Study to Assess the Safety and Immunogenicity of a Single Dose of a Quadrivalent Meningococcal (MenACYW) Conjugate Vaccine in Older Adults Who Received a Primary Vaccination (3 or More Years Earlier) in Study MET49
CompletedPhase 3Results postedLast updated 11 September 2025
What this trial tests
Phase 3 trial testing Meningococcal Polysaccharide (serogroups A, C, Y, and W) Tetanus Toxoid Conjugate Vaccine in Meningococcal Infection (Healthy Volunteers) in 471 participants. Completed in 25 May 2022.
59 and older, any sex, with Meningococcal Infection (Healthy Volunteers). Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Stage I: Percentage of Participants With Seroresponse for Meningococcal Serogroups A, C, W & Y Measured by Serum Bactericidal Assay Using Human Complement (hSBA) After Vaccination With MenACYW Conjugate Vaccine in Study MEQ00066: Group 1 (Menomune-primed)Primary· Day 30 (post-vaccination) in study MEQ00066
Antibody titers against meningococcal serogroups A, C, W, and Y were measured by hSBA. The hSBA vaccine seroresponse was defined as a post-vaccination hSBA titer greater than or equal to (\>=) 1:16 for participants with pre-vaccination hSBA titer less than (\<) 1:8, or a \>= 4-fold increase in hSBA titer from pre-vaccination to post-vaccination for participants with pre-vaccination hSBA titer \>= 1:8.
Serogroup A
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
60.8
51.8 – 69.2
Serogroup C
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
55.0
46.0 – 63.8
Serogroup W
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
49.2
40.4 – 58.1
Serogroup Y
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
49.2
40.4 – 58.1
Stage I: Percentage of Participants With Vaccine Seroresponse for Meningococcal Serogroups A, C, W, and Y Measured by hSBA After Vaccination With MenACYW Conjugate Vaccine in Study MEQ00066: Group 2 (MenACYW Conjugate Vaccine-primed Participants)Secondary· Day 30 (post-vaccination) in study MEQ00066
Antibody titers against meningococcal serogroups A, C, W, and Y were measured by hSBA. The hSBA vaccine seroresponse was defined as a post-vaccination hSBA titer \>= 1:16 for participants with pre-vaccination hSBA titer \< 1:8, or a \>= 4-fold increase in hSBA titer from pre-vaccination to post-vaccination for participants with pre-vaccination hSBA titer \>= 1:8.
Stage I: Percentage of Participants With Vaccine Seroresponse for Meningococcal Serogroups A, C, W, and Y Measured by hSBA at Day 6 After Vaccination With MenACYW Conjugate Vaccine in Study MEQ00066: Groups 1 and 2Secondary· Day 6 (post-vaccination) in study MEQ00066
Antibody titers against meningococcal serogroups A, C, W, and Y were measured by hSBA. The hSBA vaccine seroresponse was defined as a post-vaccination hSBA titer \>= 1:16 for participants with pre-vaccination hSBA titer \< 1:8, or a \>= 4-fold increase in hSBA titer from pre-vaccination to post-vaccination for participants with pre-vaccination hSBA titer \>= 1:8.
Serogroup A
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
Stage I: Geometric Mean Titers (GMTs) of Antibodies Against Meningococcal Serogroups A, C, W, and Y Measured by hSBA Before and After Vaccination With MenACYW Conjugate Vaccine in Study MEQ00066 (Groups 1 to 4)Secondary· Day 0 (pre-vaccination) and Day 30 (post-vaccination) in study MEQ00066
GMTs of antibodies against meningococcal serogroups A, C, W, and Y 135 were measured by hSBA. Titers are expressed in terms of 1/dilution. At Baseline, Group 1 was equivalent to Group 3 (both groups were Menomune-primed in MET49) and Group 2 was equivalent to Group 4 (both groups were MenACYW Conjugate Vaccine-primed in MET49), therefore it was planned to collect and present pooled data of Groups 1 and 3 and Groups 2 and 4 for Day 0 (pre-vaccination) in this outcome measure. Here, "0" in the number analyzed field for Day 30 signifies that data were not planned to be collected and analyzed for
Serogroup A: Day 0 (pre-vaccination)
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
Stage I: Geometric Mean Titers of Antibodies Against Meningococcal Serogroups A, C, W, and Y Measured by hSBA: Groups 5 and 6Secondary· Day 0 (pre-vaccination in MEQ00066)
GMTs of antibodies against meningococcal serogroups A, C, W, and Y were measured by hSBA. Titers were expressed in terms of 1/dilution.
Serogroup A
Group
Value
95% CI
Group 5: Menomune-primed Participants (MET44)
9.64
5.18 – 17.9
Group 6: MenACYW Conjugate Vaccine-primed Participants (MET44)
9.00
6.44 – 12.6
Serogroup C
Group
Value
95% CI
Group 5: Menomune-primed Participants (MET44)
7.58
4.11 – 14.0
Group 6: MenACYW Conjugate Vaccine-primed Participants (MET44)
11.9
7.67 – 18.5
Serogroup W
Group
Value
95% CI
Group 5: Menomune-primed Participants (MET44)
4.95
3.39 – 7.22
Group 6: MenACYW Conjugate Vaccine-primed Participants (MET44)
11.9
7.97 – 17.8
Serogroup Y
Group
Value
95% CI
Group 5: Menomune-primed Participants (MET44)
7.19
4.09 – 12.6
Group 6: MenACYW Conjugate Vaccine-primed Participants (MET44)
11.2
7.24 – 17.5
Stage I: Percentage of Participants With Antibody Titers >=1:4 and >=1:8 Against Meningococcal Serogroups A, C, W, and Y Measured by hSBA After Primary Vaccination With Menomune Vaccine or MenACYW Conjugate Vaccine: Groups 1 to 6Secondary· Day 0 (pre-vaccination) in study MEQ00066
Antibody titers against meningococcal serogroups A, C, W, and Y were measured by hSBA.
Serogroup A: >= 1:4
Group
Value
95% CI
Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
Pooled Groups 1 and 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
40.8
33.3 – 48.6
Pooled Groups 2 and 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
68.2
61.5 – 74.4
Group 5: Menomune-primed Participants (MET44)
46.2
26.6 – 66.6
Group 6: MenACYW Conjugate Vaccine-primed Participants (MET44)
59.3
45.7 – 71.9
Stage II: Geometric Mean Titers of Antibodies Against Meningococcal Serogroups A, C, W, and Y Measured by hSBA After Primary Vaccination With Menomune Vaccine or MenACYW Conjugate Vaccine: Groups 3 and 4Secondary· 5 years post primary vaccination (with Menomune or MenACYW Conjugate vaccine) in study MET49
GMTs of antibodies against meningococcal serogroups A, C, W, and Y were measured by hSBA. Titers were expressed in terms of 1/dilution.
Serogroup A
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
8.72
5.42 – 14.0
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
15.6
9.48 – 25.7
Serogroup C
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
3.78
2.59 – 5.50
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
7.25
3.68 – 14.3
Serogroup W
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
4.62
2.50 – 8.56
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
7.07
4.17 – 12.0
Serogroup Y
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
4.00
2.35 – 6.81
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
5.25
3.32 – 8.31
Stage II: Geometric Mean Titers of Antibodies Against Meningococcal Serogroups A, C, W, and Y Measured by rSBA After Primary Vaccination With Menomune Vaccine or MenACYW Conjugate Vaccine: Groups 3 and 4Secondary· 5 years post primary vaccination (with Menomune or MenACYW Conjugate vaccine) in study MET49
GMTs of antibodies against meningococcal serogroups A, C, W, and Y were measured by rSBA. Titers were expressed in terms of 1/dilution.
Serogroup A
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
24.0
6.93 – 83.0
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
40.0
12.4 – 129
Serogroup C
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
13.8
5.16 – 37.2
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
64.0
24.7 – 166
Serogroup W
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
9.79
3.37 – 28.4
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
25.0
8.48 – 73.6
Serogroup Y
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
4.00
1.84 – 8.70
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
34.5
10.9 – 109
Stage II: Percentage of Participants With Antibody Titers >=1:4 and >=1:8 Against Meningococcal Serogroups A, C, Y, and W Measured by hSBA After Primary Vaccination With Menomune Vaccine or MenACYW Conjugate Vaccine: Groups 3 and 4Secondary· 5 years post primary vaccination (with Menomune or MenACYW Conjugate vaccine) in study MET49
Antibody titers against meningococcal serogroups A, C, W, and Y were measured by hSBA.
Serogroup A: >= 1:4
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
79.2
57.8 – 92.9
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
89.3
71.8 – 97.7
Serogroup A: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
58.3
36.6 – 77.9
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
78.6
59.0 – 91.7
Serogroup C: >= 1:4
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
50.0
29.1 – 70.9
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
64.3
44.1 – 81.4
Serogroup C: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
20.8
7.1 – 42.2
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
28.6
13.2 – 48.7
Serogroup W: >= 1:4
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
33.3
15.6 – 55.3
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
64.3
44.1 – 81.4
Serogroup W: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
29.2
12.6 – 51.1
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
46.4
27.5 – 66.1
Serogroup Y: >= 1:4
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
37.5
18.8 – 59.4
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
50.0
30.6 – 69.4
Serogroup Y: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
29.2
12.6 – 51.1
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
42.9
24.5 – 62.8
Stage II: Percentage of Participants With Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Measured by rSBA After Primary Vaccination With Menomune Vaccine or MenACYW Conjugate Vaccine: Groups 3 and 4Secondary· 5 years post primary vaccination (with Menomune or MenACYW Conjugate vaccine) in study MET49
Antibody titers against meningococcal serogroups A, C, W, and Y were measured by rSBA.
Serogroup A: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
45.8
25.6 – 67.2
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
53.6
33.9 – 72.5
Serogroup A: >= 1:128
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
41.7
22.1 – 63.4
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
50.0
30.6 – 69.4
Serogroup C: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
45.8
25.6 – 67.2
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
75.0
55.1 – 89.3
Serogroup C: >= 1:128
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
25.0
9.8 – 46.7
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
53.6
33.9 – 72.5
Serogroup W: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
29.2
12.6 – 51.1
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
50.0
30.6 – 69.4
Serogroup W: >= 1:128
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
29.2
12.6 – 51.1
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
46.4
27.5 – 66.1
Serogroup Y: >= 1:8
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
12.5
2.7 – 32.4
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
50.0
30.6 – 69.4
Serogroup Y: >= 1:128
Group
Value
95% CI
Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
12.5
2.7 – 32.4
Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
50.0
30.6 – 69.4
Adverse events — posted to ClinicalTrials.gov
Time frame: Unsolicited adverse event (AE) data were collected from Day 0 (pre-vaccination) up to Day 30 (post-vaccination). The solicited reactions (SR) were collected within 7 days post-vaccination. Serious AEs data were collected throughout the study (i.e., up to 30 days post-vaccination for Groups 1 and 2; and 2 years post-vaccination for Groups 3 and 4 in the current study).
Reporting threshold: 5%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
Stage I - Group 1: MenACYW Conjugate Vaccine (MET 49 - Menomune-primed Participants)
Serious: 2/151 (1%)
Deaths: 0/151
Stage I - Group 2: MenACYW Conjugate Vaccine (MET49 - MenACYW Conjugate Vaccine-primed Participants)
Serious: 1/162 (1%)
Deaths: 0/162
Stage II - Group 3: MenACYW Conjugate Vaccine (MET49: Menomune-primed Participants)
Serious: 0/27 (0%)
Deaths: 0/27
Stage II - Group 4: MenACYW Conjugate Vaccine (MET49: MenACYW-primed Participants)
Serious: 1/25 (4%)
Deaths: 0/25
Serious adverse events (4 terms)
Reaction
System
Stage I - Group 1: MenACYW…
Stage I - Group 2: MenACYW…
Stage II - Group 3: MenACY…
Stage II - Group 4: MenACY…
Diverticulitis
Infections and infestations
—
—
—
—
Osteoarthritis
Musculoskeletal and connective tissue disorders
—
—
—
—
Epithelioid Mesothelioma
Neoplasms benign, malignant and unspecified (incl cysts and polyps)
Primary Objective:
To demonstrate sufficiency of the vaccine seroresponse to meningococcal serogroups A, C, W, and Y following administration of a single dose of Meningococcal Polysaccharide (Serogroups A, C, Y, and W 135) Tetanus Toxoid (MenACYW) Conjugate vaccine to Group 1 participants (who received primary vaccination with Menomune vaccine greater than or equal to \[\>= 3\] years earlier at \>= 56 years of age in Study MET49).
Secondary Objectives:
Secondary Objective 1 - To demonstrate sufficiency of the vaccine seroresponse to meningococcal serogroups A, C, W, and Y following administration of a single dose of MenACYW Conjugate vaccine to Group 2 participants (who received primary vaccination with MenACYW Conjugate vaccine \>= 3 years earlier at \>= 56 years of age in Study MET49).
Secondary Objective 2 - To describe vaccine seroresponse rates with respect to serogroups A, C, W, and Y in serum specimens collected 6 days (window, 5-7) post-vaccination in approximately 60 participants from Group 1 (Menomune-primed) and approximately 60 participants from Group 2 (MenACYW Conjugate vaccine-primed).
Secondary Objective 3 - To describe antibody persistence \>= 3 years after primary vaccination with Menomune vaccine or MenACYW Conjugate vaccine for participants from all groups.
Publications & conference data
8 peer-reviewed publications reference this trial (live from Europe PMC):
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Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Sanofi Pasteur, a Sanofi Company
Last refreshed: 11 September 2025
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT04142242.