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Perinatal Hepatitis B

December 5, 2025: Public Health Reaffirms Continued Adherence to the California Department of Public Health’s Hepatitis B Vaccination Guidance for Children. Click here to read the press release.

Introduction - Perinatal Hepatitis BUpdated 12-23-25
  • Hepatitis B virus (HBV) infection in a pregnant person can be passed to their child during pregnancy or childbirth. This is called perinatal transmission.
  • All pregnant people who are at risk for HBV infection and have not been vaccinated previously should get vaccinated.
  • HBV infection in infants can lead to long-term serious health effects if left untreated. Infants with HBV infection have a 90% chance of developing a chronic HBV infection, and 25% of those may develop cirrhosis of the liver or liver cancer.
  • HBV vaccination among newborns is safe and the best way to protect infants against HBV infection.
Information for the Public
Perinatal Hepatitis B Overview

Hepatitis B is a serious infection that can be transferred from a pregnant person to their infant during pregnancy or childbirth. Babies who are infected can often have severe disease affecting their liver when they are older.

Key Strategies to Prevent Perinatal Transmission:
Screening and Treatment for Pregnant Persons:

  • Early detection: Get tested for hepatitis B virus early in pregnancy, preferably the first trimester. This will help identify if you are infected and allow for timely intervention to protect your baby.
  • In some cases, pregnant persons with high levels of hepatitis B virus may be treated with medication to reduce the risk of perinatal transmission.

Vaccination:

  • Infant vaccination:
    • Los Angeles County Department of Public Health, along with the American Academy of Pediatrics, the American College of Obstetrics/Gynecology, and California Department of Public Health, recommend all infants receive hepatitis B vaccine (Engerix-B or Recombivax HB) within the first day of life.
    • The hepatitis B vaccine birth dose is safe and protects all newborns, even if their birth mom did not get appropriate hepatitis b virus testing or there were delays in getting the lab result. Also, it protects infants from getting infected from household contacts who may not know they are infected with hepatitis b virus because they don’t have symptoms.
    • Infants born to pregnant persons known to have a diagnosis of hepatitis B will need to receive hepatitis B vaccine and immune globulin (HBIG) within 12 hours of birth.
    • Completion of the 3-dose infant hepatitis B vaccine series is critical to ensure lifelong protection against hepatitis B.
  • Partner vaccination: Hepatitis B virus can also be transmitted through bodily fluids or from sharing common household items like nail clippers. For this reason, household and sexual contacts should be vaccinated against hepatitis B to reduce the risk of transmission to the infant.

After baby leaves hospital:

  • If an infant is born to a person who is known to be infected with hepatitis B, their pediatrician will do a blood test on the baby after the baby has received all 3 doses of the infant hepatitis B vaccine series to make sure the infant is protected from hepatitis B virus. Blood tests are not necessary for infants who are born to persons not infected with hepatitis B.
  • Breastfeeding is still encouraged. Hepatitis B virus is not commonly transmitted from mother to infant through breastmilk, especially if the infant receives vaccine and HBIG. Also, breastmilk has multiple benefits to the newborn’s health.
  • For more information about the hepatitis B vaccine schedule, please see LAC DPH website on hepatitis B vaccine.
Information for Providers
Overview

Hepatitis B virus infection in a pregnant person poses a serious risk to an infant at birth. Without timely post-exposure immunoprophylaxis, approximately 90% of infants born to HBsAg-positive people will acquire chronic HBV infection, and approximately one-fourth of those will prematurely die from chronic liver disease or liver cancer.

Guidelines for Prenatal Providers

Prenatal care providers play an essential role in the prevention of perinatal transmission of hepatitis B. Providers should:

  • Test all pregnant persons for hepatitis B surface antigen (HBsAg) during each pregnancy, preferably in the first trimester.
    • Test all pregnant people who are HBsAg-positive for HBV DNA. This information will help the clinician decide whether to prescribe maternal antiviral therapy to reduce the risk of perinatal hepatitis B virus transmission.
    • Re-test HBsAg-negative pregnant people before delivery if they have clinical hepatitis or if they were at high risk for hepatitis B exposure during pregnancy. People at high risk for hepatitis B virus infection include:
      • Household or sexual contacts of HBsAg-positive persons
      • People who use or have used injection drugs
      • People who have had more than one sex partner in the past six months
      • People who have been evaluated or treated for a sexually transmitted infection
      • People with HIV, chronic liver disease, or end-stage renal disease
      • People who have traveled to countries with a hepatitis B prevalence of ≥2%. You can check prevalence rates at the World Health Organization’s Viral Hepatitis Country Profile dashboard.
  • Provide a copy of the original laboratory report indicating the pregnant person's HBsAg-positive status to the hospital or birthing facility where the delivery is planned and to the health care provider who will care for the infant.
  • Refer all HBsAg-positive pregnant people to a liver specialist for evaluation and possible antiviral treatment.
  • The American Association for the Study of Liver Diseases (AASLD) recommends maternal antiviral therapy in the third trimester for pregnant people with HBV DNA >106 copies/mL (>200,000 IU/mL) to reduce the risk of perinatal hepatitis B transmission.
  • If a pregnant person has a confirmed positive test result for HBsAg and then tests negative for HBsAg during the same pregnancy (i.e., has discrepant results), this alone does not rule out hepatitis B infection. Retest pregnant persons with discrepant hepatitis B surface antigen (HBsAg) lab results for the following (see table below for interpretation):
    • HBV DNA
    • Total anti-HBc (aka HBcAb, Hepatitis B Core Antibody)
    • IgM anti-HBc (aka Hepatitis B IgM Core Antibody)
    • Anti-HBs (aka HBsAb, Hepatitis B Surface Antibody)
  • Recommend HBsAg testing and/or vaccination for family members and sexual partners.
  • Educate patients on perinatal hepatitis B transmission and encourage patients to breastfeed their infant, as the benefits of breastfeeding largely outweigh the risk of transmission. The risk of perinatal hepatitis B transmission through breastfeeding is negligible if infants born to HBV-positive mothers receive HBIG and the hepatitis B vaccine birth dose.
HBV markers table

Table: Interpretation of HBV Markers of Infection Following Discrepant HBsAg Lab Results During Pregnancy
Guidelines for Birthing Hospitals

The American Academy of Pediatrics (AAP) and the Immunization Action Coalition (IAC) recommend birthing hospitals implement protocols and procedures to prevent perinatal transmission. Failure to vaccinate and provide HBIG to infants born to HBsAg-positive persons can result in perinatal HBV transmission. Here are three steps to prevent perinatal transmission:

1. Review HBsAg laboratory report upon admission

  • Review patient’s HBsAg lab at admission to confirm the lab is from the current pregnancy and the interpretation of test results is correct.
  • Document maternal HBsAg status in maternal and infant medical records.

2. Test pregnant persons with unknown HBsAg status

  • If the patient does not have a HBsAg lab report with a specimen collection date during this pregnancy, perform HBsAg testing immediately.

3. Administer hepatitis B vaccine to all infants & HBIG if necessary (see figure for timing based on birthweight and birthing parent’s HBsAg status)

Figure

NOTE: Only single-antigen hepatitis B vaccine should be given at birth (Recombivax HB or Engerix-B). Pediarix or Vaxelis should not be administered before six weeks of age.

Report all infants born to HBsAg-positive persons to the Perinatal Hepatitis B Prevention Unit via fax at (213) 351-2781, or email at vpdc-phb@ph.lacounty.gov.

Guidelines for Pediatric Providers
  • AAP recommends infants born to HBsAg-positive persons receive single antigen dose of hepatitis B vaccine (Engerix-B or Recombivax HB) and hepatitis B immune globulin (HBIG) within 12 hours of birth, regardless of birthweight or any maternal antenatal treatment with antiviral medications.
  • Infants born to HBsAg-positive persons should complete the hepatitis B vaccination series to ensure protection against hepatitis B. For infants with birthweight < 2000 gm, a 4-dose series is needed; for infants with birthweight ≥ 2000 gm, a 3-dose series is needed.
  • Administer the final dose no earlier than 6 months of age (minimum age of 164 days includes 4-day grace period).

Post-Vaccination Serologic Testing

  • Post-vaccination serologic testing (PVST) helps identify if an infant born to an HBsAg-positive person has an adequate immune response to an initial hepatitis B vaccine series. If they do not, the infant may require additional vaccination. PVST can also identify infants with HBV infection.
  • After completion of the hepatitis B infant vaccine series, perform PVST on infants 9-12 months of age or 1-2 months after completion of at least 3 doses of a hepatitis B vaccination series, whichever occurs latest.
  • PVST is only recommended for infants who were exposed to hepatitis B during birth and have completed their full 3- or 4-dose infant vaccine series. It should not be performed on infants who are not exposed or before the completion of the full series of vaccine. A positive or a negative antibody test after 1 or 2 doses of vaccine is of unknown clinical significance and should not inform whether a child needs additional doses without peer-reviewed published studies evaluating the long-term efficacy of an alternative dosing schedule in infants.
    Request the following labs:
    • HBsAg (Hepatitis B Surface Antigen)
    • Anti-HBs, quantitative (Hepatitis B Surface Antibody)
  • NOTE: Antibody to hepatitis B core antigen (anti-HBc) testing of infants is not recommended because passively acquired maternal anti-HBc might be detected in infants born to a person who is HBsAg-positive up to age 24 months.
  • HBsAg-negative infants with anti-HBs levels ≥10 mIU/mL after their full 3- or 4-dose series are protected and need no further medical management.
  • HBsAg-negative infants with anti-HBs <10 mIU/mL should be revaccinated with a single dose of hepatitis B vaccine and receive a second round of PVST 1–2 months later. Infants whose anti-HBs remains <10 mIU/mL following the single dose revaccination should then receive two more doses of hepatitis B vaccine to complete the second series, followed by a third round of PVST 1–2 months after the final dose.
  • For more information, see California Department of Public Health guidelines for pediatric providers to prevent chronic hepatitis B in children.
  • Infants born to persons with HBAg unknown status are recommended to receive single antigen dose of hepatitis B vaccine (Engerix-B or Recombivax HB) within 12 hours of birth.
  • If infant birthweight is ≥ 2000 gm, HBIG should be administered
    • Within 7 days of birth if maternal HBsAg status is confirmed positive
    • By 7th day of life or at hospital discharge (whichever is first) if maternal HBsAg status remains unknown.
  • If infant birthweight is < 2000 gm, HBIG should be administered within 12 hours of birth unless maternal HBsAg status is confirmed negative by that time.
  • The Los Angeles Department of Public Health, along with the West Coast Health Alliance, the American Academy of Pediatrics (AAP), the American College of Obstetricians and Gynecologists (ACOG), and the American Nurses Association continue to strongly recommend that providers routinely offer and administer the first dose of the hepatitis B vaccine to all eligible newborns.
  • This recommendation remains in place despite a recent vote by CDC’s Advisory Committee on Immunization Practices (ACIP) to change a decades-long recommendation for the hepatitis B birth dose from a universal approach to “individual-based decision-making” for infants born to mothers who test hepatitis B-negative.
  • Hepatitis B virus is highly infectious. Children may be infected by unknown sources in their everyday lives. For more information on the hepatitis B birth dose, please see our FAQs for providers.
  • If infant birthweight is ≥ 2000 gm, the hepatitis B vaccine should be administered within 24 hours of birth.
  • If infant birthweight is < 2000 gm, the hepatitis B vaccine should be administered at 1 month of age or at hospital discharge (whichever is first).
Reporting

Hospitals

Report all births of HBsAg-positive pregnant persons or unknown HBsAg status to the Perinatal Hepatitis B Prevention Unit (PHBPU) at Los Angeles County Department of Public Health's Vaccine Preventable Disease Control Program within 24 hours of birth. Fax the Delivery Report to (213) 351-2781 or send via secure email to vpdc-phb@ph.lacounty.gov.

Laboratories can also contact the Perinatal Hepatitis B Prevention Unit at 213-351-7800 or vpdc-phb@ph.lacounty.gov.



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    • Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

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