| Background: Hepatitis B is a serious public health problem throughout the world.It is eastimated up to350millon people throuthout the world are chronic HBVinfection, and1millon of them died of chronic hepatitis, cirrhosis, andhepatocellular carcinoma each year. China is a high prevalent area of HBV. It isestimated that there are93million HBsAg carriers and25million chronic HBVinfected people in China. Without immunoprophylaxis, more than90%of infantswho were infected by their HBeAg/HBsAg positive mothers will develop chronicHBV infection, which is a major cause of cirrhosis and liver cancer. In recentyears, some strategies have been used to interrupt HBV mother-to-childtransmission, such as routine hepatitis B immunization program and theapplication of HBIG in newborn infants. In2002, China started integratinghepatitis B vaccine into Expanded Programme on Immunization (EPI), withemphasising on providing a timely birth dose (within24h of birth). The cost ofvaccine was paid by the government. Since the strategy has been implemented8 years in Wuwei city, its effectiveness on HBV mother-to-child transmission hasnot been reported, which is important to establish a more effective prevention andcontrol strategy for HBV infection.Objective: To evaluate the present situation and possible risk factors of HBVmother-to-child transmission after8years of the implementation of routinehepatitis B immunization program in the northwest of China.Methods:(1) Two hundred and twenty-one HBsAg carrier mothers and their247childrenwere finally recruited in Wuwei city, Gangsu province, China from2008to2010.A standard questionnaire was developed for collecting information of themothers and children, including demographic data, medical andreproductive history, family history of HBV infection, history of threatenedabortion, history of preterm delivery, history of breast feeding, medicaltreatment and vaccination of the children. Serum samples were taken fromthose HBsAg carrier mothers and their children A single lot of enzyme-linkedimmunosorbent assay (ELISA) reagents was used for the initial testing forHBsAg, anti-HBs, HBeAg and anti-HBc. All the specimens were quantifiedfor HBV DNA by using diagnostic kit (PCR-Fluorescent probing). Childrenwho had detectable HBsAg or HBV DNA were considered to be HBV infection.Children validated as having HBV mother-to-child transmission wereselected as cases. The rest children were matched as controls. Conditionallogistic regression model was used to identify potential risk factors of HBVmother-to-child transmission.(2) In this study, we surveyed the premature infants and, and collectedinformation such as newborn information, maternal labor information, andinformation of the1st dose of HBV vaccine injection. In order to give a comprehensive evaluation of the1st dose of HBV vaccine immunization inpremature and low birth-weight infants.Results：(1) Of the247children born to HBsAg carrier mothers,8(3.24%) were HBsAgpositive,15(6.07%) were HBV DNA positive. The rate of HBV mother-to-childtransmission was7.29%(18/247).185(74.90%) children were anti-HBs positive,91(36.84%) children were anti-HBc positive.(2) The univariate analysis and multivariate analysis showed that maternal HBVDNA positive (OR=4.83,95%CI:1.38-16.98, P=0.0140), the delayed injectionof1st dose of HBV vaccine after premature birth (OR=9.73,95%CI:1.78-53.21,P=0.0087) and the missing use of HBV vaccine (OR=8.29,95%CI:1.42–48.23,P=0.0186) were significantly associated with an increased risk for HBVmother-to-child transmission.(3) Of346premature infants, the1st dose of HBV vaccine inoculation rate was97.98%(339/346), the timely inoculation rate was30.35%(105/346); of386low-birth weight infants, the1st dose of HBV vaccination inoculation rate was100%(386/386), the timely inoculation rate was11.66%(45/386).The mean timeof delayed days for the1st dose of HBV vaccination was15.21±13.02(rangefrom2-69). Additionally, there was a linear correlation between the birth week ofinfants and delayed days for the1st dose of HBV vaccination (r=-0.384，P<0.001).The same correlated relationship was found between the birth week ofinfants and delayed days for the1st dose of HBV vaccination (r=-0.384，P<0.001).Conclusions：(1) The rate of mother-to-child transmission of HBV was still high in thenorthwest of China. (2) Besides the positivity of maternal HBV DNA and the missing of HBVvaccination after birth, premature birth was also a possible independent riskfactor for HBV mother-to-child transmission. Raising the vaccination dose ofHBV vaccine and joint HBIG in24hours after birth is necessary for childrenborn to HBsAg positive mothers, including for the premature infants.(3) The timely inoculation rate of the premature and low birth-weight infants waslow in Wuwei, Gansu. The relative medical departments should get moreknowledge about the HBV vaccine inoculation to improve thr situation. The HBVprevention and treatment guidelines should make it clear that all of the new borninfants need to receive HBV vaccine injection after birth in24hours, includingthe premature and low birth-weight infants. |
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