SHAN6

This open label randomized study will be conducted to evaluate and/or describe the immunogenicity and describe the safety of MenACYW conjugate vaccine when administered in infants and toddlers.
It will be conducted in India and the RSA in 2 cohorts:
* Cohort I: Infants and toddlers 6 months to 16 months of age (Cohort I)
* Cohort II: Infants and toddlers 6 weeks to 15 months of age (Cohort II) In Cohort I, eligible participants will be randomized in a 1:1 ratio to receive 2 intramuscular (IM) injections (1+1 vaccination schedule) of either MenACYW conjugate vaccine (Groups 1 and 3) or Menactra vaccine (Groups 2 and 4), co-administered with routine pediatric vaccines.
In Cohort II, eligible participants will be randomized in a 2:1 ratio to receive either 3 IM injections (2+1 vaccination schedule) of MenACYW conjugate vaccine co-administered with routine pediatric vaccines (Groups 5 and 7) or routine pediatric vaccines only (Groups 6 and 8).
The primary objectives of this study are:
* To demonstrate the non-inferiority of immunogenicity of 2 doses of MenACYW conjugate vaccine compared to 2 doses of Menactra® vaccine in infants and toddlers 6 months to 16 months of age (Cohort I) in terms of serum bactericidal assay using human complement (hSBA) seroprotection (titers ≥ 1:8) in India and the Republic of South Africa (RSA)
* To demonstrate the vaccine immune sufficiency of 3 doses of MenACYW conjugate vaccine in infants and toddlers 6 weeks to 15 months of age (Cohort II) in terms of hSBA seroprotection (titers ≥ 1:8) in India and the RSA
The secondary objectives of this study are:
* To describe the antibody titers to the meningococcal serogroups A, C, Y, and W:
* before and 30 days post primary series of MenACYW conjugate vaccine and before and 30 days post booster dose of MenACYW conjugate vaccine in infants and toddlers 6 weeks to 15 months of age (Cohort II) in India and the RSA when administered concomitantly with other age-recommended vaccines.
* before and after 30 days post each dose of MenACYW conjugate vaccine or Menactra vaccine in infants and toddlers 6 months to 16 months of age (Cohort I) in India and the RSA when administered concomitantly with other age-recommended vaccines.
* To describe the antibody responses against the antigens of the other age-recommended vaccines when administered concomitantly with MenACYW conjugate vaccine:
* in infants and toddlers 6 weeks to 15 months of age (Cohort II) in India and the RSA.
* in infants and toddlers 6 months to 16 months of age (Cohort I) in India and the RSA.
* To describe the safety profile of MenACYW conjugate vaccine and that of licensed Menactra vaccine in infants and toddlers 6 months to 16 months of age (Cohort I) in India and the RSA when administered concomitantly with other age-recommended vaccines.
* To describe the safety profile of MenACYW conjugate vaccine in infants and toddlers 6 weeks to 15 months of age (Cohort II) in India and the RSA when administered concomitantly with other age-recommended vaccines.
* To describe the safety profile of age-recommended vaccines:
* in infants 6 weeks to 15 months of age (Cohort II) in India and the RSA when administered concomitantly with MenACYW conjugate vaccine.
* in infants and toddlers 6 months to 16 months of age (Cohort I) in India and the RSA when administered concomitantly with MenACYW conjugate vaccine.
The duration of each participant's active participation in the study will be approximately 10 to 11 months for Cohort I and 13,5 to 14,5 months for Cohort II.