A Study of SII Yellow Fever Vaccine to Compare Safety and Immunogenicity With STAMARIL® In Healthy Infants

The study is designed as a Phase III, double-blind, multi-center, randomized, active-controlled study in which four groups of participants (n=554 per group) will receive either one of three different manufacturing lots of SII-YFV or STAMARIL® - a licensed and WHO pre-qualified YFV.

The study is designed as a Phase III, double-blind, multi-center, randomized, active-controlled study in which four groups of participants (n=554 per group) will receive either one of three different manufacturing lots of SII-YFV or STAMARIL® - a licensed and WHO pre-qualified YFV.

A single dose of either SII-YFV or STAMARIL® will be administered concomitantly with an MMR and a Men A vaccine. The study will start only after the approval from the applicable ethics committees and national regulatory agencies. Following parental / guardian consent, participants will be screened for eligibility based on the defined inclusion and exclusion criteria for the trial. There will be three scheduled visits during the study. A screening and vaccination visit (Day 0) followed by additional study visits on Day 28 and on Day 180 post-vaccination.

Eligibility Criteria:
Inclusion Criteria:

1. Healthy infants as established by medical history and clinical examination
2. Male or female infants aged 9 to \< 12 months (from the day they reach 9 months-of-age until the day before they reach 12-months/1-year-of-age)
3. Parental/ guardian ability and willingness to provide informed consent (as per local requirements/procedures), and to adhere to the protocol requirements.
4. Intend to remain residing in the study area throughout study participation
5. Parents/guardians willing to avoid the use of traditional/herbal local medications and treatments in infants for the duration of the study

Exclusion Criteria:

1. Fever (\> 37.5°C) or any clinically significant acute infection at time of vaccination \[Temporary exclusion criteria - participants may be rescreened at least 48 hours after the last recorded fever\].
2. Previous history of laboratory confirmed infection with yellow fever, measles, mumps, rubella, Neisseria meningitidis serogroup A, and other flaviviruses e.g., dengue fever, tick-borne-encephalitis (TBE), Japanese encephalitis (JE), West Nile virus (WNV), zika virus, etc.

5. Previous vaccination against yellow fever, measles, mumps, rubella, Neisseria meningitidis serogroup A, TBE, JE, or dengue fever.

6. Receipt of any vaccine within past 28 days or planned vaccination until completion of day 28 study visit 7. A known hypersensitivity to any of the vaccine components (including gelatin, eggs, egg products, or chicken protein) or history of a life threatening reaction to any past vaccine 8. Receipt of immunoglobulin therapy and/or blood products since birth or planned administration until completion of Day 28 visit 9. Current or planned participation in another interventional study at any point throughout the entire study period 10. Receipt of any other investigational product or unlicensed medication in the preceding 28 days, or planned use until completion of Day 28 visit 7. Presence of significant malnutrition (weight-for-height z-score \< -3SD)