Long-term antibody persistence induced by a combined hepatitis A and B vaccine in children and adolescents

SummaryTwo cohorts, comprising of subjects aged 1–6 years and 6–15 years were vaccinated with Twinrix™ according to a 0-, 1- and 6-month schedule. The 1–6 years cohort was followed up for 7.5 years and the 6–15 years cohort for 10 years.At the latest follow-up time point, all subjects were seropositive for anti-HAV antibodies, while 86.5% (32/37) and 95.5% (21/22) had anti-HBs ≥ 10 mIU/ml in the 1–6 years and in the 6–15 years cohort. The geometric mean concentrations (GMCs; mIU/ml) were 233 and 680 for anti-HAV antibodies, and 147 and 165 for anti-HBs antibodies, in the 1–6 years and 6–15 years cohorts, respectively. The high persistence of circulating anti-HAV and anti-HBs antibodies in children and adolescents demonstrates the long-term protection offered by Twinrix™ in these age groups.