GP Connect Clinical feature by Adam Gregson, Nurse Practitioner, Hepatology, Royal Perth Hospital; Rachael Dunn, Clinical Nurse Specialist, Immunology, Perth Children’s Hospital; Dr Aleisha Anderson, Consultant Paediatrician, Infectious Diseases, Perth Children’s Hospital; Dr Marisa Gilles, Director Public Health Medicine, WA Country Health Service.
Chronic hepatitis B (CHB) is one of the biggest causes of liver cancer and, along with chronic hepatitis C, causes more than 70 per cent of liver cancers globally.
Hepatitis B is most commonly acquired early in life. More than 90 per cent of affected infants will develop lifelong chronic infection and inherit the liver cancer risk in addition to an increased risk for advanced fibrosis. Perinatal transmission therefore remains a significant concern in Western Australia (WA) and nationally.
If all appropriate preventative measures are taken, the risk of perinatal transmission can be reduced from up to 90 per cent to ≤1 per cent in most patients.¹
GPs are crucial in WA’s frontline response. You do not need to be a hepatitis B expert to make a difference in the outcomes for infants in WA.
These are the five things every GP should know
1. Screen with every pregnancy, not just the first
Irrespective of vaccination status, previous negative tests, country of birth or perceived risk, the only way to get the full picture on hepatitis B status is to do all three of these tests, every time:
- Hepatitis B surface antigen (HBsAg).
- Hepatitis B surface antibody (HBsAb).
- Hepatitis B core antibody (HBcAb).
2. A positive HBsAg is just the beginning
Pregnancy is not a reason to delay assessment or referral. If a positive HBsAg is returned, a DNA viral load and Hepatitis B e-antigen (HBeAg) should be requested promptly, as well as an overall assessment of liver function. If not done already, a coinfection screen should be completed including syphilis, human immunodeficiency virus (HIV), and hepatitis A, C and D.
3. Hepatitis B viral load is key
The normal treatment rules for CHB change in pregnancy, with antiviral treatment becoming antiviral prophylaxis. Those with a high viral load (>200,000 IU/ml) should receive tenofovir disoproxil in the third trimester, to substantially reduce the risk of perinatal transmission when combined with neonatal immunoprophylaxis.
4. The job doesn’t end at delivery
Regardless of whether the mother is taking antiviral treatment or has an undetectable viral load, all infants born to those with hepatitis B should:
- receive hepatitis B immunoglobulin (HBIG) as soon as possible (within 12 hours of birth).
- receive a full course of hepatitis B vaccination.
- have follow-up serology checked three months after the final vaccine dose (usually 9-12 months), both to exclude perinatal transmission and ensure immunity post-vaccination.
All infants, regardless of the mother’s status should receive a birth dose of hepatitis B vaccine (within 24 hours) and be vaccinated according to the WA immunisation schedule. The schedule includes three further doses of vaccine, with an additional dose for premature and low-birth-weight infants at 12 months. Vaccination also has an important role in preventing household or horizontal transmission in early childhood.
GPs have an important role in discussing the infant plan with the mother prior to delivery. If advice is needed regarding infant management, the Infectious Diseases team at Perth Children’s Hospital can be contacted for advice.
5. Think beyond the pregnancy
Each pregnancy provides an opportunity to diagnose unknown hepatitis B, test sexual/close/household contacts and vaccinate those who are susceptible. Everyone with CHB needs regular and lifelong monitoring, regardless of disease activity or phase of infection.
Avoid the pitfalls
- Myth: They were vaccinated for hepatitis B, so testing is not required.
- Fact: Normalising testing and avoiding assumptions about CHB risk/status is vital to avoid missed diagnoses. Screen with every pregnancy, completing all three tests – 1. HBsAg, 2. HBsAb, 3. HBcAb.
- Myth: Normal liver function tests (LFTs) mean no antivirals.
- Fact: In pregnancy, decisions to commence antiviral prophylaxis at the 3rd trimester are driven by viral load, rather than LFTs.
- Myth: Breastfeeding and vaginal delivery should be avoided.
- Fact: There is no evidence of hepatitis B transmission due to breastfeeding, provided infants receive HBIG/vaccinations.² RANZCOG recommends that modes of delivery should not be altered – decisions regarding caesarean section should be made for the usual obstetric indications.
- Myth: The maternity team will manage the CHB.
- Fact: General practice offers opportunities to initiate testing, coordinate referrals, provide antenatal counselling and follow-up care for both mothers and infants.
Practical checklist for GPs
- Complete all three tests for pregnant women, every time – 1. HBsAg, 2. HBsAb, 3. HBcAb.
- Normalise hepatitis B screening in your practice – everyone should know their status and be offered vaccination if susceptible.
- Act on a positive HBsAg result – complete further testing (e.g. hepatitis B viral load, HBeAg and coinfections) and refer.
- Screen all sexual, close and household contacts of any positive case for hepatitis B, and vaccinate if susceptible.
- Ensure an updated hepatitis B viral load result is known by 28 weeks.
- Maintain communication and discuss neonatal prophylaxis with the maternity team and the mother.
- Ensure regular and lifelong monitoring for everyone with CHB.
Where to find help and more information
- WA STI & BBV Guidelines
- Hep B Hub WA – Hepatitis B Support for GPs
- ASHM Decision Making in Hepatitis B Toolkit
- ASHM Hepatitis B Toolkit – Hepatitis B in Pregnancy
- WA Statewide Maternity Shared Care Guidelines
- WA Department of Health – Immunisation schedule and catch-up vaccines
- Australian Immunisation Handbook – Hepatitis B
- Clinician Assist WA – Chronic Hepatitis B Pathway
References:
- Yao N, Fu S, Wu Y, et al. Incidence of mother-to-child transmission of hepatitis B in relation to maternal peripartum antiviral prophylaxis: A systematic review and meta-analysis. Acta Obstet Gynecol Scand. 2022;101(11):1197-1206. doi:10.1111/aogs.14448
- Shi Z, Yang Y, Wang H, et al. Breastfeeding of newborns by mothers carrying hepatitis B Virus: a meta-analysis and systematic review. Arch Pediatr Adolesc Med. 2011;165(9):837-846. doi:10.1001/archpediatrics.2011.72