2-year Follow-up After a Single Dose Acellular Pertussis Vaccination

In July 2015-November 2016, a phase II/III randomized, observer-blind,controlled study of two acellular Pertussis vaccines (aP standalone and TdaP combined vaccined) manufactured by BioNet-Asia Co., Ltd. (Bionet) and chemically-detoxified Adacel Tdap vaccine was conducted in Bangkok, Thailand in healthy subjects aged 12-17 years (Protocol No. TDA202; http://clinicaltrials.in.th; Study ID:TCTR20150703002). A total of 450 subjects were enrolled into the study at 2 study sites (Site No.1:Faculty of Medicine Siriraj Hospital; Site No.2:Vaccine Trial Centre (VTC), Faculty of Tropical Medicine, Mahidol University) with equal number of 225 subjects enrolled at each study site. During the study, the subjects had been randomized in a 1:1:1 ratio to received intramuscularly a booster dose (0.5 mL) of the study vaccines. In this current study, persistence of pertussis antibodies induced by a booster dose of recombinant acellular Pertussis based vaccines (Pertagen and Boostagen) manufactured by Bionet will be evaluated and compared to the conventional chemically-detoxified Tdap vaccine (Adacel) at 2 years after previously immunized in the TDA202 study.