The vaccines in the study are COVAXIS (Td5ap), Sanofi Pasteur Canada, and diTekiBooster (Td1aP), Statens Serum Institut, Denmark.~The primary objective of the study is to describe the immune response to diphtheria toxin, tetanus toxoid, pertussis toxin, filamentous haemagglutinin (FHA), fimbriae 2/3 and pertactin four weeks after immunization with Td1aP and Td5ap.~The secondary objectives include:~describing the safety of a fith dose of DTP vaccines in 14-15 year-old children by observing systemic and local adverse reactions~describing pre-booster antibody levels~describing pre-booster and post-booster IgG and IgA levels in saliva~describing in a subpopulation the pre-booster and post-booster T cell immune responses as determined by the production of cytokines~describing in a subpopulation the pre-booster and post-booster B cell immune responses as determined by the number of effector and memory B-cells~The sample size is 400 subjects (200 in group 1 and 200 in group 2). It will be an open-label, randomized, multi-centre study in which group 1 will receive Td5ap as a single injection and group 2 will receive Td1aP as a single injection. DTP antibodies will be measured before and 28 days (+ 14 days) after Td5ap and Td1aP vaccination. The proportion of children with positive IgG antibody response will be measured in each study arm. Sera will be tested blindly by established ELISA methods and saliva samples will be analyzed by exploratory assays. In a subpopulation cellmediated immunity will be analyzed. The safety evaluation criteria will be the percentage of subjects with adverse events describing injection-site adverse reactions, systemic adverse events, daily temperatures and serious adverse events.
Open-label, randomized, multi-centre study in which 400 subjects, divided into two groups, will receive Td5ap or Td1aP as a single injection. We will then describe the immune response and safety profile of the combined vaccine booster.