This will be a Phase III, modified double-blind (open-label for toddlers in India), randomized, parallel-group, active-controlled, step-wise, multi-center study to compare and describe the immunogenicity and safety of MenACYW conjugate vaccine when administered as a single dose in healthy adults, adolescents, children, and toddlers in India and a modified double-blind, randomized, parallel-group, active-controlled, multi-center study to compare and describe the immunogenicity and safety of MenACYW conjugate vaccine when administered as a single dose in healthy adolescents and children in RSA.

Study duration per participant is approximately 31 to 45 days

Inclusion Criteria:

- Age in the defined range on the day of inclusion: For Adults: Aged ≥ 18 years on the day of inclusion For Children and Adolescents: Aged 2 to 17 years on the day of inclusion For Toddlers: Aged 12 to 23 months† on the day of inclusion

- Z-score of ≥ -2 standard deviations (SD) on the Weight-for-height table of the World Health Organization (WHO) Child Growth Standards: For toddlers and children: Toddlers aged 12 to 23 months and Children aged 2 to 5 years had a Z-score of ≥ -2 SD on the Weight-for-height table of the WHO Child Growth Standards

• Informed consent obtained For adults: Informed consent form has been signed and dated by the subject and by an independent witness, if required by local regulations For toddlers, children, and adolescents: Assent form has been signed and dated by the subject (for subjects 7 to 17 years of age), and informed consent form has been signed and dated by the parent(s) or legally acceptable representative and by an independent witness, if required by local regulations
• Were able to attend all scheduled visits and to comply with all trial procedures For adults: Were able to attend all scheduled visits and to comply with all trial procedures For toddlers, children, and adolescents: Participants and parent / legally acceptable representative were able to attend all scheduled visits and to comply with all trial procedures
• For Toddlers: All toddlers were due to receive an age-recommended RPV on D0

Exclusion Criteria:

• Participant was pregnant, or lactating, or of childbearing potential and was not using an effective method of contraception or abstinence from at least 4 weeks prior to vaccination until at least 4 weeks after vaccination. To be considered of non-childbearing potential, a female must be pre-menarche, or post-menopausal for at least 1 year, or surgically sterile
• Participation at the time of study enrollment (or in the 4 weeks preceding the trial vaccination) or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure
• Receipt of any vaccine in the 4 weeks (28 days) preceding the IMP or planned receipt of any vaccine in the 4 weeks following vaccination except for oral poliovirus vaccine (OPV) in India, received during national immunization days. In India, OPV might have been received with a gap of at least 2 weeks before the IMP. This exception included monovalent and bivalent OPV.
• Previous vaccination against meningococcal disease with either the IMP or another vaccine (i.e., mono- or polyvalent, polysaccharide, or conjugate meningococcal vaccine containing serogroups A, C, Y, or W; or meningococcal B serogroup containing vaccine)
• Receipt of immune globulins, blood or blood-derived products in the past 3 months
• 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, subjects with persistent complement deficiency, with anatomic or functional asplenia, or subjects traveling to countries with high endemic or epidemic disease)
• Known systemic hypersensitivity to latex or to any of the vaccine components, or history of a life-threatening reaction to the vaccine(s) used in the trial or to a vaccine containing any of the same substances
• Verbal report of thrombocytopenia, as reported by the subject or the subject's parent / legally acceptable representative, 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
• Personal history of Guillain-Barré syndrome
• Personal history of an Arthus-like reaction after vaccination with a tetanus toxoid-containing vaccine within 10 years of the proposed study vaccination
• Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily
• Current alcohol abuse or drug addiction
• Chronic illness that, in the opinion of the investigator, was at a stage where it might interfere with trial conduct or completion
• Any condition which, in the opinion of the Investigator, might have interfered with the evaluation of the study objectives.
• Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination, febrile illness (temperature ≥ 38.0°C), persistent diarrhea, vomiting. A prospective subject was not included in the study until the condition has been resolved or the febrile event has been subsided
• Receipt of oral or injectable antibiotic therapy within 72 hours prior to the first blood draw
• Identified as an Investigator or employee of the Investigator or study center with direct involvement in the proposed study, or identified as an immediate family member (i.e., parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study

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

This trial is a modified double-blind trial (except for toddlers in India), which means that the participant's parent / legally acceptable representative, the Investigator, and other study personnel remain unaware of the treatment assignments throughout the trial. An unblinded vaccine administrator administer the appropriate vaccine but is not involved in safety data collection. The Sponsor and laboratory personnel performing the serology testing are also blinded to treatment assignments throughout the trial until database lock.

It will be open-label for toddlers population in India.