Perinatal transmission of hepatitis B virus: an Australian experience

Med J Aust. 2009 May 4;190(9):489-92. doi: 10.5694/j.1326-5377.2009.tb02524.x.

Abstract

Objective: To determine the rate of perinatal hepatitis B virus (HBV) transmission in an Australian setting and to identify maternal virological factors associated with highest risk of transmission.

Design, participants and setting: A prospective, observational study of perinatal transmission of HBV. Participants were pregnant women attending Sydney South West Area Health Service antenatal clinics who tested positive for hepatitis B surface antigen (HBsAg), and their babies. All babies were routinely offered hepatitis B immunoglobulin (HBIG) and HBV vaccination. Babies positive for HBsAg at 9-month follow-up underwent further virological testing, including HBV DNA sequencing. The study was conducted between August 2002 and May 2008.

Main outcome measures: HBV DNA levels and demographic characteristics of HBsAg-positive pregnant women; proportion of their infants with active HBV infection at 9-month follow-up; maternal characteristics affecting transmission rate; HBV DNA sequencing of infected infants and their mothers.

Results: Of 313 HBsAg-positive pregnant women, 213 (68%) were HBV DNA-positive and 92 (29%) were positive for hepatitis B "e" antigen (HBeAg); 138 babies born to HBV DNA-positive mothers were tested for HBV infection (HBsAg positivity) at about 9 months of age. Four cases of transmission were identified. All four mothers had very high HBV DNA levels (> 10(8) copies/mL) and were HBeAg-positive. Three of the four infants were infected with wild-type HBV strains, with identical maternal/infant isolates. The fourth mother-infant pair had an S gene variant, HBV D144E, which has been previously reported in association with vaccine/HBIG escape. (Unfortunately, HBIG was inadvertently omitted from the immunisation schedule of this infant.) Transmission rates were 4/138 (3%) from HBV DNA-positive mothers overall, 4/61 (7%) from HBeAg-positive mothers, and 4/47 (9%) from mothers with very high HBV DNA levels. No transmission was seen in 91 babies of mothers with HBV DNA levels < 10(8) copies/mL.

Conclusion: In this cohort, HBV perinatal transmission was restricted to HBeAg-positive mothers with very high viral loads.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Australia / epidemiology
  • DNA, Viral / blood
  • Female
  • Hepatitis B / blood
  • Hepatitis B / epidemiology
  • Hepatitis B / transmission*
  • Hepatitis B Surface Antigens / blood
  • Hepatitis B e Antigens / blood
  • Hepatitis B virus / genetics
  • Humans
  • Infant, Newborn
  • Infectious Disease Transmission, Vertical / statistics & numerical data*
  • Pregnancy
  • Pregnancy Complications, Infectious / blood
  • Pregnancy Complications, Infectious / epidemiology*
  • Viral Load

Substances

  • DNA, Viral
  • Hepatitis B Surface Antigens
  • Hepatitis B e Antigens