Subjects reporting SAEs from day 1 to visit 6 (at 24 months of age) were assessed. A serious adverse event (SAE) is defined as any untoward medical occurrence that at any dose results in one or more of the following: death, is life-threatening, required or prolonged hospitalization, persistent or significant disability/incapacity, congenital anomaly/or birth defect, An important and significant medical event that may not be immediately life threatening or resulting in death or hospitalization but, based upon appropriate medical judgment, may jeopardize the subject or may require intervention to prevent one of the other outcomes listed above.

To assess antibody persistence against N. meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using human serum complement.

To assess antibody persistence against N. Meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement

To assess antibody persistence against N. Meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement

To assess antibody response against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement.

To assess antibody response against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement.

To assess persistence of antibody response in terms of GMTs using hSBA assay against N. meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

To assess persistence of antibody response in terms of GMTs using rSBA assay against N. meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

To assess antibody response in terms of GMTs using hSBA assay against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

To assess antibody response in terms of GMTs using rSBA assay against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

Solicited local AEs reported from day 1 to day 7 after each vaccination were assessed. Assessed local symptoms include injection site erythema, injection site induration and injection site tenderness. Any = incidence of a particular symptom regardless of intensity grade.Threshold for Erythema and Induration: Type II None (<10 mm), Any (>=10 mm)

Analysis was performed on the solicited safety set, which included all subjects who received a study vaccination and reported any solicited adverse event data and/or indicators of solicited adverse events.

Solicited systemic AEs reported from day 1 to day 7 after each vaccination were assessed. Assessed systemic symptoms include change in eating habits, sleepiness, irritability, vomiting, diarrhea and fever (body temperature ≥ 38°C (100.4°F)).

Analysis was performed on the solicited safety set, which included all subjects who received a study vaccination and reported any solicited adverse event data and/or indicators of solicited adverse events.

An unsolicited adverse event is an adverse event that was not solicited using a Subject Diary and that was spontaneously communicated by a subject parent(s)/legal guardian(s)] who has signed the informed consent. All medically attended unsolicited AEs were collected from Day 1 to Visit 6.

Analysis was performed on the unsolicited safety set, which included all subjects who received a study vaccination and reported any unsolicited adverse event data.

Subjects reporting SAEs from day 1 to visit 6 (at 24 months of age) were assessed. A serious adverse event (SAE) is defined as any untoward medical occurrence that at any dose results in one or more of the following: death, is life-threatening, required or prolonged hospitalization, persistent or significant disability/incapacity, congenital anomaly/or birth defect, An important and significant medical event that may not be immediately life threatening or resulting in death or hospitalization but, based upon appropriate medical judgment, may jeopardize the subject or may require intervention to prevent one of the other outcomes listed above.

Analysis was performed on the overall safety set, which included all subjects who received a study vaccination and reported any solicited/unsolicited adverse event data.

To assess antibody persistence against N. meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using human serum complement.

Analysis was performed on the Full analysis set (FAS), which included all enrolled subjects who received at least one study vaccination and provided an evaluable hSBA Visit 6 assessment, one year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age), for at least one serogroup.

To assess antibody persistence against N. Meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement

Analysis was performed on the FAS, which included all enrolled subjects who receive at least one study vaccination and provided an evaluable rSBA Visit 6 assessment, one year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age), for at least one serogroup.

To assess antibody persistence against N. Meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement

Analysis was performed on the FAS, which included all enrolled subjects who receive at least one study vaccination and provided an evaluable rSBA Visit 6 assessment, one year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age), for at least one serogroup.

To assess antibody response against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using human serum complement.

The Analysis was done on FAS hSBA 1 month, which included all enrolled subjects who received at least one study vaccination and who provided evaluable hSBA immunogenicity data at 1 month after last vaccination for at least one serogroup.

To assess antibody response against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement.

The Analysis was done on FAS rSBA 1 month, which included all enrolled subjects who received atleast one study vaccination and who provided evaluable rSBA immunogenicity data at 1 month after last vaccination for atleast one serogroup.

To assess antibody response against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine as measured by serum bactericidal assay using rabbit serum complement.

The Analysis was done on FAS rSBA 1 month, which included all enrolled subjects who received atleast one study vaccination and who provided evaluable rSBA immunogenicity data at 1 month after last vaccination for atleast one serogroup.

To assess persistence of antibody response in terms of GMTs using hSBA assay against N. meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

Analysis was performed on the Full analysis set (FAS), which included all enrolled subjects who received atleast one study vaccination and provided an evaluable hSBA Visit 6 assessment, one year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age ), for atleast one serogroup.

To assess persistence of antibody response in terms of GMTs using rSBA assay against N. meningitidis serogroups A, C, W and Y at 1 year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

Analysis was performed on the Full analysis set (FAS), which included all enrolled subjects who received atleast one study vaccination and provided an evaluable rSBA Visit 6 assessment, one year after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age ), for atleast one serogroup.

To assess antibody response in terms of GMTs using hSBA assay against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

The Analysis was done on FAS hSBA 1 month, which included all enrolled subjects who received atleast one study vaccination and provided evaluable hSBA immunogenicity data at 1 month after last vaccination for atleast one serogroup.

To assess antibody response in terms of GMTs using rSBA assay against N. meningitidis serogroups A, C, W and Y at 1 month after completion of a 4-dose infant vaccination series (2, 4, 6 and 12 months of age) of MenACWY vaccine.

The Analysis was done on FAS rSBA 1 month, which included all enrolled subjects who received atleast one study vaccination and provided evaluable rSBA immunogenicity data at 1 month after last vaccination for atleast one serogroup.