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Hum Vaccin Immunother. 2012 Jul;8(7):921-8. doi: 10.4161/hv.20248. Epub 2012 Jul 1.

Homologous and heterologous antibody responses to a one-year booster dose of an MF59(®) adjuvanted A/H5N1 pre-pandemic influenza vaccine in pediatric subjects.

Author information

1
University of Tampere Medical School, Tampere, Finland. timo.vesikari@uta.fi

Abstract

BACKGROUND:

Primary immunization with two doses of MF59 (®) -adjuvanted A/H5N1 influenza vaccine has been shown to be highly immunogenic and well tolerated in children and adolescents. Assessment of long-term antibody persistence after priming, and the effects of a one-year booster dose in children and adolescents was needed.

OBJECTIVES:

This study assessed homologous and heterologous antibody responses to a one-year booster dose of MF59-adjuvanted A/H5N1 influenza vaccine in previously primed children.

RESULTS:

Twelve months after primary vaccination, persistent, homologous, seroprotective HI antibody titers (≥ 40) were observed in 46%, 26% and 30% of toddlers, children and adolescents; following booster vaccination, seroprotection rates increased to 99%, 98% and 91%, respectively. All toddlers and children, and 99% of adolescents achieved MN antibody titers ≥ 40. Cross-reactive A/H5N1 antibodies were detected in 94-98% of subjects after booster vaccination.

SUBJECTS AND METHODS:

Twelve months after primary vaccination, toddlers, children and adolescents received a single booster dose of the same A/H5N1 vaccine. Paired sera were collected before and three weeks after booster vaccination. Homologous antibody responses against the A/Vietnam/1194/2004 vaccine strain were measured by hemagglutination inhibition (HI), single radial hemolysis (SRH) and microneutralization (MN) assays. Heterologous antibody responses against A/Indonesia/5/2005 and A/Anhui/1/2005 strains were assessed by MN assay only.

CONCLUSIONS:

Two priming doses of MF59-adjuvanted A/H5N1 vaccine resulted in homologous and heterologous antibody responses which persisted for up to one year after immunization. A one-year booster dose was highly immunogenic, generating high homologous and cross-reactive A/H5N1 antibody titers.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT00537524.

PMID:
22777094
DOI:
10.4161/hv.20248
[Indexed for MEDLINE]

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