1005 Prevention of Hepatitis B (HBV) mother-to-child transmission (MTCT)

According to World Health Organisation reports there are 350 million chronic HBV carriers worldwide, and MTCT accounts for approximately half of them. Transmission may take place during pregnancy, labour and/or after labour. WHO, CDC and others have therefore advocated a programme involving both hepatitis B immunoglobulin (HBIG) and early vaccination of the neonate (HBvac). Despite this, some 1-8% of the children of HBV carrier mothers suffer from HBV infection in early life, this most likely because infection had already taken place during pregnancy. Several studies have been done to address the latter issue, with researchers administering HBIG during late pregnancy, with or without the postnatal joint HBIG-HBvac protocol. However results have been variable, and for this reason researchers in the US and China undertook a meta-analysis, comparing the pre- and postnatal programme results against postnatal alone. Utilising results from 37 eligible studies involving 5900 newborns of asymptomatic HBsAg-positive mothers, the authors found intrauterine infection rate and newborn protection rate to be significantly reduced by the antenatal HBIG injections. These injections, usually involving doses of 200IU (with a few at 100 or 400IU), were given once per month from 28 weeks onwards for a total of three doses. The antenatal HBIG group’s lower infection rate (as measured by HBsAg) was confirmed by an odds ratio of 0.22; 95%CI 0.17,0.29, while measuring infection rate in terms of HBV DNA gave an odds ratio of 0.15; 95%CI 0.07,0.30. The higher protection rate in the antenatal group (as measured by HBsAb) was confirmed by an odds ratio of 11.79; 95%CI 4.69,9.61. The same effectiveness trend was shown at 9-12 months. The HBIG is thought to act via transfer of antibody to the foetus and passive immunity rather than by mopping up maternal virus. There is a note of caution in these results in that the meta-analyses showed significant publication bias and effectiveness might be overstated.

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Int J Infect Dis (2010) doi:10.1016/j.ijid.2009.09.008
Wkly Epidemiol Rec 2004;79: 255-63
J Hepatol 1994; 34: 392-5