A Study to Learn About How a New Pneumococcal Vaccine Works in Infants.

Inclusion Criteria: * infants who are 2 months of age in Group 1. * infants who are 2 to 6 months of age in Groups 2 and 3. * Healthy infants determined by clinical assessment, including medical history and clinical judgment, to be eligible for the study. Exclusion Criteria: * History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis). * Major known congenital malformation or serious chronic disorder. * Other acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the participant inappropriate for entry into this study. * Previous vaccination with any licensed or investigational pneumococcal vaccine, or planned receipt through study participation.