Impact of timing on protection of combined immunoprophylaxis in preventing mother-to-child transmission of hepatitis B virus: a retrospective study

Objective: To evaluate the impact of timing combined immunoprophylaxis on mother-to-child transmission (MTCT) of the hepatitis B virus (HBV) in pregnant women living with hepatitis B. Methods: A retrospective cohort study was included HBsAg-positive pregnant women who delivered full-term at Tianjin Third Central Hospital from January 2019 to December 2021. The objective of this study is to determine whether early administration of hepatitis B immune globulin (HBIG) and the first dose of hepatitis B vaccination after birth can further improve protection. Result: A total of 694 pregnant women living with hepatitis B were included; 93 infants from these mothers were lost to follow-up [including moving (n = 21), emigrating (n = 26), changing contact information (n = 27), and other reasons (n = 19)], leaving 601 infants for analysis. The incidence in babies born to mothers with hepatitis B was 1.50% (9/601). Based on the different timing of combined immunoprophylaxis administration after birth, 601 infants were divided into two groups (within 2 h and within 2-12 h). The incidence in babies born to mothers with hepatitis B were 0.32% (1/308) and 2.73% (8/293) for infants who received combined immunoprophylaxis within 2 h and between 2 and 12 h of birth, respectively (p = 0.037). The infection incidence of infants born to HBeAg-positive mothers and HBeAg-positive mothers who did not receive antiviral treatment during pregnancy was lower in the 2-h group compared to the 2-12 h group (0.72% vs. 5.84%, p = 0.04 and 1.20% vs. 9.46%, p = 0.047). Conclusion: Using combined immunoprophylaxis as soon as possible (within two hours of birth) may protect against MTCT of HBV more.