ABSTRACT
Background & Aims: Peripartum prophylaxis (PP) with tenofovir disoproxil fumarate (TDF) is the standard of care to prevent mother-to-child transmission of chronic hepatitis B (CHB) infection in mothers who are highly viremic. We investigated the maternal and infant outcomes in a large Chinese cohort of TDF-treated CHB pregnant participants. Methods: In this prospective study, treatment-naive mothers with CHB and highly viremic (HBV DNA ≥200,000 IU/ml) but without cirrhosis were treated with TDF at 24-28 weeks of pregnancy. In accordance with Chinese CHB guidelines, TDF was stopped at delivery or ≥4 weeks postpartum. Serum HBV DNA and alanine aminotransferase were monitored every 6-8 weeks to determine virological relapse (VR). Infants received standard neonatal immunization, and HBV serology was checked at 7-12 months of age. Results: Among 330 participants recruited (median age 30, 82.7% HBeAg+, median HBV DNA 7.82 log IU/ml), TDF was stopped at delivery in 66.4% and at ≥4 weeks in 33.6%. VR was observed in 98.3%, among which 11.6% were retreated with TDF. Timing of TDF cessation did not alter the risk of VR (99.0 vs. 96.9%), clinical relapse (19.5 vs. 14.3%), or retreatment (12.6 vs. 10.1%) (all p > 0.05). A similar proportion of patients developed alanine aminotransferase flare five times (1.1 vs. 2.1%; p = 0.464) and 10 times (0.5 vs. 0%; p = 0.669) above the upper limit of normal (ULN) in the early withdrawal and late withdrawal groups, respectively. No infants developed HBsAg-positivity. Conclusions: PP-TDF and neonatal immunization were highly effective in preventing mother-to-child transmission of HBV in mothers who are highly viremic. Timing of cessation of PP-TDF did not affect the risk of VR or retreatment. Impact and Implications: In pregnant mothers with chronic hepatitis B infection who are started on peripartum tenofovir to prevent mother-to-child-transmission (MTCT), the optimal timing for antiviral withdrawal during the postpartum period remains unknown. This prospective study demonstrates that stopping tenofovir immediately at delivery, compared with longer treatment duration of tenofovir, did not lead to an increased risk of virological relapse, retreatment, or transmission of the virus to the baby. Shortening the duration of peripartum antiviral prophylaxis from 12 weeks to immediately after delivery can be considered. The immediate withdrawal of peripartum tenofovir, combined with standard neonatal immunization schemes, is 100% effective in preventing MTCT among pregnant mothers with CHB who are highly viremic, with a high rate of vaccine response in infants.
ABSTRACT
Solar-driven CO2 conversion to multicarbon (C2+) products has emerged as a key challenge, yet this calls for a systematic investigation on the overall reaction process and mechanism at an atomic level based on the rational design of highly selective photocatalysts. Herein, we report the synthesis of compact Bi2S3/CdS heterostructures via facile cation exchange, by which a unique pathway of CO2-to-C2H4 photoconversion is achieved. Specifically, the BCS-30 shows an optimal C2H4 production rate of 3.49 µmol h-1 g-1 based on the regulation of band structures and energy levels of photocatalysts by controlled growth of Bi2S3 at CdS surface. Both experimental and theoretical results (DFT calculations) identify Bi atoms as new catalytic sites for the adsorption of CO* and formation of *CO-*CO dimers that further hydrogenate to produce ethylene. Overall, this work demonstrates vast potentials of delicately designed heterostructures for CO2 conversion towards C2+ products under mild photocatalytic conditions.