Residual risk of hepatitis B virus (HBV) mother-to-child transmission and gaps in HBV care cascades among pregnant women in The Gambia: the INFANT-B study

Abstract

Background Elimination of hepatitis B virus (HBV) is not achievable without prevention of mother-to-child transmission (PMTCT). In its 2024 guidelines, the WHO guidelines identified major research gaps on HBV MTCT in Africa. Aims Following the implementation of an antenatal HBV screening in The Gambia, we estimated the rate of HBV MTCT and the peripartum care cascade among pregnant women. Methods multicentre, non-randomised interventional study in Gambian antenatal clinics. Following mass and individual sensitisation, consecutive pregnant women were offered HBV testing and blood collection for further retrospective HBV MTCT risk assessment. HBsAg-positive mothers and their babies were prospectively followed up to 6-9 months post-partum. The primary endpoint was the rate of HBV MTCT defined by the proportion of HBsAg-positive babies. Results Between 2019 and 2022, 9,697/9,708 (99.9%) pregnant women accepted HBV screening; 449/9,697 tested positive (HBsAg prevalence:4.6% (95%CI:4.2-5.1)). Among 428 traceable live births, 216 (49.6%) babies were successfully tested for HBV; 6/216 were positive giving a 2.8% rate of MTCT (1.1-6.2). Major gaps in the HBV prevention and care services were identified: 64% of newborns did not receive HBV birth-dose vaccine, 25% of HBsAg-positive pregnant women refused to give blood for further risk stratification, and 62% were not linked to care after delivery. A small proportion (<2%) of women were eligible for postpartum treatment according to the 2017 EASL and 2024 WHO guidelines. Conclusion In The Gambia, the residual risk of HBV MTCT exceeds the elimination absolute target. Strategies to improve the peripartum and post-partum HBV care cascade are urgently needed.