Immunogenicity and Safety of a Quadrivalent Meningococcal Conjugate Vaccine in Infants and Toddlers When Administered Concomitantly With Routine Pediatric Vaccines in the United Kingdom

The primary objective of the study was to demonstrate the non-inferiority of the antibody responses to meningococcal serogroups A, C, W, and Y (MenACYW) in terms of serum bactericidal assay using human complement (hSBA) vaccine seroprotection (antibody titer greater than or equal to \[\>=\] 1:8) when MenACYW Conjugate vaccine was administered concomitantly with Bexsero® in the second year of life compared to when MenACYW Conjugate vaccine was given alone.

The secondary objectives were to compare the hSBA antibody response in terms of geometric mean titers (GMTs) against meningococcal serogroups A, C, W, and Y when MenACYW Conjugate vaccine was administered concomitantly with Bexsero® or when MenACYW Conjugate vaccine was given alone in the second year of life; to describe the hSBA and serum bactericidal assay using baby rabbit complement (rSBA) antibody responses against meningococcal serogroups A, C, W, and Y before and after the 1st dose of MenACYW Conjugate vaccine administered at 3 months of age, before and after the 2nd dose of MenACYW Conjugate vaccine administered at 12 to 13 months of age for Group 1 and Group 2; to describe the hSBA and rSBA antibody persistence against meningococcal serogroups A, C, W, and Y after the 1st dose of MenACYW Conjugate vaccine administered at 3 months of age for Group 1 and Group 2.

Study duration per participant was approximately 11 to 12 months.

Eligibility Criteria:
Inclusion Criteria:

* Aged \>= 56 to less than or equal to (\<=) 89 days on the day of the first study visit.
* Born at full term of pregnancy (\>= 37 weeks) and with a birth weight \>= 2.5 kilogram (kg) (or 5 lb and 8 oz).
* Informed consent form had 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 were able to attend all scheduled visits and to comply with all trial procedures.

Exclusion Criteria:

-- Participation at the time of study enrollment (or in the 4 weeks preceding the first trial vaccination) or planned participation during the present trial period in another clinical trial investigating a vaccine, drug, medical device, or medical procedure.

* Receipt of any vaccine in the 4 weeks preceding the first trial vaccination (at Visit 1) or planned receipt of any vaccine in the 4 weeks before and/or following any trial vaccination except for influenza vaccination, which may be received at a gap of at least 2 weeks before or 2 weeks after any study vaccines. This exception includes monovalent pandemic influenza vaccines and multivalent influenza vaccines.
* Previous vaccination against meningococcal disease with either the trial vaccine or another vaccine (i.e., mono- or polyvalent, polysaccharide, or conjugate meningococcal vaccine containing serogroups A, C, W, or Y; or meningococcal B serogroup-containing vaccine).
* Previous vaccination (before Visit 1) with any pneumococcal, diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b (Hib), poliovirus, and/or rotavirus vaccines. Receipt of BCG vaccine at birth was acceptable.
* Receipt of immune globulins, blood or blood-derived since birth.
* Known or suspected congenital or acquired immunodeficiency, including Severe Combined Immunodeficiency disorder (SCID); or receipt of immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy; or long-term systemic corticosteroid therapy (prednisone or equivalent for more than 2 consecutive weeks) since birth.
* History of any neurologic disorders, including any seizures and progressive neurologic disorders or encephalopathy.
* History of Neisseria meningitidis infection, confirmed either clinically, serologically, or microbiologically.
* History of diphtheria, tetanus, pertussis, poliomyelitis, Hib, hepatitis B, Streptococcus pneumoniae, and/or rotavirus infection or disease.
* At high risk for meningococcal infection during the trial (specifically, but not limited to, participants with persistent complement deficiency, with anatomic or functional asplenia, or participants travelling to countries with high endemic or epidemic disease).
* History of Guillain-Barré syndrome.
* Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccines used in the trial or to a vaccine containing any of the same substances including neomycin, kanamycin, polymyxin, formaldehyde, and latex.
* Hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency.
* History of intussusception or uncorrected congenital malformation of the gastrointestinal tract that would predispose to intussusception.
* Verbal report of thrombocytopenia, contraindicating intramuscular vaccination in the investigator's opinion.
* Bleeding disorder, or receipt of anticoagulants in the 3 weeks preceding inclusion, contraindicating intramuscular vaccination.
* Chronic illness that, in the opinion of the investigator, was at a stage where it might interfere with trial conduct or completion.
* Any condition which, in the opinion of the investigator, might interfere with the evaluation of the study objectives, including planning to leave the area of the study site before the end of the study.
* Moderate or severe acute illness/infection (according to investigator judgment), or febrile illness (temperature \>= 38.0°C), or diarrhea or vomiting on the day of vaccination. A prospective participant should not be included in the study until the condition had resolved or the febrile event has subsided.
* Identified as a natural or adopted child of the Investigator or employee with direct involvement in the proposed study.