A large population-based epidemiological investigation and follow-up study of hepatitis B virus infection in northwest China
METHODS: The cross-sectional survey and case-control study were carried out from 2010 to 2012, with participants selected by stratified random cluster sampling. A standard questionnaire was developed for collecting demographics and risk factors. Sera were tested for HBV biomarkers by ELISA. HBsAg positive individuals were followed up per 6 months. Taylor Series Linearization method was used to calculate the weighted prevalence rate, weighted multiple logistic regressions were calculated the adjusted odds ratio (OR) and 95%CI.
RESULTS: There were 28044 people who participated in the survey, and 2051 were positive for HBsAg, in which 1636 (79.76%) were followed up. The prevalence for HBsAg, anti-HBs and anti-HBc were 7.31% (95%CI: 6.26%-8.12%), 49.07% (95%CI: 45.50%-52.65%) and 43.90% (95%CI: 40.38%-47.41%), respectively. The household contact with HBV current infector (OR=2.62, 95% CI: 2.32-3.03) and a history of traumatic beauty (OR=1.20, 95% CI: 1.15-1.35) were risk factors for HBsAg carriers in the general population. The delayed injection of first dose of HBV vaccine after premature birth and/or low birth-weight was a new finding risk factor for mother-to-infant transmission (OR=9.73, 95% CI: 1.78-53.21). The annual HBsAg seroclearance and seroconversion rates, and HBeAg seroconversion rate were 3.86% (95%CI: 2.66%-5.41%), 1.79 % (95%CI: 0.98%-2.98%) , 7.28% (95%CI: 3.55%-13.01%) per 100 person-years, respectively.
CONCLUSIONS: HBV infection remains a serious public health challenge in northwest China. HBsAg and HBeAg natural seroconversion should be considered for long-term antiviral therapy effect evaluation. In order to block mother-to-infant transmission more effectively and avoid potential consequence of doctor-patient disputes, HBV prevention guideline should make it clear that premature and low birth-weight infants need to receive HBV vaccine after birth in 24 hours.