A large scale cohort study on the immunization effect of hepatitis B vaccine in Fujian province

Objective To evaluate the effectiveness of hepatitis B vaccination in Fujian province. Methods Based on the hepatitis B immunization strategy of China, a cohort study was designed, involving the population in Fujian province. The population under study was divided into natural exposure birth cohort before 1992 and the immunization birth cohort after 1992 (including voluntary vaccination cohort and standardized vaccination cohort). By cleaning the database of hepatitis B cases which directly reported through network and looked into the incidence and related death outcomes of acute hepatitis B from 2004 to 2017, the incidence levels of hepatitis B and immunization effects were analyzed and evaluated among different birth cohorts. Results During the observation period, the overall prevalence of hepatitis B in Fujian province was 44.594 per 100 000, with mortality rate as 0.010 per 100 000. The incidence of natural exposure cohort of birth was 56.885 per 100 000. The incidence of voluntary vaccination cohort of birth was 14.502 per 100 000. Compared with the voluntary vaccination cohort, the risk of hepatitis B increased significantly in the natural exposed cohort (RR=3.923), and the difference was statistically significant (P=0.000 7), with attributable risk as 42.383 per 100 000. The attributable risk ratio was 74.507. The population attributable risk ratio was 70.967%. The population attributable risk was 35.448 per 100 000. The attributable rate in standardized vaccination cohorts born after 2002 was 2.336 per 100 000. Compared with the cohorts born before 1992, the RR was 24.347 (P=0.000 0), the attributable risk was 54.549 per 100 000, and the attributable risk ratio was 95.893%, the population attributable risk ratio was 95.300%, the population attributable risk was 47.371 per 100 000, comparing to the natural exposed population. Conclusions The effectiveness of hepatitis B immunization program had been remarkable in Fujian province since 1992. However, further studies on the persistency of hepatitis B vaccine immunization and its public health significance still needed to be carried out. Key words: Hepatitis B; Cohort study; Incidence density