Neonatal HBV

Background

Epidemiology

• Transmitted perinatally during delivery (rarely transmitted in utero)
• Transmission from HBaAg-positive mothers is 30% if HBeAg-negative and 85% if HBeAg-positive

Clinical Manifestations

• 80-90% of infected infants will develop chronic infection
• Mostly asymptomatic

Prevention

• Mother should take tenofovir starting at 28-32 weeks gestation if viral load is greater than 200,000 IU/mL, until 3 months postpartum
  • See also hepatitis B in pregnancy
• If mother has active hepatitis B (that is, HBsAg is positive) or if her status is unknown, then consider post-exposure prophylaxis with hepatitis B immune globulin and hepatitis B vaccine given within 12 hours of life
  • Vaccine prevents about 90% of infections, with HBIG adding a bit more
  • HBIG can be given up to 7 days of life but is most effective when given earlier
  • Vaccine and HBIG should be given in separate limbs
  • Overall, decreases transmission from 30-85% down to 1%
• No need for Cesarean section to prevent transmission
• Monitoring
  • Completion of routine vaccination schedule
    • The initial vaccine for infants with birth weight <2 kg does not count towards their schedule
  • Postvaccination HBsAg serology is recommended for children born to HBsAg-positive mothers
    • Usually at age 9 to 12 months
    • HBsAg negative with HBsAb ≥10 mIU/mL: no further management
    • HBsAg negative with HBsAb <10 mIU/mL: give another dose of vaccine and repeat testing in 1 to 2 months
      • If still <10 mIU/mL, then give two additional doses to complete a full second series and repeat testing in 1 to 2 months
    • HBsAg positive: refer for management
  • Even if not infected, maternal HBcAb may persist in the baby up to 24 months of age
• Also see article on neonatal HIV

Further Reading

• Prevention of Hepatitis B Virus Infection in the United States: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep. 2018;67(RR-1):1-31. doi: 10.15585/mmwr.rr6701a1