The aim of the study was to describe the safety and antibody response to booster administration with Meningococcal Polysaccharide (Serogroups A, C, Y and W) Tetanus Toxoid (MenACYW) Conjugate vaccine in participants who received their first quadrivalent meningococcal Conjugate vaccine dose in the past 4-10 years.

Primary Objective:

• To demonstrate the non-inferiority of the vaccine seroresponse of meningococcal serogroups A, C, Y, and W following the administration of a booster dose of MenACYW Conjugate vaccine compared to those observed following the administration of a booster dose of Menactra® in participants who were first vaccinated with 1 dose of a quadrivalent meningococcal vaccine 4 to 10 years before the booster dose.

Secondary Objectives:

• To evaluate the vaccine seroresponse of meningococcal serogroups A, C, Y, and W measured using human serum bactericidal assay (hSBA) in serum specimens collected 6 days after vaccination in a subset of 120 participants.
• To evaluate the antibody responses (geometric mean titers) to serogroups A, C, Y, and W measured using hSBA on Day 0 (pre-vaccination) and Day 30 after vaccination.

Observational Objectives:

• To describe the antibody titers against meningococcal serogroups A, C, Y, and W measured by hSBA assessed at Day 0, Day 6, and Day 30 days after vaccination.
• To describe the antibody responses to the meningococcal serogroups A, C, Y, and W before and 30 days after vaccination with MenACYW Conjugate vaccine or Menactra® measured by rabbit serum bactericidal assay (rSBA) in a subset of participants.
• To describe the safety profile of MenACYW Conjugate vaccine compared to that of a licensed Menactra® after booster vaccination.

Healthy adolescents and adults who had received 1 dose of a quadrivalent meningococcal Conjugate vaccine 4 to 10 years previously were randomized to receive either 1 dose of MenACYW Conjugate vaccine or licensed Menactra®. All participants underwent immunogenicity assessment at baseline (pre-vaccination) and post-vaccination and were also evaluated for safety up to Day 180 post-vaccination. In addition, a subset had an additional blood sample collected at 6 days post-vaccination for immunogenicity assessment.

Inclusion Criteria:

• Aged >= 15 years on the day of inclusion.
• Participant has documented record of having received 1 dose of a quadrivalent meningococcal conjugate vaccine 4 to 10 years prior to study vaccination.
• Participant aged 15 to < 18 years: assent form signed and dated by the participant and informed consent form (ICF) signed and dated by the parent or guardian.
• Participant aged >=18 years: ICF signed and dated by the participant.
• Participants aged 15 to < 18 years: both the participant and parent / guardian were able to attend all scheduled visits and to comply with all trial procedures.
• Participants aged >= 18 years: able to attend all scheduled visits and to comply with all trial procedures.

Exclusion Criteria:

• Participant was pregnant, lactating, or of childbearing potential (to be considered of non-childbearing potential, a female must be pre-menarche or post-menopausal for at least 1 year, surgically sterile, or using an effective method of contraception or abstinence from at least 4 weeks prior to vaccination until at least 4 weeks after vaccination).
• Participation 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 trial vaccination or planned receipt of any vaccine before Day 30 visit except for influenza vaccination, which may be received at least 2 weeks before study investigational vaccines. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines.
• Previous vaccination against meningococcal disease with either an investigational or approved meningococcal B 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, 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 vaccine(s) used in the trial 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.
• Verbal report of 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.
• 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, is at a stage where it might interfere with trial conduct or completion.
• Moderate or severe acute illness/infection (according to the Investigator's judgment) on the day of vaccination or febrile illness (temperature >= 100.4°Fahrenheit [F]). A prospective participant should not be included in the study until the condition has resolved or the febrile event has 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