Objective To study the efficacy and possible mechanism of active and passive immunization during pregnancy in preventing intrauterine HBV infection.

目的探讨孕妇主动与被动联合免疫预防乙型肝炎病毒（H BV）宫内感染的作用和机理。

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Objective to investigate the effect of passive immunization of fetus by injection of HBIG to mothers for prevention of HBV intrauterine infection.

目的探讨经母亲对胎儿行被动免疫在预防乙型肝炎病毒(HBV)宫内感染中的作用。

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The effect of medicament-control, how to use vaccine controlling HCMV infection and related disease, and the role of passive immunity in controlling HCMV infection were introduced in detail.

阐述了使用药物控制HCMV感染的效果，疫苗在控制HCMV感染及引发疾病方面的作用及通过被动免疫控制HCMV感染的现状与进展。

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He said estimates suggested that each year passive smoking in children accounted for more than 20, 000 cases of lower respiratory tract infection, 200 cases of bacterial meningitis, and 40 sudden infant deaths.

BBC: Smoking in the car 'breaks toxic limit'