Passive and Active Immunization to Prevent Perinatal Vertical Transmission in Infants Born to HBsAg Carrier Mothers

Most of the perinatally infected infants from their HBsAg carrier mothers become chronic carrier and develop chronic liver disease. Prevention of vertical transmission is most important in elliminating hepatitis B virus infection. CDC recommended passive and early active immunization in neonatal infants born to HBsAg carrier mothers to prevent perinatal vertical transmission.

The author checked anti-HBs titer at 7~9 month of age in 112 infants who were born to HBsAg carrier mothers and were received HBIG 0.5cc at birth and 0.5cc Hepavax at 0, 1, 6 month of age by CDC recommendation and studied the preventive effect of passive and early active immunization.

The results were as follows :

1) Anti-HBs was positive in 98 infants(87.5%) and negative in 14 infants(l2.5%). Because 6 positive infants had anti-HBs below 10mIU/ml. only 92 infants(82.1%) had minimal protective anti-HBs.

2) Anti-HBs positive rate in infants of HBeAg (+) mothers was 77.8% (35/45) which was significantly lower than 94.0% (63/67) in infants of HBeAg(-) mothers(p<0.05).

3) Anti-HBs positive rate in infants of positive neonatal HBeAg was 77.8% (28/46) which was significantly lower than 92.1% (70/76) in infants of negative neonatal HBeAg(p<0.05).

4) Perinatal vertical transmission has occured in 2 infants of 14 anti-HBs(-) infants(14.3%). Among 8 anti-HBs(-) infants of HBeAg(+) mothers, HBsAg was perinatally transmitted in 2 infants(25%). Six anti-HBs(-) infants of HBeAg(-) mothers were not infected.

5) Among 7 anti-HBs(-) infants with positive neonatal HBeAg, 2 infants(28.6%) was perinatally infected. Seven other anti-HBs(-) infants with negative neonatal HBeAg were not infected.

6) The maximum titer of 98 anti-HBs(+) infants by passive and early active immunization was as follows; 6 infants:<10mIU/ml. 8 infants 11~100mIU/ml. 21 infants: 101~1000mIU/ml. 36 infants 1001~10000mIU/ml. 28 infants:>10000mIU/ml The anti-HBs titer was below 1000mIU/ml in 35.9% (35/98) of anti-HBs(+) infants.

In conclusion, the preventive effect of passive and early active immunization was not complete especially in HBeAg(+) infants whose mothers had HBeAg.