Inclusion Criteria: -Aged 6 months to < 22 months on the day of inclusion (means the day of the 6-month birthday to the day before the 22-month birthday)

• Participants who are healthy as determined by medical evaluation including medical history
• Born at full term of pregnancy (≥ 37 weeks)

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, 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 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
• History of medically diagnosed 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 who is HIV infected
  • 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

• Participant's biological mother's previous receipt or planned administration of an investigational RSV vaccine during pregnancy and/or breastfeeding.
• Receipt or planned receipt of any of the following vaccines prior to enrollment or after the first study intervention administration:
  • Any other intranasal live attenuated vaccine within the 28 days prior to and after Dose 1 study administration
  • Unless given on the day of Dose 1 study administration, any other injectable live attenuated vaccines within the 28 days prior to and after. Concomitant receipt on the day of Dose 1 study administration is allowed.
• 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. Previous receipt of an RSV monoclonal antibody within 6 months prior to the first study vaccine administration.

• 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
• Participation at the time of study enrollment or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.