title: Seroprevalence of Hepatitis-B infection amongst Taiwanese university students 18 years following the commencement of a national Hepatitis-B vaccination program.
abstract: In Taiwan, the nation-wide Hepatitis-B virus (HB) vaccination program was first launched in July 1984 and was directed to those infants born to hepatitis B surface antigen (HBsAg) carrier mothers in Taiwan. From July 1986 onwards, all infants born in Taiwan were immunized against HB. This study examined the HB-infection status amongst students at a Taiwanese university 18 years subsequent to the implementation of universal HB vaccination. A total of 1,969 new university entrants in 2005 were grouped into 1 of 3 distinct birth cohorts according to their HB-vaccination schedule (cohort-1 students born prior to July 1, 1984; cohort-3 students born subsequent to June 30, 1986) and were examined for their serum HBsAg, antibody to hepatitis B surface antigen (anti-HBs), and antibody to hepatitis B core antigen (anti-HBc) status. Immunity arising from vaccination was defined as an anti-HBs level 10 mIU/ml. We observed a trend toward a decreasing anti-HBc-positive rate and a decreasing HBsAg carrier rate from, respectively, 26.5 and 8.7% for cohort-1 to 4.7 and 1.7% for cohort-3 students. The prevalence of students featuring seronegativity for all three HB markers increased from 12.3% for cohort-1 to 48.8% for cohort-3 individuals. Amongst the 1,695 subjects revealing seronegativity for HBsAg and anti-HBc, their anti-HBs level was analyzed according to their birth year. The prevalence of students featuring a non-protective anti-HBs level increased from 11.9% for birth-year 1984 individuals to 48.2% for birth-year 1987 students. The introduction of HB vaccine has effectively reduced the transmission of HBV infection in Taiwan, 18 years subsequent to the commencement of the universal HB-vaccination program. A "waning-off" effect of anti-HBs seropositivity acquired from the HB vaccination program has also been observed.
authors.affiliation: Department of Family Medicine, Far Eastern Memorial Hospital, Pan Chiao, Taipei County, Taiwan.
authors.forename: Fu-Hsiung
authors.initials: FH
authors.lastname: Su
authors.forename: Jong-Dar
authors.initials: JD
authors.lastname: Chen
authors.forename: Shu-Hsing
authors.initials: SH
authors.lastname: Cheng
authors.forename: Ching-Hung
authors.initials: CH
authors.lastname: Lin
authors.forename: Yi-Hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Fang-Yeh
authors.initials: FY
authors.lastname: Chu
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006078:Government Programs; D006509:Hepatitis B / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D008297:Male; D016036:Seroepidemiologic Studies; D013334:Students; D013624:Taiwan / Q000453:epidemiology; D014495:Universities; D014611:Vaccination
chemical_list: D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines