This study is the first study of Sanofi's Pentavalent Meningococcal ABCYW vaccine clinical development program to be conducted in the pediatric population below 10 years of age. The aim of the study is to assess 2 formulations of the MenPenta vaccine compared to licensed meningococcal vaccines when administered alone in children (Stage 1) or concomitantly with routine pediatric vaccines in toddlers (Stage 2) and infants (Stage 3).

Study details include:

The study duration per participant will be up to 12 months for children in Stage 1 and toddlers in Stage 2 and 16 to-19 months for infants in Stage 3.

Inclusion Criteria:

• Aged 2 to 9 years (Stage 1) or 12 to 15 months (Stage 2) or 56 to 89 days (Stage 3) on the day of inclusion
• For infants and toddlers, born at full term of pregnancy (≥37 weeks) and with a birth weight ≥ 2.5 Kg or born after a gestation period of 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, based on the following definition: "Medically stable" refers to the condition of premature infants who do not require significant medical support or ongoing management for debilitating disease and who have demonstrated a clinical course of sustained recovery by the time they receive the first dose of study intervention
• Participants who are overtly healthy as determined by medical evaluation including medical history, physical examination, and judgement of 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, within the preceding 6 months or since birth for infants; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks within the past 3 months or since birth for and infants)
• History of any meningitis infection, confirmed either clinically, serologically, or microbiologically
• At high risk of meningococcal infection during the study
• Known systemic hypersensitivity to any of the study intervention 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
• Individual with active tuberculosis
• History of Guillain-Barré syndrome
• For Stage 3 infants: History of intussusception
• Previous vaccination against meningococcal serogroups A, B, C, W, and/or Y with an investigational or marketed vaccine
• For Stage 3 infants: receipt of the first dose of rotavirus vaccine less than 28 days before the first trial vaccination

NOTE: The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Partially blinded (treatment assignment is blinded between the two investigational formulation groups, and open label between the investigation and the comparator group)

• Laboratory personnel will be blinded to the treatment assignment
• Participants, Investigators, and Site staff preparing and administering the study intervention will be unblinded between the MenPenta and comparator groups but will be blinded between the 2 MenPenta groups The Sponsor will be partially blinded. At the time of periodic data reviews, additional measures are put in place to maintain the blind of the study participants for the Sponsor staff. The data review will be conducted on the basis of blinded outputs (where data of the 2 MenPenta groups and the control group will be reviewed in aggregate, without any distinction by group). By design, the Sponsor team will have access to partially blinded data for individual participants (eg, for assessment of SAE)