Study on a MenACYW Conjugate Vaccine Administered as a Single Dose in Participants Aged 12 Months and Older in Vietnam

The MEQ00074 study is a Phase III, open-label, single-center study aimed at describing the immunogenicity and safety of a single dose of investigational quadrivalent Meningococcal Polysaccharide (serogroups A, C, W, and Y) Tetanus Toxoid Conjugate Vaccine (MenACYW conjugate vaccine) in participants aged 12 months and older in Vietnam.

The primary objectives of the study are:

* To describe the antibody responses to meningococcal serogroups A, C, W, and Y before and 30 days after the administration of a single dose of MenACYW conjugate vaccine
* To describe the safety profile of a single dose of MenACYW conjugate vaccine The duration of each participant's participation will be approximately 30 to 44 days.

The duration of each participant's participation will be approximately 30 to 44 days.

Eligibility Criteria:
Inclusion Criteria:

- Aged 12 months and above on the day of inclusion

Adults:

* Aged 18 and above on the day of inclusion
* A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:

  * Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be pre-menarche or post-menopausal for at least 1 year, or surgically sterile.
  * OR Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 4 weeks after study intervention administration.

A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine) within 1 week before the dose of study intervention.

* Informed consent form has been signed and dated
* Able to attend all scheduled visits and to comply with all study procedures

Adolescents:

* Aged 10 to 17 years on the day of inclusion
* A female participant is eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:

  * Is of non-childbearing potential. To be considered of non-childbearing potential, a female must be pre-menarche.
  * OR Is of childbearing potential and agrees to use an effective contraceptive method or abstinence from at least 4 weeks prior to study intervention administration until at least 4 weeks after study intervention administration.

A female participant of childbearing potential must have a negative highly sensitive pregnancy test (urine) within 1 week before the dose of study intervention.

* Informed consent form has been signed and dated by both the participant and the parent(s) or another legally acceptable representative and by an independent witness, if required by local regulations Assent form has been signed and dated by the participant (assent form required for participants aged 12 to 15 years) or verbal consent has been obtained (for participants aged 10 to 11 years), and informed consent form has been signed and dated by the parent(s) or another legally acceptable representative and by an independent witness, if required by local regulations
* Participant and parent/legally acceptable representative are able to attend all scheduled visits and to comply with all study procedures

Children:

* Aged 2 to 9 years on the day of inclusion
* Verbal consent has been obtained (for participants aged 7 to 9 years), and informed consent form has been signed and dated by the parent(s) or another legally acceptable representative and by an independent witness, if required by local regulations
* Participant and parent/legally acceptable representative are able to attend all scheduled visits and to comply with all study procedures

Toddlers

* Aged 12 to 23 months on the day of inclusion
* Informed consent form has been signed and dated by the parent(s) or other legally acceptable representative and by an independent witness if required by local regulations
* Participant and parent/legally acceptable representative are able to attend all scheduled visits and to comply with all study procedures

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

Adults (aged 18 years and above), Adolescents (aged 10 to 17 years), Children (aged 2 to 9 years) and Toddlers (aged 12 to 23 months)

* 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 study investigating a vaccine, drug, medical device, or medical procedure
* Receipt of any vaccine in the 4 weeks preceding the study intervention administration or planned receipt of any vaccine in the 4 weeks following study intervention administration except for influenza vaccination, which may be received at least 2 weeks before or after study vaccine. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines.
* Previous vaccination against meningococcal disease with either the trial vaccine or another vaccine (ie, polysaccharide, or conjugate meningococcal vaccine containing serogroups A, C, W, or Y; or meningococcal B serogroup-containing vaccine)
* Receipt of immune globulins, blood or blood-derived products in the past 3 months
* History of any N. meningitidis infection, confirmed either clinically, serologically, or microbiologically
* At high risk for meningococcal disease during the study (specifically but not limited to participants with persistent complement deficiency, with anatomic or functional asplenia, or participants traveling to countries with high endemic or epidemic disease)
* 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
* Personal history of Guillain-Barré syndrome (GBS)
* Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular injection
* Deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized involuntarily
* Chronic illness that, in the opinion of the Investigator, is at a stage where it might interfere with study conduct or completion
* Moderate or severe acute illness/infection (according to Investigator judgment) on the day of vaccination or febrile illness (axillary temperature ≥ 37.5 C) or hypothermia (axillary temperature ≤ 35.5 C) 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
* Receipt of oral or injectable antibiotic therapy within 72 hours prior to the first blood draw

Adults (aged 18 years and above) and Adolescents (aged 10 to 17 years)

* 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)
* Personal history of an Arthus-like reaction after vaccination with a tetanus toxoidcontaining vaccine within at least 10 years of the proposed study vaccination
* Self-reported thrombocytopenia, contraindicating intramuscular injection
* Alcohol, prescription drug, or substance abuse that, in the opinion of the Investigator, might interfere with the study conduct or completion
* 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 (ie, parent, spouse, natural or adopted child) of the Investigator or employee with direct involvement in the proposed study

Children (aged 2 to 9 years)

* 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)
* Personal history of an Arthus-like reaction after vaccination with a tetanus toxoid-containing vaccine
* Thrombocytopenia as reported by the parent/legally acceptable representative, or suspected thrombocytopenia contraindicating intramuscular injection
* Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study

Toddlers (aged 12 to 23 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 since birth)
* Personal history of an Arthus-like reaction after vaccination with a tetanus toxoid-containing vaccine
* Thrombocytopenia as reported by the parent/legally acceptable representative, or suspected thrombocytopenia contraindicating intramuscular injection
* Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study