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 andclinical judgment, to be eligible for the study.

• Have received 3 infant doses of 20vPnC at 2, 4, and 6 months of age, with the lastdose administered >56 days before enrollment into the study. Documented confirmationof receipt will be collected prior to randomization.

Exclusion Criteria:

• History of severe adverse reaction associated with a vaccine and/or severe allergicreaction (eg, anaphylaxis).

• Major known congenital malformation or serious chronic disorder.

• Other acute or chronic medical or psychiatric condition or laboratory abnormalitythat may increase the risk associated with study participation or investigationalproduct administration or may interfere with the interpretation of study resultsand, in the judgment of the investigator, would make the participant inappropriatefor entry into this study.

• Previous vaccination with any licensed or investigational pneumococcal vaccine (other than 20vPnC) or planned receipt during study participation.