海南省新生儿接种乙肝疫苗阻断母婴传播影响因素调查

Investigation of factors influencing interrupting transmission of hepatitis B from mothers to the newborns by vaccination of the newborns in Hainan Province

目的研究海南省影响新生儿接种乙肝疫苗阻断母婴传播的因素，为制定乙肝控制策略提供依据。方法采取按容量比例概率（PPS）和机械抽样方法，调查12～24月龄儿童及其母亲和小学一年级新生乙肝疫苗免疫史，采集被调查儿童静脉血3ml，同时采集12—24月龄儿童母亲血5ml，用ELISA法检测儿童HBsAg携带状况和母亲乙肝病毒感染状况。结果全省抽查12—36月龄儿童666名，一年级新生528名，母亲501名。儿童乙肝疫苗首针及时率分别为91．59％、41．48％；及时接种儿童HBsAg携带率为1．21％，不及时接种者为7．12％；及时接种儿童中HBsAg携带率12～36月龄为0．49％，一年级新生为3．2．％；HBsAg携带率全程接种儿童为2．35％，未接种儿童为11．67％；母亲中HBsAg、HBeAg双阳性所生儿童HBsAg携带率最高，为13．79％，HBsAg单阳性所生儿童为1．52％，HBsAg阴性母亲所生儿童为0．24％，三者差异有显著统计学意义（x2=56．76，P〈0．01）；新生儿乙肝母婴阻断率为94．16％，母亲HBsAg单阳性者阻断率为98．32％，HBsAg、HBeAg双阳性者阻断率为84．68％。12—36月龄儿童中携带HBsAg的均为母亲双阳或单阳者，6名携带HBsAg儿童及时接种率仅为16．67％。结论海南省将乙肝疫苗纳入儿童免疫规划后有效阻断了母婴传播。对母亲HBsAg阳性，特别是双阳性母亲所生携带HBsAg儿童，虽不能排除宫内感染的可能性，但不及时接种乙肝疫苗是主要因素。

Objective To investigate the factors influencing interrupting tranmisssion of hepaitis B from mothers to the newborns by immunization of the newborns with hepatitis B vaccine and provide evidence for making control strategy. Methods Infants aged 12-24 months and primary school pupils were sampled by probability-proportional-to-size sampling （PPS） and randomized mechanical sampling. The history of hepatitis B vaccine vacciantion was surveyed and 3ml or 5ml navel blood was collected from the infants and their mothers.to detect hepatitis B virus infection by ELISA. Results There 666 infants aged 12-36 months, 501 mothers and 528 primary school pupil were investigated. The rate of first dose of hepatitis B vaccine infants aged 12-36 months and the pupils were 91.59% and 41.48%. The HBsAg carrying rate in vaccinated infants was 1.21% and that of those without vaccination was 7.12%. HBsAg carrying rates in infants aged 12~36 months and pupils vaccinated in time was 0.49% and 3.2%.The HBsAg carrying rate in infants with full course vaccination was 2.35% and 11.67% in those withlout vaccination. The HBsAg Carrying rate in the infants born by mothers positive for HbsAg and HbeAg was the highest （13.79%）, while the HBsAg carrying rates in the infants born by mothers positive for HbsAg and negative for HbsAg were 1.52% and 0.24%, showing significant differences （x^2=56.76,P〈0.01）. The hepatitis Btransmission blocking rates in the newborns, in mothers positivefor HbsAg, in mothers positive both for HbsAg and HbeAg were 94.16%, 98.32% and 84.68%. The HBsAg carriers of infants aged 12-36 months were all born by mothers either positive both for HBsAg and HBeAg or positive for HBsAg. The timely vaccination rate of six infants HBsAg carriers was only 16.67%. Conclusion The transmission of hepatitis B from mothers to infants has been successfully interrupted after the integration of hepatitis B vaccine vacination into expanded child immunization program in this province. The cause of high HBsAg carrying rate in infants born by mothers positive for HBsAg or positive both for HBsAg and HbeAg were mainly due to failed timely immunization of hepatitis B vaccine, though the possibility of vertical transmission during pregnancy can not be excluded.