Study of Two Investigational Pneumococcal Vaccines in Healthy Adults

This study is designed to evaluate the safety, tolerability, and immunogenicity of two investigational pneumococcal vaccines at three dose levels in healthy adults.

Primary Objective:

- To evaluate the safety and tolerability of two investigational pneumococcal vaccines.

Observational Objective:

- To evaluate the immunogenicity of the investigational pneumococcal vaccines.

An initial cohort of 6 participants will receive a single dose of one of two investigational pneumococcal vaccines. After safety evaluation of that cohort, additional cohorts will receive 2 injections 30 days apart of same investigational pneumococcal vaccine at same or increased dose level. All participants will be monitored for safety for 30 days after each vaccination.

Eligibility Criteria:
Inclusion Criteria:

* Aged 18 to 50 years on the day of inclusion
* Informed consent form has been signed and dated
* Able to attend all scheduled visits and comply with all trial procedures
* Subject is healthy, as determined by medical history and physical examination
* For a woman of child-bearing potential, use of an effective method of contraception or abstinence from at least 4 weeks prior to first vaccination until 4 weeks after the last vaccination.

Exclusion Criteria:

* Known pregnancy or positive serum/urine pregnancy test
* Currently breastfeeding a child
* Chronic illness, that in the opinion of the investigator, is at a stage that could interfere with trial conduct or completion
* Participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding the first trial vaccination
* Planned participation in another clinical trial during the present trial period
* Known or suspected congenital or acquired immunodeficiency, or receipt of immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months)
* Known systemic hypersensitivity to any of the vaccine components or history of a life threatening reaction to the trial vaccine(s) or to a vaccine containing any of the same substances
* Current alcohol abuse or drug addiction that may interfere with the subject's ability to comply with trial procedures
* Receipt of blood or blood-derived products in the past 3 months, that might interfere with the assessment of immune response
* Receipt of any vaccine in the 4 weeks preceding the first trial vaccination
* Planned receipt of any vaccine in the 4 weeks following the trial vaccination
* Known seropositivity for Human Immunodeficiency Virus (HIV), Hepatitis B or Hepatitis C
* Laboratory confirmed / self-reported thrombocytopenia contraindicating intramuscular vaccination
* Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily
* Identified as a study site employee who is involved in the protocol and may have direct access to trial-related data
* Previous vaccination against pneumococcal disease (in the previous 5 years)
* History of pneumococcal infection (confirmed either clinically, serologically, or microbiologically) within 5 years
* At high risk for pneumococcal infection during the trial
* Living in a household with children \< 5 years of age.