Persistence of Antibodies in Children Primed with Two Different Hexavalent Diphtheria, Tetanus, Acellular Pertussis, Hepatitis B, Inactivated Poliovirus and Haemophilus influenzae Type b Vaccines and Evaluation of Booster Vaccination

This study assessed the persistence of antibodies following primary vaccination with two commercially available, hexavalent diphtheria, tetanus, acellular pertussis, hepatitis B, inactivated poliovirus and Haemophilus influenzae type b vaccines (Infanrix hexa™ and Hexavac™). The immunogenicity and reactogenicity of booster vaccination with Infanrix hexa™ were also evaluated. A total of 329 children primed at 2, 4, and 6 months with Infanrix hexa™ (n=166) or Hexavac™ (n=163) received booster vaccination with Infanrix hexa™ at 12-19 months of age. Antibody concentrations were measured immediately before and 1 month after booster vaccination. Pre-booster persistence of antibodies to HBs, PRP and poliovirus types was significantly higher in children primed with Infanrix hexa™ than with Hexavac™, both in terms of seroprotection rate and GMCs/GMTs (p < 0.05). Boosting with Infanrix hexa™ elicited strong immune responses to all antigens irrespective of the primary vaccine used, with post-booster seroprotection r...