Meningococcal InfectionPhase 3NCT06228586

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

A Phase 3 study testing Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate Vaccine in people with Meningococcal Infection and Healthy Volunteers, run by Sanofi Pasteur, a Sanofi Company at 4 sites in Vietnam.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The MEQ00074 study was 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… Read more about this study

Who is it for?: Ages 12 months and olderHealthy volunteers can take part
Conditions the study is for: Meningococcal Infection, Healthy Volunteers
What is being tested?: Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate Vaccine
Type of treatment: Vaccines, Injection or infusion
Could I receive a placebo?: No, everyone receives an active treatment
How many people: 447 participants
Where: 4 sitesVietnam
Study dates: 18 Jan 2024to 31 Mar 2024
Phase: Phase 3
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 12 months and older
All sexes
Healthy volunteers accepted
Child, Adult, Older adult

Who may be able to join

Aged 12 months and above on the day of inclusion
Adults:
Aged 18 and above on the day of inclusion
A female participant was eligible to participate if she was not pregnant or breastfeeding and one of the following conditions applies:
Was 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 Was of childbearing potential and agreed 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.

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A female participant of childbearing potential would have a negative highly sensitive pregnancy test (urine) within 1 week before the dose of study intervention.
Informed consent form was signed and dated
Was 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 was eligible to participate if she is not pregnant or breastfeeding and one of the following conditions applies:
Was of non-childbearing potential. To be considered of non-childbearing potential, a female must be pre-menarche.
OR Was 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 would have a negative highly sensitive pregnancy test (urine) within 1 week before the dose of study intervention.
Informed consent form was 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 was signed and dated by the participant (assent form required for participants aged 12 to 15 years) or verbal consent was obtained (for participants aged 10 to 11 years), and informed consent form was 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 were 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 was obtained (for participants aged 7 to 9 years), and informed consent form was 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 were 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

Who cannot join

Participants were 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

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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

Trial locations and contacts

4 sites in 1 country.

Vietnam4 sites

Investigational Site Number : 7040001
Hanoi
Investigational Site Number : 7040002
Thái Bình, 410000
Investigational Site Number : 7040003
Thái Bình, 70000
Investigational Site Number : 7040004
Thái Bình, 70000

Other trials in Vietnam

About this study

Official title: A Phase III, Open-label, Single-center Study to Describe the Immunogenicity and Safety of a Single Dose of MenACYW Conjugate Vaccine in Participants Aged 12 Months and Older in Vietnam

The primary objectives of the study were:

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.

Read the detailed description

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

Conditions: Meningococcal Infection, Healthy Volunteers
Being tested: Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate Vaccine
Medical subject headings: Meningococcal Infections

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate VaccineBiological
Also called MenACYW conjugate vaccine, MenQuadfi™
Pharmaceutical form:Liquid solution-Route of administration:Intramuscular injection

Study groups in NCT06228586
Study group	Role	What they receive
MenACYW conjugate vaccine	Experimental	MenACYW conjugate vaccine single injection on Day 01 Receives: Biological: Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate Vaccine

What is being measured

The primary outcome is the main question the study is designed to answer.

Geometric Mean Titers (GMTs) of Antibodies Against Meningococcal Serogroups A, C, Y, and W
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay utilizing the human complement (hSBA).
Measured: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Titers >=4-Fold Rise From Pre-Vaccination to Post-Vaccination
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured by hSBA. Percentages are rounded off to the tenth decimal place.
Measured: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Titers >=1:4 and >=1:8
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured by hSBA. Percentages are rounded off to the tenth decimal place.
Measured: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Vaccine Seroresponse for Serogroups A, C, Y, and W
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured by hSBA. hSBA vaccine seroresponse was defined as follows: for a participant with a pre-vaccination titer <1:8, the post-vaccination titer must be >=1:16, and for a participant with a pre-vaccination titer >=1:8, the post-vaccination titer must be at least 4-fold greater than the pre-vaccination titer. Percentages are rounded off to the tenth decimal place.
Measured: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the case report form (CRF) in terms of diagnosis and onset window post-vaccination. Immediate events were recorded to capture medically relevant unsolicited systemic AEs (including those related to the study vaccine administered) which occurred within the first 30 minutes after vaccination.
Measured: Up to 30 minutes post-vaccination on Day 1
Number of Participants With Solicited Injection Site Reactions and Systemic Reactions
A solicited reaction was an "expected" adverse reaction (AR) (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. An injection site reaction was an AR at and around the injection site considered to be related to the study vaccine administered and were commonly inflammatory reactions. Systemic ARs were all ARs that were not injection site reactions and included systemic manifestations such as headache, fever, as well as localized or topical manifestations.
Measured: From the study vaccine administration (Day 1) up to 7 days post-vaccination, up to Day 8
Number of Participants With Unsolicited Non-Serious Adverse Events
An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.
Measured: From the study vaccine administration (Day 1) up to 30 days post-vaccination (Day 31)
Number of Participants With Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs)
An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An SAE was any AE that, at any dose, resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or was other medically important event. An AESI (serious or non-serious) was one of scientific and medical concern specific to the Sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the investigator to the Sponsor was appropriate.
Measured: From the study vaccine administration (Day 1) up to 30 days post-vaccination (Day 31)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

18 Jan 202431 Mar 2024

First posted29 Jan 2024
Study start18 Jan 2024
Primary completion31 Mar 2024
Study completion31 Mar 2024

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Publications (1)Papers the sponsor has linked to this study.
Other trials for Meningococcal InfectionStudies of the same condition, open and under way.
More trials run by Sanofi Pasteur, a Sanofi CompanyThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 3
Primary purpose: Prevention
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Enrolment: 447 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT06228586
Sponsor's protocol ID: MEQ00074
Other IDs: U1111-1256-9172, 2021-001699-41
Status last verified: Aug 2025
First submitted: 18 Jan 2024
Last updated: 17 Sep 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: Yes: 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
Expanded access: Available

Publications

Thiem VD, Janicot S, Syrkina O, Ha VH, Long PD, Nguyen DT, Zocchetti C. Immunogenicity and Safety of Single-Dose MenACYW Conjugate Vaccine in Vietnamese Participants Aged >/= 12 Months: A Phase III, Open-Label Study. Infect Dis Ther. 2026 Oct 12. doi: 10.1007/s40121-026-01458-6. Online ahead of print.
PubMed 42862517

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Meningococcal Infection trials

Study at a glance

From the registry record, last updated by the sponsor on 17 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: A Phase III, Open-label, Single-center Study to Describe the Immunogenicity and Safety of a Single Dose of MenACYW Conjugate Vaccine in Participants Aged 12 Months and Older in Vietnam
ClinicalTrials.gov ID: NCT06228586
Acronym / sponsor ID: MEQ00074
Conditions: Meningococcal Infection, Healthy Volunteers
Phase: Phase 3
Study type: Interventional
Recruitment status: Completed
Enrolment: 447 participants (actual)
Lead sponsor: Sanofi Pasteur, a Sanofi CompanyIndustry (pharma, biotech, devices)
Study start: 18 Jan 2024 (actual)
Primary completion: 31 Mar 2024 (actual)
Study completion: 31 Mar 2024 (actual)
First posted: 29 Jan 2024 (actual)
Results: Posted 17 Sep 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The primary objectives of the study were:

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.

Detailed description

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

Study design

Primary purpose: Prevention
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1

Arm	Type	Receives
MenACYW conjugate vaccine	Experimental	Biological: Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate VaccineMenACYW conjugate vaccine single injection on Day 01

Who may qualify

Ages: 12 months and older
Sex: All
Healthy volunteers: Accepted
Age groups: Child, Adult, Older adult

Key inclusion criteria (25 listed)

Aged 12 months and above on the day of inclusion
Aged 18 and above on the day of inclusion
A female participant was eligible to participate if she was not pregnant or breastfeeding and one of the following conditions applies:
A female participant of childbearing potential would have a negative highly sensitive pregnancy test (urine) within 1 week before the dose of study intervention.
Informed consent form was signed and dated

Key exclusion criteria (31 listed)

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

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Meningococcal Polysaccharide (Serogroups A, C, W, and Y) Tetanus Toxoid Conjugate VaccineAlso: MenACYW conjugate vaccine, MenQuadfi™Pharmaceutical form:Liquid solution-Route of administration:Intramuscular injection	Biological	MenACYW conjugate vaccine

Primary outcome

Geometric Mean Titers (GMTs) of Antibodies Against Meningococcal Serogroups A, C, Y, and W
Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay utilizing the human complement (hSBA).
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Titers >=4-Fold Rise From Pre-Vaccination to Post-Vaccination
Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured by hSBA. Percentages are rounded off to the tenth decimal place.
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Titers >=1:4 and >=1:8
Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured by hSBA. Percentages are rounded off to the tenth decimal place.
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Vaccine Seroresponse for Serogroups A, C, Y, and W
Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured by hSBA. hSBA vaccine seroresponse was defined as follows: for a participant with a pre-vaccination titer <1:8, the post-vaccination titer must be >=1:16, and for a participant with a pre-vaccination titer >=1:8, the post-vaccination titer must be at least 4-fold greater than the pre-vaccination titer. Percentages are rounded off to the tenth decimal place.
Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)
Time frame: Up to 30 minutes post-vaccination on Day 1
An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the case report form (CRF) in terms of diagnosis and onset window post-vaccination. Immediate events were recorded to capture medically relevant unsolicited systemic AEs (including those related to the study vaccine administered) which occurred within the first 30 minutes after vaccination.
Number of Participants With Solicited Injection Site Reactions and Systemic Reactions
Time frame: From the study vaccine administration (Day 1) up to 7 days post-vaccination, up to Day 8
A solicited reaction was an "expected" adverse reaction (AR) (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. An injection site reaction was an AR at and around the injection site considered to be related to the study vaccine administered and were commonly inflammatory reactions. Systemic ARs were all ARs that were not injection site reactions and included systemic manifestations such as headache, fever, as well as localized or topical manifestations.
Number of Participants With Unsolicited Non-Serious Adverse Events
Time frame: From the study vaccine administration (Day 1) up to 30 days post-vaccination (Day 31)
An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An unsolicited AE was an observed AE that did not fulfill the conditions of solicited reactions, i.e., pre-listed in the CRF in terms of diagnosis and onset window post-vaccination.
Number of Participants With Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs)
Time frame: From the study vaccine administration (Day 1) up to 30 days post-vaccination (Day 31)
An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study vaccine, whether or not considered related to the study vaccine. An SAE was any AE that, at any dose, resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or was other medically important event. An AESI (serious or non-serious) was one of scientific and medical concern specific to the Sponsor's study vaccine or program, for which ongoing monitoring and rapid communication by the investigator to the Sponsor was appropriate.

Results and safety

Results posted to the registry on 17 Sep 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
MenACYW Conjugate Vaccine: 12-23 Months of Age	223	220
MenACYW Conjugate Vaccine: 24 Months of Age and Above	224	223

Primary outcome: Geometric Mean Titers (GMTs) of Antibodies Against Meningococcal Serogroups A, C, Y, and W

Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1). Geometric mean (95% Confidence Interval). Unit: titer

Measure	MenACYW Conjugate Vaccine: 12-23 Months of Age n = 200	MenACYW Conjugate Vaccine: 24 Months of Age and Above n = 221
Serogroup A: Day 1	4.44 (4.00 to 4.92)	7.58 (6.76 to 8.51)
Serogroup A: Day 31	39.0 (32.9 to 46.2)	43.2 (34.6 to 54.1)
Serogroup C: Day 1	2.61 (2.34 to 2.91)	5.65 (4.82 to 6.62)
Serogroup C: Day 31	1226 (1076 to 1398)	895 (781 to 1026)
Serogroup Y: Day 1	2.86 (2.55 to 3.20)	4.08 (3.47 to 4.78)
Serogroup Y: Day 31	132 (112 to 156)	288 (244 to 340)
Serogroup W: Day 1	2.26 (2.09 to 2.44)	4.33 (3.81 to 4.92)
Serogroup W: Day 31	99.4 (85.6 to 115)	166 (139 to 198)

Population analysed: Analysis was performed on the per-protocol analysis set (PPAS) which was a subset of the full analysis set (FAS). The FAS included participants who received the study vaccine and had a valid post-vaccination serology result.

Primary outcome: Percentage of Participants With Serum Bactericidal Assay Using Human Complement Titers >=4-Fold Rise From Pre-Vaccination to Post-Vaccination

Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1). Number (95% Confidence Interval). Unit: percentage of participants

Measure	MenACYW Conjugate Vaccine: 12-23 Months of Age n = 200	MenACYW Conjugate Vaccine: 24 Months of Age and Above n = 221
Serogroup A	81.5 (75.4 to 86.6)	66.5 (59.9 to 72.7)
Serogroup C	99.5 (97.2 to 100)	97.7 (94.8 to 99.3)
Serogroup Y	96.5 (92.9 to 98.6)	95.5 (91.8 to 97.8)
Serogroup W	94.5 (90.4 to 97.2)	95.5 (91.8 to 97.8)

Population analysed: Analysis was performed on the PPAS which was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result.

Primary outcome: Percentage of Participants With Serum Bactericidal Assay Using Human Complement Titers >=1:4 and >=1:8

Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1). Number (95% Confidence Interval). Unit: percentage of participants

Measure	MenACYW Conjugate Vaccine: 12-23 Months of Age n = 200	MenACYW Conjugate Vaccine: 24 Months of Age and Above n = 221
Serogroup A: Day 1: >=1:4	79.5 (73.2 to 84.9)	94.1 (90.2 to 96.8)
Serogroup A: Day 1: >=1:8	25.0 (19.2 to 31.6)	59.7 (52.9 to 66.3)
Serogroup A: Day 31: >=1:4	97.5 (94.3 to 99.2)	89.1 (84.3 to 92.9)
Serogroup A: Day 31: >=1:8	93.5 (89.1 to 96.5)	84.6 (79.2 to 89.1)
Serogroup C: Day 1: >=1:4	16.5 (11.6 to 22.4)	64.3 (57.6 to 70.6)
Serogroup C: Day 1: >=1:8	8.5 (5.0 to 13.3)	38.5 (32.0 to 45.2)
Serogroup C: Day 31: >=1:4	100 (98.2 to 100)	100 (98.3 to 100)
Serogroup C: Day 31: >=1:8	100 (98.2 to 100)	100 (98.3 to 100)

Population analysed: Analysis was performed on the PPAS which was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result.

Primary outcome: Percentage of Participants With Serum Bactericidal Assay Using Human Complement Vaccine Seroresponse for Serogroups A, C, Y, and W

Time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1). Number (95% Confidence Interval). Unit: percentage of participants

Measure	MenACYW Conjugate Vaccine: 12-23 Months of Age n = 200	MenACYW Conjugate Vaccine: 24 Months of Age and Above n = 221
Serogroup A	81.5 (75.4 to 86.6)	66.5 (59.9 to 72.7)
Serogroup C	99.5 (97.2 to 100)	97.7 (94.8 to 99.3)
Serogroup Y	96.5 (92.9 to 98.6)	95.5 (91.8 to 97.8)
Serogroup W	94.5 (90.4 to 97.2)	95.5 (91.8 to 97.8)

Population analysed: Analysis was performed on the PPAS which was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result.

Adverse events

Time frame: AEs, SAEs and all-cause mortality (deaths) were collected from the study vaccine administration (Day 1) up to 30 days post-vaccination (Day 31). Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
MenACYW Conjugate Vaccine: 12-23 Months of Age	3 of 223 (1.3%)	59 of 223 (26.5%)	0 of 223
MenACYW Conjugate Vaccine: 24 Months of Age and Above	2 of 223 (0.9%)	39 of 223 (17.5%)	0 of 223

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Derived from this study: PubMed 42862517Thiem VD, Janicot S, Syrkina O, Ha VH, Long PD, Nguyen DT, Zocchetti C. Immunogenicity and Safety of Single-Dose MenACYW Conjugate Vaccine in Vietnamese Participants Aged >/= 12 Months: A Phase III, Open-Label Study. Infect Dis Ther. 2026 Oct 12. doi: 10.1007/s40121-026-01458-6. Online ahead of print.
MEQ00074 Plain Language Results SummaryLink provided by the sponsor.
Individual participant dataSharing planned: Yes. 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

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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

4 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 25 inclusion and 31 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 17 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 4 sites in Vietnam. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 17 Sep 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Geometric Mean Titers (GMTs) of Antibodies Against Meningococcal Serogroups A, C, Y, and W (time frame: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)). The study lists 8 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06228586, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2025.