Group 1: Boostrix + Menactra on Day 0, blood samples at Month 0 and Month 1 Group 2: Boostrix on Day 0, Menactra at Month 1, blood samples at Month 0, Month 1, and Month 2 Group 3: Menactra on Day 0, Boostrix at Month 1, blood samples at Month 0, Month 1 and Month 2 Treatment allocation: randomized 1:1:1 Type of study: self-contained Duration of the study: Approximately one month for each subject in Group 1 and approximately two months for each subject in the Group 2 and Group 3."