Objectives: Overt and occult hepatitis B infection (HBI) among mothers and infants were investigated, and the effectiveness of vaccination against HBI was evaluated based on transmission types. Methods: A hospital-based cohort was built with 2,734 mothers and 330 mother-infant pairs. Their demographic data were collected. Serological HBV markers, nested-PCR for HBV genes, viral load detection, and phylogenetic analysis were done. Results: The overall prevalence of HBI among mothers was 12.1% (330/2,734), with 10.4% for the overt type and 1.8% for the occult type. In 330 out of 1,650 (20%) mother-infant pairs, the overall, type-I (from overt mother to overt infant), type-II (from overt mother to occult infant), and type-Ⅲ (from occult mother to occult infant) transmissions were 1.9% (1/54), 5.6% (3/54) and 0.0% (0/7). The refinement of HBI classification improved the estimate of vaccine effectiveness against HBI from 74.4%–80.9% to 94.4%, which was more prominent for type-II. One mother-infant pair with type-II transmission shared nearly identical complete sequences. However, the high rate of lost-to-follow-up could not be ignored. Conclusions: During the transition period, HBV is mainly transmitted from the overt type of HBI mother to infant. Intensive prenatal screening for mothers is vital.
Full Text via ClinicalKey 
Full Text Finder