Trial Outcomes & Findings for Study of Immunogenicity and Safety of MenQuadfi® as a Booster Vaccine in Toddlers 12 to 23 Months, Regardless of the Quadrivalent Meningococcal Conjugate Vaccine Used for Priming in Infancy (NCT NCT05929651)

NCT ID: NCT05929651

Last Updated: 2025-09-22

Results Overview

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using human complement (hSBA). Percentages are rounded to the nearest tenth.

• Recruitment status: COMPLETED
• Study phase: PHASE4
• Target enrollment: 71 participants
• Primary outcome timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)
• Results posted on: 2025-09-22

Participant Flow

This study was conducted at 2 investigational sites in Argentina between 07 September 2023 to 09 September 2024.

A total of 71 participants were enrolled in this study.

Participant milestones

Measure	MenACYW Conjugate Vaccine Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 milliliter \[mL\]) of meningococcal polysaccharide (serogroups A, C, W, and Y) tetanus toxoid (MenACYW conjugate vaccine) as an intramuscular (IM) injection at Day 1.
Overall Study STARTED	71
Overall Study Safety Analysis Set (SafAS)	69
Overall Study COMPLETED	68
Overall Study NOT COMPLETED	3

Reasons for withdrawal

Measure	MenACYW Conjugate Vaccine Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 milliliter \[mL\]) of meningococcal polysaccharide (serogroups A, C, W, and Y) tetanus toxoid (MenACYW conjugate vaccine) as an intramuscular (IM) injection at Day 1.
Overall Study Protocol Deviation	1
Overall Study Withdrawal by participant's parents/legally acceptable representatives	2

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Measure	MenACYW Conjugate Vaccine n=71 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Age, Continuous	14.3 months STANDARD_DEVIATION 1.50 • n=71 Participants
Sex: Female, Male Female	34 Participants n=71 Participants
Sex: Female, Male Male	37 Participants n=71 Participants

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The per-protocol analysis set (PPAS) 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. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using human complement (hSBA). Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=64 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: Day 1	72.1 Percentage of participants Interval 59.2 to 82.9
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: Day 31	100 Percentage of participants Interval 93.8 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: Day 1	60.3 Percentage of participants Interval 47.2 to 72.4
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: Day 31	100 Percentage of participants Interval 94.1 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: Day 1	67.7 Percentage of participants Interval 54.7 to 79.1
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: Day 31	100 Percentage of participants Interval 93.2 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: Day 1	73.4 Percentage of participants Interval 60.9 to 83.7
Percentage of Participants With Serum Bactericidal Assay Using Human Complement (hSBA) Antibody Titers >=1:8 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: Day 31	100 Percentage of participants Interval 93.8 to 100.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using human complement (hSBA).

Outcome measures

Measure	MenACYW Conjugate Vaccine n=64 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup A: Day 1	14.0 Titer Interval 10.1 to 19.4
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup A: Day 31	244 Titer Interval 163.0 to 366.0
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup C: Day 1	12.3 Titer Interval 8.29 to 18.2
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup C: Day 31	1072 Titer Interval 805.0 to 1426.0
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup Y: Day 1	14.0 Titer Interval 9.7 to 20.2
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup Y: Day 31	945 Titer Interval 683.0 to 1309.0
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup W: Day 1	16.9 Titer Interval 11.8 to 24.2
Geometric Mean Titers (GMTs) Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Assay Using Human Complement Serogroup W: Day 31	953 Titer Interval 712.0 to 1275.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using human complement (hSBA). Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=64 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: Day 31	100 Percentage of participants Interval 93.8 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: Day 1	96.7 Percentage of participants Interval 88.7 to 99.6
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: Day 31	100 Percentage of participants Interval 93.8 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: Day 1	76.2 Percentage of participants Interval 63.8 to 86.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: Day 31	100 Percentage of participants Interval 94.1 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: Day 1	85.5 Percentage of participants Interval 74.2 to 93.1
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: Day 31	100 Percentage of participants Interval 93.2 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=1:4 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: Day 1	87.5 Percentage of participants Interval 76.8 to 94.4

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using human complement (hSBA). Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=59 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup A	91.1 Percentage of participants Interval 80.4 to 97.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup C	100 Percentage of participants Interval 93.9 to 100.0
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup Y	96.1 Percentage of participants Interval 86.5 to 99.5
Percentage of Participants With Serum Bactericidal Assay Using Human Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup W	100 Percentage of participants Interval 93.7 to 100.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using human complement (hSBA). hSBA vaccine seroresponse was defined for a participant with a pre-vaccination titer <1:8 as a post-vaccination titer of >=1:16 and for a participant with a pre-vaccination titer >=1:8 as a post-vaccination titer that is at least 4-fold greater than the pre-vaccination titer. Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=59 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Assay Using Human Complement Serogroup A	91.1 Percentage of participants Interval 80.4 to 97.0
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Assay Using Human Complement Serogroup C	100 Percentage of participants Interval 93.9 to 100.0
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Assay Using Human Complement Serogroup Y	96.1 Percentage of participants Interval 86.5 to 99.5
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Assay Using Human Complement Serogroup W	100 Percentage of participants Interval 93.7 to 100.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using baby rabbit complement (rSBA).

Outcome measures

Measure	MenACYW Conjugate Vaccine n=64 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup W: Day 31	9329 Titer Interval 6627.0 to 13132.0
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup A: Day 1	82.3 Titer Interval 33.3 to 203.0
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup A: Day 31	4715 Titer Interval 3547.0 to 6268.0
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup C: Day 1	11.6 Titer Interval 6.54 to 20.7
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup C: Day 31	3676 Titer Interval 2707.0 to 4990.0
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup Y: Day 1	30.9 Titer Interval 15.6 to 61.2
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup Y: Day 31	5198 Titer Interval 4091.0 to 6604.0
Geometric Mean Titers Against Meningococcal Serogroups A, C, Y, and W as Measured by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement (rSBA) Serogroup W: Day 1	28.0 Titer Interval 14.7 to 53.5

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using baby rabbit complement (rSBA). Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=64 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: >=1:8: Day 1	56.4 Percentage of participants Interval 42.3 to 69.7
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: >=1:128: Day 1	54.5 Percentage of participants Interval 40.6 to 68.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: >=1:8: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup A: >=1:128: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: >=1:8: Day 1	39.3 Percentage of participants Interval 27.1 to 52.7
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: >=1:128: Day 1	24.6 Percentage of participants Interval 14.5 to 37.3
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: >=1:8: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup C: >=1:128: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: >=1:8: Day 1	55.9 Percentage of participants Interval 42.4 to 68.8
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: >=1:128: Day 1	44.1 Percentage of participants Interval 31.2 to 57.6
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: >=1:8: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup Y: >=1:128: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: >=1:8: Day 1	61.9 Percentage of participants Interval 48.8 to 73.9
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: >=1:128: Day 1	41.3 Percentage of participants Interval 29.0 to 54.4
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: >=1:8: Day 31	100 Percentage of participants Interval 94.4 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=1:8 and >=1:128 Against Meningococcal Serogroups A, C, Y, and W Serogroup W: >=1:128: Day 31	100 Percentage of participants Interval 94.4 to 100.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using baby rabbit complement (rSBA). Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=62 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup W	100 Percentage of participants Interval 94.2 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup A	83.3 Percentage of participants Interval 70.7 to 92.1
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup C	98.3 Percentage of participants Interval 91.1 to 100.0
Percentage of Participants With Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Antibody Titers >=4-Fold Rise From Pre-vaccination to Post-Vaccination Serogroup Y	98.3 Percentage of participants Interval 90.8 to 100.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Functional meningococcal antibody activity against serogroups A, C, Y, and W was measured in a serum bactericidal assay using baby rabbit complement (rSBA). rSBA vaccine seroresponse was defined for a participant with a pre-vaccination titer <1:8 as a post-vaccination titer of >=1:32 and for a participant with a pre-vaccination titer >=1:8 as a post-vaccination titer that is at least 4-fold greater than the pre-vaccination titer. Percentages are rounded to the nearest tenth.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=62 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Serogroup A	83.3 Percentage of participants Interval 70.7 to 92.1
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Serogroup C	98.3 Percentage of participants Interval 91.1 to 100.0
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Serogroup Y	98.3 Percentage of participants Interval 90.8 to 100.0
Percentage of Participants With Vaccine Seroresponse by Serum Bactericidal Antibody Assay Using Baby Rabbit Complement Serogroup W	100 Percentage of participants Interval 94.2 to 100.0

PRIMARY outcome

Timeframe: Day 1 (pre-vaccination) and Day 31 (30 days post-vaccination on Day 1)

Population: The PPAS was a subset of the FAS. The FAS included participants who received the study vaccine and had a valid post-vaccination serology result. Only participants with data collected for each specified serogroup are reported.

Geometric Mean Concentrations (GMCs) of anti-tetanus toxoid antibodies was measured by diphtheria, tetanus, pertussis multiplexed electrochemiluminescent assay.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=65 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Geometric Mean Concentrations (GMCs) of Antibodies Against Tetanus Toxoid Day 1	0.642 International units/milliliter Interval 0.482 to 0.854
Geometric Mean Concentrations (GMCs) of Antibodies Against Tetanus Toxoid Day 31	8.56 International units/milliliter Interval 6.17 to 11.9

PRIMARY outcome

Timeframe: Up to 30 minutes post-vaccination on Day 1

Population: The SafAS included participants who received 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.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=69 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Number of Participants With Immediate Unsolicited Systemic Adverse Events (AEs)	0 Participants

PRIMARY outcome

Timeframe: Up to 7 days post-vaccination on Day 1

Population: The SafAS included participants who received the study vaccine.

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. Solicited injection site reactions included injection site tenderness, injection site erythema and injection site swelling. Solicited systemic reactions included fever, vomiting, crying abnormal, drowsiness, appetite loss and irritability.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=69 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Number of Participants With Solicited Injection Site Reactions and Systemic Reactions Solicited injection site reaction	24 Participants
Number of Participants With Solicited Injection Site Reactions and Systemic Reactions Solicited systemic reaction	35 Participants

PRIMARY outcome

Timeframe: Up to 30 days post-vaccination on Day 1

Population: The SafAS included participants who received 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/or onset window post-vaccination.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=69 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Number of Participants With Unsolicited Adverse Events	23 Participants

PRIMARY outcome

Timeframe: From vaccination (Day 1) up to 30 days post vaccination, 31 days

Population: The SafAS included participants who received 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 an important medical event. An AESI (serious or non-serious) was defined as one of scientific and medical concern specific to the Sponsor's study intervention or program, for which ongoing monitoring and rapid communication by the investigator to the Sponsor could be appropriate.

Outcome measures

Measure	MenACYW Conjugate Vaccine n=69 Participants Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Number of Participants With Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) SAEs	1 Participants
Number of Participants With Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs) AESIs	1 Participants

Adverse Events

MenACYW Conjugate Vaccine

Serious events: 1 serious events

Other events: 45 other events

Deaths: 0 deaths

Serious adverse events

Measure	MenACYW Conjugate Vaccine n=69 participants at risk Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Nervous system disorders Febrile Convulsion	1.4% 1/69 • Number of events 1 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.

Other adverse events

Measure	MenACYW Conjugate Vaccine n=69 participants at risk Participants who had received at least 1 of 2 priming doses of either Nimenrix® or Menveo® vaccine during infancy as part of their routine immunization before 12 months of age received a single booster dose (0.5 mL) of MenACYW conjugate vaccine as an IM injection at Day 1.
Infections and infestations Nasopharyngitis	5.8% 4/69 • Number of events 4 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
Metabolism and nutrition disorders Decreased Appetite	20.3% 14/69 • Number of events 14 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
Psychiatric disorders Irritability	31.9% 22/69 • Number of events 22 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
Nervous system disorders Somnolence	18.8% 13/69 • Number of events 13 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
Gastrointestinal disorders Diarrhoea	7.2% 5/69 • Number of events 5 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
Gastrointestinal disorders Vomiting	18.8% 13/69 • Number of events 13 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
General disorders Crying	20.3% 14/69 • Number of events 14 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
General disorders Injection Site Erythema	5.8% 4/69 • Number of events 4 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
General disorders Injection Site Pain	30.4% 21/69 • Number of events 21 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
General disorders Injection Site Swelling	5.8% 4/69 • Number of events 4 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.
General disorders Pyrexia	20.3% 14/69 • Number of events 15 • AEs, SAEs and all-cause mortality (deaths) were collected from vaccination (Day 1) up to 30 days post vaccination, 31 days. Analysis was performed on SafAS.

Additional Information

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Results disclosure agreements

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Restriction type: OTHER