[A follow-up study on the efficacy of hepatitis B immunoglobulin combining hepatitis B vaccine in infants born to HBsAg positive mothers].

Objective: To study the efficacy of hepatitis B immunoglobulin (HBIG) combining hepatitis B vaccine in high risk infants born to HBsAg positive mothers through a follow-up study program.

Methods: 184 infants (4 twin pairs) born to HBsAg carrier mothers who were consecutively recruited from December 2002 to August 2004 were followed. Major HBV serologic markers in all infants were detected by enzyme-linked immunosorbent assay (ELISA) when they were at birth, at 7th, at 24th and at 36th months.

Results: 7 of the 184 infants were HBsAg positive at birth, making the transplacental intrauterine infection rate of HBV as 3.80% (7/184). 125 infants were followed up at 7th months and 108 infants were followed up at 24th and 36th months. Only 2 of the 7 infants born to HBsAg-positive and HBeAg-positive mothers were persistently sera positive for HBsAg, making the chronic infection rate of HBV as 28.57%. The other 140 infants were HBsAg negative during t he follow-up period. The rate o f detectable anti-HBs i ninfants was 7.02% at birth. After infants were immunized by HBIG combining hepatitis B vaccine, the anti-HBs-positive rate reached 92% at 7th months, and gradually descended thereafter. 72.04% of the infants at 24th and 60% at 36th months showed detectable levels of anti-HBs. There was significant correlation between the produce of anti-HBs in infants and HBsAg-positive at birth while HBsAg-positive and HBeAg-positive in mothers did not relate to the produce of anti-HBs in their infants. Of 39 infants born to HBsAg-positive and HBeAg-positive mothers, 25 showed detectable levels of HBeAg. During the follow-up peirod, HBeAg was still detectable in 2 infants who were also HBsAg positive and the others all became HBeAg-negative but no infant became HBeAg-positive.

Conclusion: The efficacy of HBIG combining hepatitis B vaccine in high risk infants was fine.