title: Safety and immunogenicity of a new formulation of an inactivated hepatitis A vaccine.
abstract: The safety and immunogenicity of a new formulation of the inactivated hepatitis A vaccine, Avaxim, was evaluated in 189 children, aged 18 months to 15 years in a monocentric, open trial. Two vaccinations were given six months apart. Enrollment was balanced within three age groups: 18 months to 3 years, 4-8 years and 9-15 years. Antibody titers were measured blindly by an independent laboratory using a modified radioimmunoassay. Two weeks after the first dose, seroconversion was achieved by 94.6, 94.3 and 96.4% of initially HAV-seronegative subjects (antibody titre <20 mIU/ml) in each age group (youngest to oldest, respectively), with corresponding geometric mean titre concentrations (GMC) of 72.2, 54.3 and 47.1 mIU/ml. Just before the booster dose, the seroconversion rate was 100% in all groups, and the corresponding GMC values were 163, 169 and 111 mIU/ml. All groups included, a 22.6-fold rise in GMC from prebooster levels was observed four weeks after the booster dose. An explanatory analysis suggested a tendency for higher antibody levels in younger children at all vaccination time points. Local reactions were noted in 18.2% of the vaccinees after the first dose and in 8.5% after the booster dose. The rates of systemic reactions were 23.8% after the first dose and 11.4% after the booster dose. Overall, this trial demonstrated the good safety and immunogenicity profile of this vaccine in children aged 18 months to 15 years of age.
authors.affiliation: Pediatric Infectious Disease Units, Soroka University Medical Centre and the Faculty of Health Sciences, Beer Sheva, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Dagan
authors.forename: D
authors.initials: D
authors.lastname: Greenberg
authors.forename: P
authors.initials: P
authors.lastname: Goldenbertg-Gehtman
authors.forename: E
authors.initials: E
authors.lastname: Vidor
authors.forename: P
authors.initials: P
authors.lastname: Briantais
authors.forename: V
authors.initials: V
authors.lastname: Pinsk
authors.forename: O
authors.initials: O
authors.lastname: Athias
authors.forename: R
authors.initials: R
authors.lastname: Dumas
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006508:Hepatitis Antibodies / Q000097:blood*; D006507:Hepatovirus / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D007223:Infant; D008297:Male; D011863:Radioimmunoassay; D016037:Single-Blind Method; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000008:administration & dosage / 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