Immune responses of infants born to HBsAg positive mothers after combined passive immunoprophylaxis and active immunoprophylaxis / 中华传染病杂志

ABSTRACT

Objective To evaluate the immune responses and its dynamic changes of the babies born to hepatitis B surface antigen (HBsAg) positive mothers after combined passive immunoprophylaxis and active immunoprophylaxis. Methods Two hundred and forty-nine infants born to HBsAg positive mothers were enrolled. All of these infants have received both passive immunoprophylaxis by injecting hepatitis B immunoglobuin (HBIG) and active immunoprophylaxis by vaccinated with hepatitis B vaccine simultaneously 12 hours after birth. After that, all infantscompleted the whole vaccination program. The titers of serum HBsAg and hepatitis B surface antibody (HBsAb) of the infants were checked at 7, 12, 24 and 36 months after birth. The data was analyzed by chi square test. Results Infants born to HBsAg positive mothers showed various immune response modes. The no response rate, low response rate and strong response rate were 8.0% (20/249),11.7% (29/249) and 80.3% (200/249) respectively in the 7-month infants, which were 10.8% (12/120), 26.7% (32/120) and 62.5% (75/120) respectively in 12-month infants. The results from further follow-up showed that no response rate, low response rate and strong response rate were 14.8% (4/27), 33.3% (9/27) and 51.9% (14/27) respectively in the 24-month babies and were 14.3 (1/7), 28. 6% (2/7) and 57.1% (4/7) respectively in the 36-month babies. There were statistically significant difference between the 7-month infants group and other groups (x2= 21.98,P＜0.01). The HBsAb titers of high-response infants group declined over time. The infants with higher antibody titers tended to not decline or decline more slowly. In infants who have even achieved HBsAb titers higher than 1000 mIU/mL, 57.6% (19/33) of them showed decreased titers in 36 months. The titer decrease peaked at 24 month after birth (57.9%, 11/19). In infants who have achieved HBsAb titers of 100 to 1000 mIU/mL, 73.8% (31/42) of them showed decreased titers in 36 months. The titer decrease peaked at 12 month after birth (54.8%, 17/31). HBsAg positive infants usually showed no response at 7 month, who accounted for 70% (14/20,x2 = 128.61, P＜0.01) of all no response infants. Ninety-nine percent (189/191) of HBsAg negative infants showed strong responses. The infants born to both HBsAg positive and hepatitis B e antigen (HBeAg)positive mothers tended to show no response. However, the difference between these infants and others was not statistically significant (9.1% vs 5.5%,x2 =0.24,P＞0.05). Conclusions The immune responses of infants born to HBsAg positive mothers after combined passive and active immunoprophylaxis change over time. The non-response status is usually found in HBsAg positive infants. HBsAg negative infants usually show strong response. Infants born to both HBsAg positive and HBeAg positive mothers tend to show low response. It is recommended to follow standard immunoprophylaxis procedure. The follow-up and active monitor are very important during 7 months to 2 years after birth.