Background/Aims
Hepatitis B virus (HBV) mother-to-child transmission (MTCT) remains a global health concern, with over 90% of perinatal infections leading to chronic HBV. To evaluate long-term trends in MTCT rates and associated factors within Korea’s national program.
Methods
Population-based cohort study using linked data from the Perinatal Hepatitis B Prevention Program (PHBPP) and National Health Insurance Service in Korea. The study included HBsAg-positive mother-infant pairs with post-vaccination serologic results from 2002 to 2021.
Results
Among the 154,478 mother-infant pairs, the overall MTCT rate after prophylaxis was 2.3%. Antiviral use lowered MTCT rates (0.9% vs. 2.4%) particularly in HBeAg-positivity (1.0% vs. 5.9%; adjusted odds ratio [aOR] 0.21; 95% confidence interval [CI] 0.14–0.32). Lower MTCT rates were observed for cesarean section vs. vaginal delivery (1.9% vs. 2.6%; aOR 0.78; 95% CI 0.73–0.84) and breastfeeding vs. formula feeding (1.8% vs. 2.8%; aOR 0.65; 95% CI 0.56–0.76). Annual MTCT rates decreased from 3.6% (2002–2005) to 1.3% (2018–2021). Antivirals reduced MTCT rates; initiation at 14–27 weeks (0.39%), or 28–32 weeks (0.44%) vs. ≥33 weeks (1.47%); postpartum continuation (0.55%) vs. antepartum discontinuation (1.44%); use ≥61 days (0.51%) vs. 1–60 days (1.67%). Lower MTCT risk was associated with maternal (old age, high income) and infant (female sex, preterm birth) factors.
Conclusions
This comprehensive analysis of the PHBPP in Korea demonstrates that the use of antivirals, breastfeeding, and cesarean section, combined with conventional immunoprophylaxis, has significantly reduced MTCT rates. These results are crucial for global HBV elimination and can help to guide HBV MTCT prevention strategies.

Background/Aims
There have been numerous efforts to reduce mother-to-child transmission (MTCT) of hepatitis B virus (HBV) with antiviral agents during pregnancy. However, there are limited data regarding the outcomes of pregnant women after delivery. This study was performed to evaluate the efficacy of antiviral agents in preventing MTCT of HBV and maternal long-term outcomes.
Methods
The HBV-infected pregnant women treated with antiviral agents to prevent MTCT were retrospectively reviewed. Forty-one pregnant women who received telbivudine or tenofovir during late pregnancy (28-34 week) were analyzed. Hepatitis B virus surface antibody (HBsAb) positivity was tested in 43 infants after 7 months of birth. Eleven mothers were followed >1 year after delivery.
Results
The mean HBV DNA titer before antiviral therapy was 8.67 (6.60–9.49) log copies/mL, and the median age at delivery was 32 years (range, 22–40). Eleven patients were treated with tenofovir and 30 with telbivudine. The median duration was 57 days (range, 23–100), and the median HBV DNA titer at birth was 5.06 log copies/mL (range, 2.06–6.50). Antiviral treatments were associated with significant HBV DNA reduction (P<0.001). Among 43 infants (two cases of twins), HBsAb was not detected in two, subsequently confirmed to have HBV infection. Biochemical flare was observed in two of 11 mothers followed >12 months, and an antiviral agent was administered.
Conclusions
Antiviral treatment during late pregnancy effectively reduced MTCT. Long-term follow-up should be required in such cases. In addition, given that maternal biochemical flare occurred in 18% of mothers, re-administration of antiviral agents might be required.