This study evaluates the safety and immunogenicity of a higher dose formulation of a new live attenuated vaccine, BPZE1, intended to prevent Bordetella pertussis nasopharyngeal colonization and pertussis disease, and investigates whether higher doses of BPZE1 induce the live vaccine to colonize subjects' nasopharynx. The study is a Phase Ib (high dose), single centre, dose-escalating, placebo-controlled study of the live attenuated B. pertussis strain BPZE1 given as a single intranasal dose to healthy adult volunteer.

Inclusion Criteria:

1. Healthy individual between 18 and 32 years of age, vaccinated or unvaccinated with acellular pertussis vaccine.
2. Female subject of child bearing potential must be willing to ensure that they use a highly efficient method of contraception during the study (e.g. contraceptive pill, intrauterine contraceptive device).
3. Informed consent form (ICF) signed by the subject.
4. Subject shall be able to attend all scheduled visits and to understand and comply with the study procedures.

Exclusion Criteria:

1. Individual with PT and/or PRN serum IgG antibodies ≥20 International units/ml (IU/ml). NOTE! One control group with PRN serum IgG antibodies ≥ 20 IU/ml will be included.
2. Vaccinated with the study vaccine in the Child Innovac study (EudraCT number 2010-019936-11).
3. Pregnant or lactating women. Pregnancy not planned and to be avoided during the study by use of effective contraceptive methods.
4. Blood pressure after resting ≥ 150/90 mm Hg at screening.
5. Heart rate after resting ≥ 80 bpm at screening.
6. Respiratory rate after resting ≥ 20/minute at screening.
7. Unwillingness to refrain from the use of nicotine products from screening through day 28.
8. Use of narcotic drugs and/or a history of drug/alcohol abuse with in the past 2 years prior to screening
9. The subject has donated blood or suffered from blood loss of at least 450 ml (1 unit of blood) within 60 days prior to screening or donated plasma within 14 days prior to screening.
10. Receipt of immunoglobulin, blood derived products, systemic corticosteroids or other immunosuppressant drugs within 90 days prior to day 0.
11. Asthma or other chronic respiratory problems.
12. Use of corticosteroids in the respiratory tract (e.g. nasal steroids, inhaled steroids) with in 30 days prior to day 0.
13. Receipt of a vaccine within the last 30 days prior to day 0 or planned vaccination with in the next 30 days after day 0.
14. Known hypersensitivity to any component of the study vaccine.
15. Current participation in any other clinical trial or participation (and during the whole study) in any clinical trial in the previous 3 months prior to day 0.
16. Inability to adhere to the protocol, including plans to move from the area.
17. Family (first degree) history of congenital or hereditary immunodeficiency.
18. Past or present infection with HIV, hepatitis B or C.
19. Chronic conditions requiring ongoing active medical interventions, such as diabetes mellitus or cardiovascular disease.
20. Any autoimmune or immunodeficiency disease/condition (inherited or iatrogenic).
21. Any medical condition which, in the opinion of the investigator, might interfere with the evaluation of the study objectives or might affect the safety of the individual, e.g. evolving encephalopathy not attributable to another identifiable cause within 7 days of administration of a previous dose of any vaccine, hospitalization due to major depression or history of suicidal attempt.
22. Abnormal laboratory values outside the limit of normal values for the screening laboratory with clinical significance at the discretion of the investigator.
23. Person in frequent contact with children less than 1 year of age (parent, childcare worker, nurse, etc) or residence in the same household as persons with known immunodeficiency including persons on immunosuppressant therapy.

14 days, 1 month, 3 months, 6 months, 1 year