ABSTRACT
ObjectiveTo investigate the immunity and seroprevalence of hepatitis A and to identify the risk factors of hepatitis A infection in 0-18 year-old children and adolescents in Shanghai.MethodsSubjects were enrolled by stratifying and clustering random sampling method.Questionnaire interview was applied to investigate the socio-demographic and behavioral factors related to hepatitis A virus (HAV),and information on HAV immunization was abstracted from the immunization registration book of each subject.The enzyme-linked immunosorbent assay (ELISA) was used to qualitatively detect HAV IgM and quantitatively measure total HAV antibody in all subjects.Risk factors associated with HAV among the subjects without HAV vaccination were analyzed.ResultsA total of 2431 subjects were enrolled in the present study with negative HAV IgM antibody and total HAV antibody in 1483 subjects were sero-positive with positivity rate of 61％.Total HAV antibody positivity rates were declined with age increasing and were significantly higher in subjects with HAV vaccination than those without HAV vaccination records.Salad food,eating together without food separation in school and endoscopy inspection were risk factors for HAV infection.ConclusionsHAV vaccination strategies remarkably improve the total HAV antibody seropositive rate in children and adolescents in Shanghai.The risk of HAV infection exists if HAV vaccination is not administrated comprehensively.Therefore,strengthening HAV vaccination and health education are important for children and adolescents to prevent and control of hepatitis A in Shanghai.