Safety and immunogenicity of a combined Tetanus, Diphtheria, recombinant acellular Pertussis vaccine (TdaP) in healthy Thai adults

ABSTRACTBackground: An acellular Pertussis (aP) vaccine containing recombinant genetically detoxified Pertussis Toxin (PTgen), Filamentous Hemagglutinin (FHA) and Pertactin (PRN) has been developed by BioNet-Asia (BioNet). We present here the results of the first clinical study of this recombinant aP vaccine formulated alone or in combination with tetanus and diphtheria toxoids (TdaP). Methods: A phase I/II, observer-blind, randomized controlled trial was conducted at Mahidol University in Bangkok, Thailand in healthy adult volunteers aged 18–35 y. The eligible volunteers were randomized to receive one dose of either BioNet's aP or Tetanus toxoid-reduced Diphtheria toxoid-acellular Pertussis (TdaP) vaccine, or the Tdap Adacel® vaccine in a 1:1:1 ratio. Safety follow-up was performed for one month. Immunogenicity was assessed at baseline, at 7 and 28 d after vaccination. Anti-PT, anti-FHA, anti-PRN, anti-tetanus and anti-diphtheria IgG antibodies were assessed by ELISA. Anti-PT neutralizing antibodies were...