title: Placebo-controlled efficacy study of hepatitis A vaccine in Valdivia, Chile.
abstract: A placebo-controlled, double-blind study on the efficacy of a hepatitis A vaccine (SmithKline Beecham Biologicals) was started in a region of Chile in September 1990, using hepatitis B vaccine as control. A total of 260 healthy children, 6-15 years of age, negative for antibody to hepatitis A virus (anti-HAV), antibody to HAV immunoglobulin M (IgM), hepatitis B surface antigen, and antibody to hepatitis B surface and core antigens by ELISA tests within 7 days before vaccination, were randomly assigned to two study groups: 128 children received the vaccine with a yellow label (group 1), and 132 children the vaccine with an orange label (group 2) at months 0, 1 and 6. Blood for serology and transaminase determination was drawn at months 1, 2, 6, 7 and 12. Both vaccines were tolerated equally well and no serious side effects were seen. In group 1 (presumed hepatitis A vaccine group), anti-HAV was detected (20% inhibition was used as the cut-off level) in 122 of 128 children (95.5%) tested at month 1, in 126 of 127 (99.2%) at month 2, in 126 of 127 (99.2%) at month 6 and in 126 of 126 (100%) at month 7. One anti-HAV seroconversion seen at month 1 was associated with presence of anti-HAV IgM and therefore probably represents HAV infection. Geometric mean anti-HAV concentration of the other children was 128, 342, 214 and 2301 mIU/ml at months 1, 2, 6 and 7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institute of Microbiology, Universidad Austral de Chile, Valdivia.
authors.forename: S
authors.initials: S
authors.lastname: Riedemann
authors.forename: G
authors.initials: G
authors.lastname: Reinhardt
authors.forename: G G
authors.initials: GG
authors.lastname: Frösner
authors.forename: H
authors.initials: H
authors.lastname: Ibarra
authors.forename: L
authors.initials: L
authors.lastname: Moraleda
authors.forename: V
authors.initials: V
authors.lastname: Hering
authors.forename: F
authors.initials: F
authors.lastname: Siegel
authors.forename: C
authors.initials: C
authors.lastname: Toledo
authors.forename: J
authors.initials: J
authors.lastname: Leon
authors.forename: J L
authors.initials: JL
authors.lastname: Gonzalez
mesh_terms: D000293:Adolescent; D002648:Child; D002677:Chile; D004311:Double-Blind Method; D005260:Female; D006506:Hepatitis A / Q000517:prevention & control*; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies / Q000096:biosynthesis* / Q000097:blood; D006507:Hepatovirus / Q000276:immunology*; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; 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; D007075:Immunoglobulin M; D015164:Vaccines, Inactivated; D014761:Viral Hepatitis Vaccines