Analysis in hepatitis B vaccination,infection status,and related influencing factors in children ≤ 14 years old in Dali Bai Autonomous Prefecture

Objective To understand the status and influencing factors of hepatitis B vaccination and infection among children ≤14 years old in Dali Bai Autonomous Prefecture,evaluate the effect of hepatitis B vaccine （HepB） in immunization program,and provide evidence for improving prevention and control strategies. Methods Stratified cluster sampling was used to conduct a questionnaire survey and serum samples were collected in 7 617 permanent residents aged 8 months and older in Dali Bai Autonomous Prefecture from May to June in 2017 and 2018,and among them,4 000 children aged under 15 years were selected for analysis and evaluation. Results The vaccination coverage rate of HepB in the children under 15 years old was 99.20%,the timely first dose vaccination rate was 95.34%,and the whole course vaccination rate was 99.05%.Younger age （0-4 years） group (OR_vaccination=6.653,OR_{timely vaccination}=3.229,P<0.001,respectively) and hospital births (OR_vaccination=11.007,OR_{timely vaccination}=10.747,P<0.001,respectively) were protective factors for HepB vaccination and timely first dose vaccination.Birth in town （OR=0.112,P<0.001） was a risk factor for HepB vaccination,while Han nationality （OR=1.616,P=0.006） was a protective factor for the timely first dose vaccination.The positive rates of HBsAg and HBsAb were 0.15% and 72.28%,respectively.The positive rate of HBsAb was negatively correlated with age （r_s=-0.442,P<0.001） and time interval after the whole course vaccination （r_s=-0.443,P<0.001）.The timely first dose vaccination decreased the HBsAg positive rate （OR=0.097,P=0.007） and the short interval after whole course vaccination increase the HBsAb positive rate （OR=7.258,P<0.001）. Conclusion The children ≤14 years old in Dali Bai Autonomous Prefecture are in high vaccination level of HepB and low prevalence of HBsAg.The immune and prevention effects of HepB vaccine are significant.Improving hospital delivery rates and timely vaccination of HepB are important measures to prevent and control infection.