Efficacy, Safety and Immunogenicity of Takeda's Tetravalent Dengue Vaccine (TDV) in Healthy Children

Inclusion Criteria

• Is aged 4 to 16 years, inclusive, at the time of randomization.
• Is in good health at the time of entry into the trial as determined by medical history, physical examination (including vital signs) and clinical judgment of the Investigator.
• The participant and/or the participant's parent/guardian signs and dates an assent/written informed consent form where applicable, and any required privacy authorization prior to the initiation of any trial procedures, after the nature of the trial has been explained according to local regulatory requirements.
• Can comply with trial procedures and are available for the duration of follow-up.

Inclusion criteria for Booster Phase:

• Is included in the per-protocol set (PPS) of the trial.
• Was aged 4 to 11 years at the time of randomization in the study (Day 1 [Month 0]).

Exclusion Criteria

• Has febrile illness (temperature ≥38°C) or moderate or severe acute illness or infection at the time of randomization.
• Has history of or any illness that, in the opinion of the Investigator, might interfere with the results of the trial or pose an additional risk to the participant due to participation in the trial.
• Has received any other vaccine within 14 days (for inactivated vaccines) or 28 days (for live vaccines) prior to Day 1 (Month 0) or planning to receive any vaccine within 28 days after Day 1 (Month 0).
• Has participated in any clinical trial with another investigational product 30 days prior to Day 1 (Month 0) or intent to participate in another clinical trial at any time during the conduct of this trial.
• Has previously participated in any clinical trial of a dengue candidate vaccine, or previous receipt of a dengue vaccine.
• Is first degree relative of individuals involved in trial conduct.
• Females of childbearing potential who are sexually active, and who have not used any of the acceptable contraceptive methods for at least 2 months prior to Day 1 (Month 0).
• Females of childbearing potential who are sexually active, and who refuse to use an acceptable contraceptive method up to 6 weeks post-second vaccination.
• Deprived of freedom by administrative or court order, or in an emergency setting, or hospitalized involuntarily.
• Current alcohol abuse or drug addiction that may interfere with the participant's ability to comply with trial procedures.
• Identified as an employee of the Investigator or trial center, with direct involvement in the proposed trial or other trials under the direction of that Investigator or trial center.

Exclusion criteria for Booster Phase:

• Receipt of any other vaccine within 14 days (for inactivated vaccines) or 28 days (for live vaccines) prior to Day 1b (Month 0b), or planning to receive any vaccine within 28 days after Day 1b (Month 0b).
• Participation in any clinical trial with another investigational product at any time during participation in this trial or intent to participate in another clinical trial at any time during the conduct of the booster phase of this trial.