Dataset from Persistence Study of GSK Biologicals' Tdap Vaccine (776423), 1, 3, 5 and 9 Years Following Administration as a Single Dose in NCT00346073 Study and to Evaluate the Immunogenicity and Safety of Boostrix as a Second Dose of Tdap, When Administered at Year 9

The purpose of this study is to evaluate the persistence of antibodies against all the vaccine antigens 1, 3, 5 and 9 years after an initial vaccination with Tdap, and also to assess immunogenicity and safety of another dose of Boostrix, administered in this study. This protocol posting deals with objectives and outcome measures of the extension phase. The objectives and outcome measures of the primary phase are presented in a separate protocol posting (NCT number = NCT00346073).