Study of ChimeriVax™ Tetravalent Dengue Vaccine in Healthy Peruvian Children Aged 2 to 11 Years

Immunogenicity and Safety of ChimeriVax™ Tetravalent Dengue Vaccine in Healthy Children Aged 2 to 11 Years Previously Vaccinated Against Yellow Fever in Peru

The aim of the trial was to evaluate the use of a tetravalent vaccine, CYD dengue vaccine, against dengue disease.

Primary Objectives:

• To describe the humoral immune response to dengue before and after each vaccination with dengue vaccine in two age cohorts of children (6 to 11 years and 2 to 5 years) previously vaccinated with yellow fever (YF) vaccine.
• To evaluate the safety of each vaccination with dengue vaccine in two age cohorts of children (6 to 11 years and 2 to 5 years).
• To describe viremia after the first and second vaccinations with dengue vaccine in a subgroup of 130 randomized participants (100 participants in Dengue Vaccine Group and 30 participants in Control Group) in two age cohorts of children (6 to 11 years and 2 to 5 years).

Participants were randomized to receive either three injections of CYD dengue vaccine or two injections of placebo, and one injection of a pneumococcal polysaccharide vaccine (Pneumo23®) at 0, 6, and 12 months, respectively.

Inclusion Criteria :

• Aged 2 to 11 years on the day of inclusion.
• Participant in good health, based on medical history, physical examination and laboratory parameters.
• Provision of Assent Form signed by the participants (for participants >=8 years old) and Informed Consent Form signed by the parents or another legally acceptable representative (and by an independent witness for illiterate parent[s]).
• Participant and parents/legally acceptable representative able to attend all scheduled visits and to comply with all trial procedures.
• For a female participant of child-bearing potential (girls post-menarche), avoid becoming pregnant (use of an effective method of contraception or abstinence) for at least 4 weeks prior to first vaccination, until at least 4 weeks after the last vaccination.
• Documented receipt of yellow fever vaccine since at least one month before the first vaccination.

Exclusion Criteria :

• Personal or family history of thymic pathology (thymoma), thymectomy, or myasthenia.
• For a female participant of child-bearing potential (girls post-menarche), known pregnancy.
• For a female participant of child-bearing potential (girls post-menarche), known pregnancy or positive pregnancy test 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 participation in another clinical trial during the trial.
• Known or suspected congenital or acquired immunodeficiency, immunosuppressive therapy such as anti-cancer chemotherapy or radiation therapy within the preceding 6 months, or long-term systemic corticosteroids therapy.
• Known systemic hypersensitivity to any of the vaccines components or history of a life-threatening reaction to the trial vaccines or to a vaccine containing any of the same substances.
• Systemic hypersensitivity to YF vaccine or history of a life-threatening reaction to YF vaccine.
• Chronic illness at a stage that could interfere with trial conduct or completion, in the opinion of the Investigator.
• Current or past alcohol abuse or drug addiction that may interfere with the participant's ability to comply with trial procedures.
• Receipt of any blood or blood-derived products in the past 3 months, that might interfere with the assessment of immune response.
• Receipt of any vaccine in the 4 weeks preceding the first trial vaccination.
• Planned receipt of any vaccine in the 4 weeks following the first trial vaccination.
• Human Immunodeficiency Virus, hepatitis B antigen, or hepatitis C seropositivity in blood sample taken at Screening.
• Clinically significant laboratory abnormalities (as determined by the Investigator) in blood sample taken at Screening.
• Known previous vaccination with pneumococcal polysaccharide vaccine.