Study of Mixed Vaccination Schedules With a 21-valent Pneumococcal Conjugate Vaccine and a 20-valent Pneumococcal Conjugate Vaccine in Healthy Infants From Approximately 2 Months of Age

Inclusion Criteria: * Aged 42 to 89 days on the day of inclusion * Participants who are healthy as determined by medical evaluation including medical history and physical examination * Born at full term of pregnancy (≥ 37 weeks) and with a birth weight ≥ 2.5 kg or born after a gestation period above 28 (\> 28 weeks) through 36 weeks with a birth weight ≥ 1.5 kg, and in both cases medically stable as assessed by the investigator Exclusion Criteria: Participants are excluded from the study if any of the following criteria apply: * Known or suspected congenital or acquired immunodeficiency; or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy * History of microbiologically confirmed Streptococcus pneumoniae infection or disease. * History of seizure or significant stable or progressive neurologic disorders such as inflammatory nervous system diseases, encephalopathy, cerebral palsy * Known systemic hypersensitivity to any of the study interventions components, or history of a life-threatening reaction to the study interventions used in the study or to a product containing any of the same substances * Thrombocytopenia, or known thrombocytopenia, as reported by the parent/legal acceptable representative (LAR), contraindicating intramuscular (IM) injection. * Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating IM injection * Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion * Moderate or severe acute illness/infection (according to investigator judgment) or febrile illness (temperature ≥ 38.0°C \[≥ 100.4°F\]) on the day of study intervention administration. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided. * Previous vaccination against Streptococcus pneumoniae * Receipt of immune globulins, blood or blood-derived products since birth * Participation at the time of study enrollment (or in the 6 weeks preceding the first study intervention administration) or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.