Epidemiological Study On Intrauterine HBV Infection

[BACKGROUD]The prevalence of HBV is high in China where 10% of people are chronically infected with hepatitis B virus, leading to a serious public health problem. 30% to 50% of people with chronic infection may result from perinatal transmission. HBIG immediately after delivery in combination with recombinant vaccine results in a higher-than-90% level of protection against perinatal acquisition of HBV. 5% to 10% of infants were still infected by HBV from mothers, despite immunoprophylaxis. Failure of passive and active immunoprophyxis in this setting may be the result of in utero transmission of HBV. For this reason, Elucidation mechanisms, risk factors of intrauterine HBV infection, and evolution of the dynamic change of seral HBV markers in infants are important for prevention of hepatitis B infection. [AIM]1. To probe into the risk factors of HBsAg positive at birth in infants born to HBsAg carrier mothers by case-control study.2. To investigate the dynamic changes of HBsAg and HBeAg in infants born to HBsAg carrier mothers by follow-up study, and to evaluate its clinical and epidemiological significances.