Dose-Ranging Study to Evaluate a 25-Valent Pneumococcal Conjugate Vaccine

Inclusion Criteria: * Healthy adults who are 18 through 49 years old on the day of randomization (Day 1). * Participant must provide voluntary written informed consent to participate in the study. * Participant must be able to comprehend and comply with study requirements and procedures and be willing and able to return for all scheduled follow-up visits. * Adult female participants who are not surgically sterile must have a negative pregnancy test at screening and negative pregnancy test prior to vaccination and must agree to employ a highly effective method to avoid pregnancy through Day 57 of the study. Exclusion Criteria: * Use of any investigational medicinal product within 90 days prior to randomization or planned use of such a product during the period of study participation. * Adults who have previously been vaccinated against S. pneumoniae. * History of microbiologically confirmed invasive disease caused by S. pneumoniae. * History of allergic disease (including angioedema) or history of a serious reaction to any prior vaccination or known hypersensitivity to any component of the study vaccines, including PEG. * Any abnormal vital sign deemed clinically relevant by the PI. * Acute illness at time of randomization (moderate or severe) and/or fever (body temperature of ≥ 38.0°C) * History of any non-study vaccine administration within 14 days of study vaccine administration. * No planned vaccines until after Day 29 (Visit 3). * Chronic administration (defined as mor…