The clinical trial is a phase III, double-blind, randomised, controlled, multi-centre, clinical trial, on the immunogenicity and safety of TdaP vaccine in comparison to Td vaccine when given as a booster vaccination to adults who were vaccinated with D, T and wP vaccine according to the Danish vaccination programme in their childhood.

Healthy, adult, female or male volunteers, who completed primary vaccination with diphtheria (D), tetanus (T) and whole cell pertussis vaccine (wP), typically during their childhood, is the target population.

Inclusion Criteria:

1. Healthy female or male adult of ≥ 18 years of age
2. Completed primary vaccination with diphtheria (D), Tetanus (T) and whole cell pertussis (wP) vaccines in Denmark
3. Signed informed consent
4. Prepared to grant authorised persons access to medical records
5. Likely to comply with instructions

Exclusion Criteria:

1. Congenital or acquired immunodeficiency or progressive neurologic disease
2. Uncontrolled epilepsy or progressive encephalopathy
3. Previous experience of serious adverse reaction(s) after vaccinations with diphtheria-, tetanus- acellular or whole cell pertussis- vaccines
4. Vaccinated with any diphtheria, tetanus or pertussis toxoid containing vaccine within 5 years before inclusion
5. Vaccinated with any tetanus toxoid, diphtheria toxoid or diphtheria CRM197 protein conjugated vaccine within 5 years before inclusion
6. Known tetanus-, diphtheria- or pertussis disease/infection within 5 years before inclusion
7. Known hypersensitivity or history of allergic reactions to any of the active or inactive constituents of the TdaP or Td vaccines
8. Vaccinated with a live or inactivated vaccine within 1 month before inclusion
9. Administration of immune modulating drugs (such as immunoglobulin, systemic corticosteroids, blood products, azathioprine, cyclosporine, infliximab) within 3 months before inclusion
10. Administration of any investigational drug product or vaccine within 1 month before inclusion
11. Females if pregnant or breastfeeding or not willing to use contraception during the trial