Residual Risk of Hepatitis B Virus Mother-to-Child Transmission and Gaps in Care Cascades Among Pregnant Women in the Gambia: The INFANT-B Study.

Abstract

Elimination of hepatitis B virus (HBV) is not achievable without prevention of mother-to-child transmission (MTCT). In its 2024 guidelines, the World Health Organization identified major research gaps on HBV MTCT in Africa. Following the implementation of antenatal HBV screening in The Gambia, we estimated the rate of HBV MTCT and the peripartum care cascade among pregnant women. This multicenter nonrandomized interventional study was conducted in urban and rural antenatal clinics in The Gambia. Following mass and individual sensitization, consecutive pregnant women were offered HBV testing and blood collection for further retrospective HBV MTCT risk assessment including HBV DNA viral load and HBeAg serology. HBsAg-positive mothers and their babies were prospectively followed up to 6 to 9 months postpartum. The primary end point was the rate of HBV MTCT defined by the proportion of HBsAg-positive babies. Between 2019 and 2022, 9697 of 9708 (99.9%) pregnant women accepted HBV screening; 449 of 9697 tested positive (hepatitis B surface antigen [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 of 216 were HBsAg positive, giving a 2.8% rate of MTCT (95% CI, 1.1%-6.2%). Major gaps in 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 guidelines of the European Association for the Study of the Liver and the 2024 guidelines of the World Health Organization. In The Gambia, the residual risk of HBV MTCT exceeds the elimination absolute target. Strategies to improve the peripartum and postpartum HBV care cascade are urgently needed.