title: Waning-off effect of serum hepatitis B surface antibody amongst Taiwanese university students: 18 years post-implementation of Taiwan's national hepatitis B vaccination programme.
abstract: Hepatitis B virus (HBV) infection and its sequelae remain a major health problem for Taiwan. The national hepatitis B (HB) vaccination programme was first launched in 1984 to combat the spread of this infection. This study examined the status of HBV infection amongst students at a Taiwanese university in 2005, 18 years after the implementation of a nation-wide mass HB vaccination programme. In 2005, 5875 new university entrants, who were born during the period 1 July 1976 to 30 June 1988, were subdivided into one of 12 one-year-interval birth-year cohorts. Each student was individually tested for serum hepatitis B surface antigen (HBsAg), Antibody to hepatitis B surface antigen (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc) status. We observed a declining trend of past exposure to HB infection from 48.7% (1976 birth-year cohort) to 5.2% (1987 birth-year cohort). The prevalence of chronic HB infection also declined from 14.5% (1976 birth-year cohort) to 1.9% (1987 birth-year cohort). The prevalence of persistent HB immunity through (earlier) active vaccination declined from 72% (1984 birth-year cohort) to 41.6% (1987 birth-year cohort). The prevalence of HB infection-naïve individuals increased from 18.2% (1984 birth-year cohort) to 53.1% (1987 birth-year cohort). This study demonstrates that as the implementation of the mass HB vaccination programme in 1984, the incidence of HB infection in Taiwan has declined, although a 'waning-off' effect of serum anti-HBs to low or undetectable levels, which may not provide protection, amongst this student population has arisen, 18 years following the implementation of the nation-wide HB vaccination programme. Such a situation may mean that these individuals may not be effectively protected against future HB infection. A booster dose of HB vaccine, given 18 years following HB vaccination, perhaps even earlier, should be considered.
authors: Department of Family Medicine, Far Eastern Memorial Hospital, Pan Chiao, Taipei Hsien, Taiwan.
authors: F-H
authors: FH
authors: Su
authors: J-D
authors: JD
authors: Chen
authors: S-H
authors: SH
authors: Cheng
authors: K-Y
authors: KY
authors: Sung
authors: J-J
authors: JJ
authors: Jeng
authors: F-Y
authors: FY
authors: Chu
mesh_terms: D000328:Adult; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006078:Government Programs; D006509:Hepatitis B / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood* / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D008297:Male; D032541:Mass Vaccination; D016036:Seroepidemiologic Studies; D013334:Students; D013624:Taiwan / Q000453:epidemiology; D014495:Universities
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines