A Phase IIb, Randomized, Observer-Blind Study to Describe the Safety, Tolerability, and Immunogenicity of MenABCWY Administered on Different Dosing Schedules in Healthy Adolescents

• Participants or/and participants' parent(s)/Legally Acceptable Representative(s) \[LAR(s)\] who, in the opinion of the investigator, can and will comply, with the requirements of the protocol.

• Written or witnessed/thumb printed informed consent obtained from the participant/parent(s)/LAR(s) of the participant prior to performance of any study specific procedure.

• Written informed assent obtained from the participant (if applicable) prior to performing any study specific procedure.

• A male or female between, and including, 11 and 14 years of age (i.e. 14 years + 364 days) at the time of the first vaccination.

• Healthy participants as established by medical history, physical examination and clinical judgment of the investigator before entering into the study.

• Female participants of non-childbearing potential may be enrolled in the study. Non-childbearing potential is defined as pre-menarche, hysterectomy, bilateral-salpingectomy or bilateral ovariectomy.

• Female participants of childbearing potential may be enrolled in the study, if the participant:

‣ has practiced adequate contraception for 30 days prior to first vaccination, and

⁃ has a negative pregnancy test\* on the day of vaccination, and

⁃ has agreed to follow adequate contraception for 30 days before each of the 2 subsequent vaccinations and for 30 days after each vaccination \* Urine samples for pregnancy testing will be collected from female participants of childbearing potential at Visit 1, Visit 3 and Visit 5 prior to the vaccination.