Trial to Evaluate the Safety and Immunogenicity of a 20-Valent Pneumococcal Vaccine in Adults 65 Years of Age or Older With Prior Pneumococcal Vaccination

Inclusion Criteria

1. Male or female adults 65 years of age or greater.

2. Adults determined by clinical assessment, including medical history and clinical
judgment, to be eligible for the study, including adults with preexisting stable
disease, defined as disease not requiring significant change in therapy in the
previous 6 weeks or hospitalization for worsening disease within 12 weeks before
receipt of investigational product.

3. Female subject of nonchildbearing potential; male subject not able to father children
or who is able to father children and willing to use a highly effective method of
contraception.

4. Male or female adults who meet 1 of the following:

1. Vaccination with PPSV23 greater than or equal to 1 year and less than or equal to
5 years prior to vaccination in the study, and no prior 13vPnC vaccination
(Cohort A).

2. Vaccination with 13vPnC greater than or equal to 6 months prior to vaccination in
the study, and no prior PPSV23 vaccination (Cohort B).

3. Vaccination with 13vPnC followed by PPSV23 (PPSV23 vaccination greater than or
equal to 1 year prior to vaccination in the study) (Cohort C).

Exclusion Criteria

1. Serious chronic disorder including metastatic malignancy, severe chronic obstructive
pulmonary disease (COPD) requiring supplemental oxygen, end-stage renal disease with
or without dialysis, clinically unstable cardiac disease, or any other disorder that,
in the investigator's opinion, excludes the subject from participating in the study.

2. History of microbiologically proven invasive disease caused by S pneumoniae.