluation of hepatitis B infection.

Further follow-up with the hospital revealed that the hospital had no policy or audit procedure to assure that the written and/or standing orders were carried out on infants who are admitted to the NICU directly after delivery. To address this gap, a hospital team was put in place to develop procedures to assure standing orders are followed in these instances.

For infants and children, the primary sources of HBV infection are perinatal transmission from infected mothers and horizontal transmission from infected household contacts. For a newborn infant whose mother is positive for both HBsAg and HBeAg, the risk for chronic HBV infection by age 6 months is 70% - 90% in the absence of PEP. For infants of women who are HBsAg positive but HBeAg negative, the risk for chronic infection is <10% in the absence of PEP. Hepatitis B vaccine and HBIG administered 12 - 24 hours after birth, followed by completion of a 3-dose vaccine series, has been demonstrated to be 85% - 95% effective in preventing acute and chronic HBV infection in infants born to women who are positive for both HBsAg and HBeAg.

Children who are not infected at birth remain at long-term risk for horizontal transmission from their infected mothers (and possibly other family members). In one study, 38% of infants who were born to HBsAg-positive mothers and who were not infected perinatally, became infected by age 4 years. In addition, children living with any chronically infected persons are at risk for becoming infected through percutaneous or mucosal exposures to blood or infectious body fluids (e.g., sharing a toothbrush, contact with exudates from dermatologic lesions, contact with HBsAg-contaminated surfaces). HBV transmission rates to susceptible household contacts of chronically infected persons have varied (range: 14% - 60%).

Take home messages:

Health care facilities with obstetrical and labor and delivery services should review their policies and procedures regarding the prevention of perinatal hepatitis B infection to ensure:

• Timely testing and reporting of HBsAg-positive mothers
  
• Standing orders for the administration of post-exposure prophylaxis to infants delivered to HBsAg-positive mothers
  
• Administration of the birth dose of hepatitis B vaccine to all newborns before discharge

Additional information on the prevention of perinatal hepatitis B infection and the management of pregnant women.