KC Choi, CL Wong, KM Ieong

Abstract

Aims: First: To evaluate the effectiveness of Hepatitis B vaccine (HepB Vaccine) and Hepatitis B immunoglobulin (HBIG) on preventing vertical transmission of hepatitis B virus from hepatitis B carrier mother. Second: To assess the effectiveness of HepB Vaccine in providing adequate immune protection. Methods: It is a retrospective study from 1st January 2009 to 31st December 2013 which includes newborns from hepatitis B carrier mother delivered at Centro Hospitalar Conde de Sao Januario (CHCSJ) hospital of Macau. There were total 1315 newborns involved in the study. Hepatitis B carrier status was defined as patient who has hepatitis B surface antigen (HBsAg) during blood test. According to CHCSJ hospital hepatitis B vaccination protocol, all subjects should receive both HBIG and first dose of HepB Vaccine during birth, followed by second and third dose of HepB Vaccine at first and sixth month of age. For preterm baby with birth weight less than 2 kg, an additional dose of HepB Vaccine was required during second month of age. Blood test for HBsAg and hepatitis B surface antigen antibody (Anti-HBs) were performed after nine months of age to check for hepatitis B infection and immunity post vaccination. For non-infected subjects who did not develop adequate immune protection, a second course (three doses) of HepB Vaccine will be offered. Results: Out of the 1315 subjects, only 980 subjects had post vaccination blood test and HepB Vaccine given according to CHCSJ hospital hepatitis B vaccination protocol. Therefore, hepatitis B vertical transmission rates and post vaccination immune protection can only be assessed on the 980 subjects. Twenty-two out of 980 subjects were tested positive for HBsAg. That equals to an overall vertical transmission rate of 2.24% (95% confidence interval 1.29 to 3.18%). As an additional finding, based on the 570 subjects' mothers who had hepatitis B envelope antigen (HBeAg) tested, 176 were positive for HBeAg. The vertical transmission rate for HBeAg positive mothers were much higher reached 12.5% (95% confidence interval 7.5 to 17.5%). Eight hundred and sixty-four out of 980 babies developed adequate immune protection (as defined by antibodies level more than 10 mIU/ml) from hepatitis B virus after first course of HepB Vaccine. For the remaining 94 babies without adequate protection, 74 agreed to have second course of HepB Vaccine. However, only 29 babies had antibodies level tested after vaccination and follow up blood test revealed all of them to have immune protection. Conclusion: Active and passive immunisation with HepB Vaccine and HBIG for newborns of hepatitis B carrier mother are highly effective in preventing vertical transmission of hepatitis B virus and also provide adequate immune protection for most subjects. For subjects who did not develop adequate immune protection after first course of HepB Vaccine, it is worth giving a second course of HepB Vaccine. The compliance rate to CHCSJ hospital hepatitis B vaccination programme is not satisfactory and improvement has been made after the study period. Follow up study will be needed in the future to look for any improvement in compliance rates.