title: Immunogenicity and safety of an inactivated hepatitis A vaccine amongst Singaporeans.
abstract: The immunogenicity and reactogenicity of an inactivated hepatitis A virus (HAV) vaccine was studied in healthy Singaporean adult volunteers. One hundred and forty healthy volunteers with normal alanine (ALT) and aspartate (AST) transaminases and no previous exposure to HAV, received three 1 ml doses (720 ELISA units) of an inactivated HAV vaccine (Smithkline Beechams Biologicals) following a 0, 1, 6 months vaccination schedule. All subjects were asked to record and grade the severity of any reactions for three consecutive days after each dose. Serum ALT and AST as well as anti-HAV were measured at 0, 1, 2, 6 and 7 months after the first vaccine dose. Anti-HAV seroconversion occurred when levels rose above 40 mIU/ml. Eighty-five percent of vaccinees seroconverted after the first innoculation and 99% after the second injection. All vaccinees seroconverted after the third dose. Geometric mean anti-HAV titers (GMTs) were, respectively, 119, 391, 4406 mIU/ml one month after each of the three doses. The most common side effect was transient pain and tenderness at the vaccination site. No elevation of ALT or AST levels were noted during the study period. The inactivated hepatitis A vaccine used in this study is safe and highly immunogenic in the local adult population. Two doses one month apart appeared to give adequate protection.
authors.affiliation: Department of Medicine, National University Hospital, Singapore.
authors.forename: R
authors.initials: R
authors.lastname: Guan
authors.forename: H S
authors.initials: HS
authors.lastname: Ng
authors.forename: K M
authors.initials: KM
authors.lastname: Fock
authors.forename: K Y
authors.initials: KY
authors.lastname: Ho
authors.forename: I
authors.initials: I
authors.lastname: Yap
authors.forename: J Y
authors.initials: JY
authors.lastname: Kang
authors.forename: W C
authors.initials: WC
authors.lastname: Chow
authors.forename: C N
authors.initials: CN
authors.lastname: Chew
authors.forename: C
authors.initials: C
authors.lastname: Ng
authors.forename: C J
authors.initials: CJ
authors.lastname: Teo
mesh_terms: D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D016009:Chi-Square Distribution; D005260:Female; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies / Q000097:blood; D006801:Humans; D007115:Immunization Schedule; D008297:Male; D012846:Singapore; D015164:Vaccines, Inactivated / Q000009:adverse effects / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000009:adverse effects / Q000276:immunology
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies; D015164:Vaccines, Inactivated; D014761:Viral Hepatitis Vaccines; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase