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 medicalhistory and physical examination

• Born at full term of pregnancy (≥ 37 weeks) and with a birth weight ≥ 2.5 kg or bornafter 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 ofimmunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; orlong-term systemic corticosteroid therapy

• History of microbiologically confirmed Streptococcus pneumoniae infection ordisease.

• History of seizure or significant stable or progressive neurologic disorders such asinflammatory nervous system diseases, encephalopathy, cerebral palsy

• Known systemic hypersensitivity to any of the study interventions components, orhistory of a life-threatening reaction to the study interventions used in the studyor to a product containing any of the same substances

• Thrombocytopenia, or known thrombocytopenia, as reported by the parent/legalacceptable 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 itmight interfere with study conduct or completion

• Moderate or severe acute illness/infection (according to investigator judgment) orfebrile illness (temperature ≥ 38.0°C [≥ 100.4°F]) on the day of study interventionadministration. A prospective participant should not be included in the study untilthe 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 firststudy intervention administration) or planned participation during the present studyperiod in another clinical study investigating a vaccine, drug, medical device, ormedical procedure

Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.