Hu AQ, Cai QY, Zhang M, et al. - Researchers sought to determine the prevalence of overt and occult hepatitis B infection (HBI) among mothers and infants. In addition, they examined the effectiveness of vaccination against HBI based on transmission types. They enrolled a hospital-based cohort with 2,734 mothers and 330 mother-infant pairs. HBI was overall prevalent in 12.1% of mothers (330/2,734) with 10.4% for the overt type and 1.8% for the occult one. This suggests that pregnant women still exhibit the prevalence of overt and occult hepatitis B infection during the transition period in China. The effectiveness estimates of current neonatal vaccination against hepatitis B virus tended to improve following separation of occult hepatitis B infection from “healthy” individuals. The virus was mainly transmitted by pregnant women with overt hepatitis B infection, which resulted in an overt or occult infection in their infants. The key strategy suggested is intensive prenatal screening of hepatitis B surface antigen for pregnant women.