Co-administration Study of an Investigational Live-Attenuated Respiratory Syncytial Virus Vaccine in Infants and Toddlers

Inclusion Criteria:

• Aged 6 months for Cohort 1 and 12 months for Cohort 2 on the day of inclusion ("6months" means from the day of the 6-month birthday to the day before the 7-monthbirthday and "12 months" means from the day of the 12-month birthday to the daybefore the 13-month birthday)

• Participants who are healthy as determined by medical evaluation including medicalhistory and physical examination

• For Cohort 1: Infant received doses of vaccines containing hepatitis B, diphtheria,tetanus, pertussis, Haemophilus influenzae type B (Hib), and inactivated poliovirusvaccine (IPV) antigens, with Advisory Committee on Immunization Practice (ACIP)recommended vaccines. The last dose(s) of these vaccines must be at least 28 daysbefore the first study visit

• Infant received the recommended doses of a recommended pneumococcal conjugatevaccine (as per local schedule) at least 28 days before the first study visit.

Exclusion Criteria:

• Known or suspected congenital or acquired immunodeficiency; or receipt ofimmunosuppressive 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 3months)

• Known previous infection with diphtheria, tetanus, Hib, measles, mumps, rubella,rotavirus, pneumococcus, polio, hepatitis B virus

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

• Chronic illness that, in the opinion of the investigator, is at a stage where itmight interfere with study conduct or completion

• History of medically diagnosed wheezing

• Any acute febrile illness in the past 48 hours that according to investigatorjudgment is significant enough to interfere with successful inoculation on the dayof vaccination. A prospective participant should not be included in the study untilthe 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 prospectiveparticipant should not be included in the study until the respiratory infection hasresolved.

• Member of a household that contains an immunocompromised individual, including, butnot limited to:

• A person living with human immunodeficiency virus (HIV)

• A person who has received chemotherapy within the 12 months prior to studyenrollment

• A person who has received (within the past 6 months) or is receiving (at the time ofenrollment) immunosuppressant agents

• A person living with a solid organ or bone marrow transplant

• Potential close contact with other immunocompromised individual within 30 days aftereach vaccination as per investigator's discretion

• History of definitive contraindications to any of the concomitant vaccines that willbe administered as part of the study protocol

• Participant's biological mother with previous receipt or planned administration ofan investigational RSV vaccine during pregnancy and/or breastfeeding

• Receipt of any vaccine in the 4 weeks preceding RSVt vaccine administration orplanned receipt of any vaccine outside of study protocol in the 4 weeks followingRSVt vaccine administration, except for influenza and/or COVID-19 vaccination, whichmay be received at least 1 week before or 1 week after RSVt vaccine administration

• Previous receipt of an investigational RSV vaccine or receiving any anti RSV product (such as ribavirin or RSV immune globulin) 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 studyenrollment

• Previous receipt of an RSV monoclonal antibody within 6 months prior to the firststudy vaccine administration or planned receipt for duration of the study

• For Cohort 1: Prior receipt of routine 6-month pediatric vaccine doses (as per localschedule)

• For Cohort 2: Prior receipt of routine 12-month pediatric vaccine doses (as perlocal schedule)

• 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.