Preventing perinatal transmission

Post-exposure prophylaxis is particularly recommended for babies born to HBsAg positive mothers, including mothers who have had acute hepatitis B during pregnancy. Hepatitis B infection can be transmitted from infected mothers to their babies by perinatal transmission, conferring a high risk of chronic disease.

Perinatal transmission can be effectively prevented in over 90% of cases by appropriate vaccination starting at birth of all infants born to HBsAg positive mothers. Department of Health guidelines recommend that all pregnant women should be offered screening for hepatitis B infection during each pregnancy. If infection is found, confirmatory testing and testing for HBeAg or anti-HBe should follow. All babies born to these mothers should receive a complete course of vaccine.

Babies born to mothers who are HBsAg positive and HBeAg-positive (or with no confirmation of the presence of anti-HBe) should receive HBIG as well as active immunisation. Similarly, babies born to mothers with acute hepatitis B or known to have HBV DNA level equal to or above 1X106 IU/ml and babies weighing less than 1500g born to mothers who are HBsAg positive, should receive both hepatitis B immunoglobulin and immunisation.

HBIG should be given, immediately after delivery or within 24 hours and needs to be ordered well in advance of the birth. It may be given simultaneously with vaccine but at a different site.

For post-exposure prophylaxis in babies born to HBV-infected mothers, the accelerated immunisation schedule should be used. Babies receive a dose of vaccine at birth followed by doses at one and two months of age and a fourth dose at 12 months.

Testing for HBsAg at one year of age, at the time of the fourth dose, is required to identify any children for whom the intervention has failed and who have become carriers. These children will require on-going assessment and further management.

Women with high viral loads (i.e. HBV DNA > 107-8 IU/ml) and in cases where transmission to a previous infant has occurred during childbirth, may be at risk of transmission despite HBV vaccination and HBIG use and can be considered for antiviral therapy from 32 weeks of pregnancy. There is some evidence that a short treatment can reduce viral load and therefore the risk of transmission. If the apparent safety and lack of teratogenicity of nucleoside analogues in pregnancy can be verified, treatment of the mother either throughout, or in the third trimester of pregnancy to reduce mother infant transmission may be recommended. Ongoing disease management in the mother has also to be taken into account.