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Mother-to-child Transmission of Hepatitis B

  • In Hong Kong, mother-to-child transmission (MTCT) is the major route of transmission of hepatitis B.
  • Hepatitis B virus (HBV) can be transmitted from mothers with chronic hepatitis B (CHB) to their babies during normal spontaneous delivery or Caesarean section.
  • Up to 90% of newborn babies infected with HBV would develop CHB.
  • In 2020, about 3.4% of pregnant women had been infected with HBV in Hong Kong. All pregnant women have to receive blood testing for hepatitis B during antenatal check-ups, in order to know their own infection status of hepatitis B.
  • If appropriate measures are taken, MTCT of hepatitis B could be prevented.

Hepatitis B vaccine

  • Hepatitis B vaccine
  • Regardless of the hepatitis B status of mothers, all newborn babies should receive the birth dose of hepatitis B vaccination in hospital. Afterwards, they should receive the second and third dose of the vaccination at the age of one month and six months respectively.
  • Hepatitis B vaccine
  • After completing the three-dose course of vaccination, 90 - 95% of babies can produce adequate protective antibody to protect them from HBV infection.

Hepatitis B immunoglobulin

  • Babies born to HBV-infected mothers must be given hepatitis B immunoglobulin within 24 hours after birth for immediate extra protection.

Post-vaccination serologic testing

  • Babies born to mother infected with HBV should receive post-vaccination serologic testing (PVST), which can determine whether the babies are protected from HBV infection.
  • PVST consists of blood tests on hepatitis B surface antibody (anti-HBs) and hepatitis B surface antigen (HBsAg). It assesses a baby's immune response to hepatitis B vaccination and hepatitis B infection status.
  • PVST is conducted at the age of 9-12 months after the 3-dose course of hepatitis B vaccination (or 1 - 2 months after completion of the final dose of the primary vaccination series if the hepatitis B vaccination is delayed).
  • With effect from January 2022, Maternal and Child Health Centres arrange serologic testing after hepatitis B vaccination for babies born to mothers infected with HBV in or after April 2021. For details of this initiative, please view the fact sheet and press release.
  • With effect from June 2022, PVST will also be arranged for babies born to mothers infected with HBV in or after October 2020 before the age of 24 months.
    'Post-vaccination serologic testing for babies born to mothers infected with hepatitis B virus' fact sheet

Antiviral medication

  • Pregnant women with high HBV viral load may use antivirals in last trimester to reduce the viral load and the risk of MTCT of HBV.
  • All public hospitals with obstetric services under the Hospital Authority provide antiviral treatment option for pregnant women with high HBV viral load.
  • Postnatal women have to continue medical assessment and management of hepatitis, to determine the need for continuing antiviral medication.
  • Please consult doctor for details on antiviral treatment.

Health educational materials

Useful link

Family Health Service of Department of Health – Hepatitis B Vaccine