University of Texas Medical Branch

• Aged 6 months + 2 weeks for Cohort 1 and 12 months ± 2 weeks for Cohort 2 on the day of inclusion (means the day of the 6-month birthday + 2 weeks and "12 months ± 2 weeks" means the day of the 12-month birthday ± 2 weeks) - Participants who are healthy as determined by medical evaluation including medical history and physical examination - Born at full term of pregnancy (≥ 37 weeks) - For Cohort 1 (US/Puerto Rico participants only): Infant received the first dose of a hepatitis B vaccine at birth; first and second doses of routine vaccines containing diphtheria, tetanus, pertussis, Haemophilus influenzae type B (Hib), and inactivated poliovirus vaccine (IPV) antigens with either Vaxelis or Pentacel vaccine; and second or third doses of hepatitis B with either Vaxelis or RECOMBIVAX HB or other monovalent hepatitis B vaccine. The last dose of Vaxelis or Pentacel/RECOMBIVAX HB or alternate monovalent hepatitis B vaccine must be at least 28 days before the first study visit - For Cohort 1 (US/Puerto Rico participants only): Infant received the first and second doses of RotaTeq vaccine at least 28 days before the first study visit - For Cohort 1(US/Puerto Rico participants only): Infant received the first and second doses of an ACIP recommended pneumococcal conjugate vaccine at least 28 days before the first study visit - For Cohort 2 (US/Puerto Rico participants only): Infant received the first 3 doses of an Advisory Committee on Immunization Practice (ACIP) recommended pneumococcal conjugate vaccine at least 28 days before the first study visit

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, within the preceding 6 months; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months) - Known previous infection with diphtheria, tetanus, Hib, measles, mumps, rubella, rotavirus, pneumococcus, polio, hepatitis B virus - History of RSV infection, confirmed either clinically, serologically, or microbiologically - Known systemic hypersensitivity to any of the study intervention components, or history of a life-threatening reaction to the study intervention used in the study or to a product containing any of the same substances - Chronic illness that, in the opinion of the investigator, is at a stage where it might interfere with study conduct or completion. Chronic illness may include, but is not limited to, cardiac disorders, lung disease (including any history of reactive airway disease, receipt of bronchodilator or inhaled steroid therapy), atopy, renal disorders, auto-immune disorders, diabetes, psychomotor diseases, and known congenital or genetic diseases - History of medically diagnosed wheezing. Children with a history of recurrent wheezing will be excluded. Children with a previous single episode of wheezing may be included if that episode of wheezing was not associated with hospitalization or if the child does not have a family history of wheezing - Any acute febrile illness in the past 48 hours that according to investigator judgment is significant enough to interfere with successful inoculation on the day of vaccination. A prospective participant should not be included in the study until the condition has resolved or the febrile event has subsided - Probable or confirmed ongoing case of viral respiratory infection (including COVID 19, influenza, rhinovirus, etc.) at the time of enrollment. A prospective participant should not be included in the study until the respiratory infection has resolved. - Member of a household that contains an immunocompromised individual, including, but not limited to: - A person living with human immunodeficiency virus (HIV) A person who has received chemotherapy within the 12 months prior to study enrollment A person who has received (within the past 6 months) or is receiving (at the time of enrollment) immunosuppressant agents A person living with a solid organ or bone marrow transplant Potential close contact with other immunocompromised individual within 30 days after each vaccination as per investigator's discretion - History of definitive contraindications to any of the concomitant vaccines that will be administered as part of the study protocol - Participant's biological mother with previous receipt or planned administration of an investigational or licensed RSV vaccine during pregnancy and/or breastfeeding - Receipt of any vaccine in the 4 weeks preceding the first study intervention administration or planned receipt of any vaccine outside of study protocol in the 4 weeks following any study intervention administration, except for influenza and/or COVID-19 vaccination, which may be received at least 1 week before or 1 week after any study vaccination. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines, as applicable per local recommendations. - Previous receipt of a licensed or investigational RSV vaccine or receiving any anti RSV product (such as ribavirin or RSV immune globulin or RSV monoclonal antibody) at the time of enrollment - Receipt of immune globulins, blood or blood-derived products in the past 3 months - Receipt of intranasal and intra-ocular medications within 3 days prior to study enrollment - Receipt of Beyfortus or other RSV antibodies Note: The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.