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

Inclusion Criteria: * Male or female toddlers ≥12 to ≤15 months of age at the time of consent. * Healthy toddlers determined by clinical assessment, including medical history and clinical judgment, to be eligible for the study. * Have received 3 infant doses of 20vPnC with the last dose administered \>56 days before enrollment into the study. Documented confirmation of receipt will be collected prior to randomization. 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 (other than 20vPnC) or planned receipt during study participation.