Long-term protection of infants against hepatitis B by neonatal immunoprophylaxis born from mothers infected with hepatitis B virus

Objective To evaluate the long-term efficacy of neonatal immunoprophylaxis in children born from mothers infected with hepatitis B virus (HBV), and to clarify whether a booster vaccination is required. Methods Totally 252 children of HBV infected mothers, who were negative for hepatitis B surface antigen (HBsAg) tested in Nanjing Drum Tower Hospital in 2012, were enrolled to participate in this study from July to September, 2017.Revaccination of hepatitis B vaccine was recorded and other relevant informations were collected.HBV serologic markers were detected in each child. Results Totally 198 children (78.6%) were followed up.They were (8.4±2.2)years old and 112 cases were boys.All 198 children were negative for both HBsAg and hepatitis B core antibody (anti-HBc). The overall positive rate of hepatitis B surface antibody (anti-HBs) (≥10 IU/L) was 65.7%.During period of 2012 to 2017, 53 children were boosted with hepatitis B vaccine.Their median anti-HBs titer in 2017 was higher than that in 2012 (327.95 IU/L vs.158.01 IU/L), and the difference was significant (Z=-4.480, P<0.05). The other 145 children were not revaccinated, their median anti-HBs titer was decreased from 214.19 IU/L in 2012 to 70.49 IU/L in 2017, and the difference was significant (Z=-6.575, P<0.05). Of 145 children who were not revaccinated, 25 cases had anti-HBs levels <10 IU/L and 120 cases ≥10 IU/L in 2012, and the other 47 cases also showed the antibody <10 IU/L in 2017, but none of them was infected with HBV. Conclusions Neonatal immunoprophylaxis in infants from HBV-infected can provide long-term protection against hepatitis B. The children with anti-HBs <10 IU/L are still immune to HBV and booster vaccination for them seems unnecessary. Key words: Hepatitis B virus; Hepatitis B vaccine; Neonatal immunoprophylaxis; Long-term protection