Primary Objective:

To demonstrate:

• the non-inferiority of the seroprotection rate (antibody titers greater than or equal to [>=] 1:8) to meningococcal serogroup C following the administration of MenACYW Conjugate or Nimenrix® as measured by serum bactericidal assay using human complement (hSBA). If this non-inferiority was demonstrated, then
• the non-inferiority of the antibody response (geometric mean titers [GMT]). If this non-inferiority was demonstrated, then
• the superiority of the antibody response (GMT). If this superiority was demonstrated, then
• the superiority of the seroprotection rate.

Or to demonstrate:

• the non-inferiority of the seroprotection rate (antibody titers >= 1:8) to meningococcal serogroup C following the administration of MenACYW Conjugate or NeisVac-C® as measured by serum bactericidal assay using baby rabbit complement (rSBA). If this non-inferiority was demonstrated, then
• the non-inferiority of the antibody response (GMT). If this non-inferiority was demonstrated, then
• the superiority of the antibody response (GMT).

Secondary Objective:

To demonstrate:

• the non-inferiority of the seroprotection rate (antibody titers >= 1:8) to meningococcal serogroup C following the administration of MenACYW Conjugate vaccine or Nimenrix® as measured by rSBA. If this non-inferiority was demonstrated, then
• the non-inferiority of the antibody response (GMT). If this non-inferiority was demonstrated, then
• the superiority of the antibody response (GMT).

Or to demonstrate:

• the non-inferiority of the seroprotection rate (antibody titers >= 1:8) to meningococcal serogroup C following the administration of MenACYW Conjugate vaccine or NeisVac-C® as measured by hSBA. If this non-inferiority was demonstrated, then
• the non-inferiority of the antibody response (GMT). If this non-inferiority was demonstrated, then
• the superiority of the antibody response (GMT) .

Study duration per participant was approximately 30 days including: 1 day of screening and vaccination, a phone call and a safety-follow up/end of study visit at Day 8 and Day 30 after vaccine administration, respectively.

Safety assessment included solicited reactions within 7 days after vaccination, unsolicited adverse events up to 30 days after vaccination, serious adverse events and adverse event of special interest throughout the study.

Inclusion criteria :

• Aged 12 to 23 months on the day of the first study visit ("12 to 23 months" means from the 12th month after birth to the day before the 24th month after birth).
• Informed consent form (ICF) had been signed and dated by the parent(s)/legally acceptable representative(s) and by an independent witness if required by local regulations.
• Participant and parent/legally acceptable representative were able to attend all scheduled visits and complied with all trial procedures.

Exclusion criteria:

• Participation in the 4 weeks (28 days) preceding the study vaccination or planned participation during the present study period in another clinical study investigating a vaccine, drug, medical device, or medical procedure.
• Receipt of any vaccine in the 4 weeks (28 days) preceding the trial vaccination or planned receipt of any vaccine prior to Visit 2 except for influenza vaccination, which might be received at least 2 weeks before or after study vaccines. This exception included monovalent pandemic influenza vaccines and multivalent influenza vaccines.
• Receipt of immune globulins, blood or blood-derived products in the past 3 months.
• Previous vaccination against meningococcal disease with either the trial vaccine or another vaccine (i.e., mono- or polyvalent, polysaccharide, or Conjugate meningococcal vaccine containing serogroups A, C, W, or Y; or meningococcal B vaccine).
• 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).
• History of meningococcal infection, confirmed either clinically, serologically, or microbiologically
• At high risk for meningococcal infection during the trial (specifically, but not limited to, participants with persistent complement deficiency, with anatomic or functional asplenia, or participants travelling to countries with high endemic or epidemic disease).
• Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the study or to a vaccine containing any of the same substances .
• Personal history of an Arthus-like reaction after vaccination with a tetanus toxoid-containing vaccine.
• Personal history of Guillain-Barré syndrome.
• Thrombocytopenia, as reported by the parent/ legally acceptable representative or suspected thrombocytopenia contraindicating intramuscular vaccination in the Investigator's opinion.
• Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination in the Investigator's opinion.
• Chronic illness that, in the opinion of the Investigator, was at a stage where it might interfere with trial conduct or completion.
• Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (temperature >= 38.0 degree Celsius). A prospective participant should not be included in the study until the condition had resolved or the febrile event had subsided.
• Receipt of oral or injectable antibiotic therapy within 72 hours prior to the first blood draw.
• Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study.

The above information was not intended to contain all considerations relevant to a participant'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

Modified double-blind: the participant (or legally acceptable representative), and the Investigator remained unaware of the treatment assignments throughout the study. An unblinded vaccine administrator administered the appropriate vaccine but was not involved in safety data collection.