This trial evaluated the use of a tetravalent vaccine against dengue.

Primary objectives:

• To describe the humoral immune response to dengue before and after each vaccination with tetravalent dengue vaccine in adults, adolescents, and children.
• To evaluate the safety of each vaccination with tetravalent dengue vaccine in the 4 age cohorts.
• To evaluate the persistence of antibodies against dengue during 5 years after the first vaccination with tetravalent dengue vaccine in the 4 age cohorts.

Safety assessments included solicited reactions within 7 or 14 days after each injection, unsolicited adverse events within 28 days after each injection, and serious adverse events during the study period.

Inclusion Criteria :

• Aged 2 to 45 years on the day of inclusion.
• Provision of Informed Consent/Assent Form signed by the participant (and/or by the parent or another legally acceptable representative for participants <18 years).
• Participant (and parent/guardian for participants <18 years) able to attend all scheduled visits and to comply with all trial procedures.
• For a female participant of child-bearing potential, avoid becoming pregnant (use of an effective method of contraception or abstinence) for at least 4 weeks prior to the first vaccination, until at least 4 weeks after the last vaccination.
• Participant in good health, based on medical history, physical examination and laboratory parameters.

Exclusion Criteria :

• Personal or family history of thymic pathology (thymoma), thymectomy, or myasthenia.
• For a female participant of child-bearing potential, known pregnancy or positive serum pregnancy test at Screening.
• For a female participant of child-bearing potential, known pregnancy or positive urine pregnancy test on the day of the first injection.
• Breast-feeding female participant.
• Receipt of any vaccine in the 4 weeks preceding the first trial vaccination.
• Human immunodeficiency virus, hepatitis B, or hepatitis C seropositivity in the blood sample taken at screening.
• Planned participation in another clinical trial during the first year of the study.
• Known or suspected congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the past 6 months, or long-term systemic corticosteroids therapy.
• Known systemic hypersensitivity to any of the vaccine components or history of a life-threatening reaction to the trial vaccines or to a vaccine containing any of the same substances.
• Chronic illness at a stage that could interfere with trial conduct or completion, in the opinion of the Investigator.
• Current alcohol abuse or drug addiction that may interfere with the participant's ability to comply with trial procedures.
• Receipt of blood or blood-derived products in the past 3 months that might interfere with the assessment of immune response.
• Participant deprived of freedom by an administrative or court order, or in an emergency setting, or hospitalized without his/her consent.
• Laboratory abnormalities of at least moderate severity or clinically significant according to the Investigator in blood sample taken at screening.
• Participation in another clinical trial investigating a vaccine, drug, medical device, or a medical procedure in the 4 weeks preceding the first trial vaccination.
• Planned receipt of any vaccine in the 4 weeks following the first trial vaccination.
• Familial atopy medical history (parents, brothers, or sisters).
• Previous vaccination with meningococcal A+C or typhoid vaccines within 3 years prior to inclusion.
• History of meningococcal or typhoid infections (confirmed either clinically, serologically or microbiologically).

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

The safety analysis set was defined as participants who received at least 1 dose of CYD dengue vaccine or control vaccine.

Serious Adverse Events (SAEs) data were collected throughout the study from Day 0 to Year 4, and non-serious Adverse Events were collected for 28 days after each injection.

Non-related SAEs were collected from Day 0 (post-injection) up to 6 months after the last injection. Related and fatal SAEs were reported from 6 months until the end of study (up to 4 years).

None reported.

The first and second vaccinations were administered in a blind-observer manner. The third vaccination was planned to be administered in a single-blind manner; however, due to the cancellation of the statistical analysis after the second vaccination, the third vaccination was also administered in a blind- observer manner. To ensure the blind-observer design of the 3 vaccinations, the product was prepared in a separate room whether neither the Investigator nor participant had access.