Study of a Novel Tetravalent Dengue Vaccine in Healthy Children and Adolescents Aged 9 to 16 Years in Latin America
Condition: Dengue Fever; Dengue Hemorrhagic Fever; Dengue
MeSH terms: Dengue; Hemorrhagic Fevers, Viral; Severe Dengue; Fever; Hyperthermia
Study type: Interventional
Phase: Phase 3

Summary: 
      The aim of the study was to assess the efficacy of Sanofi Pasteur's CYD dengue vaccine in
      preventing symptomatic virologically-confirmed dengue cases for dengue-endemic areas of Latin
      America.

      Primary Objective:

      To assess the efficacy of CYD dengue vaccine after 3 vaccinations at 0, 6, and 12 months in
      preventing symptomatic virologically-confirmed dengue (VCD) cases, regardless of the
      severity, due to any of the four serotypes in children and adolescents aged 9 to 16 years at
      the time of inclusion.

      Secondary Objectives:

        -  To describe the efficacy of CYD dengue vaccine in preventing symptomatic VCD cases after
           the third dose to the end of the Active Phase, after at least 1 dose, and after 2 doses.

        -  To describe the occurrence of hospitalized VCD cases and the occurrence of severe
           (clinically severe or as per World Health Organization (WHO) criteria) VCD cases,
           throughout the Surveillance Expansion Period (SEP) and throughout the trial (from Day 0
           until the end of the study).

        -  To describe the antibody response to each dengue serotype after Dose 2, after Dose 3,
           and 1 and 5 years after Dose 3.

        -  To describe the occurrence of serious adverse events (SAEs), including SAEs of special
           interest in all participants throughout the trial period.
    

Detailed description: 
      Participants were randomized to either receive 3 injections of CYD dengue vaccine or a
      placebo at 0, 6, and 12 months.

      A subset of participants from each country (N=2000) was also evaluated for reactogenicity and
      immunogenicity.

      For each participant, the Active Phase of dengue case detection began after the first
      injection (Dose 1) and continued until 13 months after the third injection (Dose 3). It was
      assumed that 12 months of surveillance should result in the detection of a sufficient number
      of VCD cases to allow for an assessment of efficacy.

      The Hospital Phase began after the Active Phase. Participants with a febrile illness and
      requiring hospitalization were screened for dengue until the end of the study.

      Participants who consented to participate in the SEP were actively followed for dengue case
      detection (i.e. at least weekly contact and capturing any acute febrile illness, not just
      hospitalized febrile cases, as in the Active Phase). The SEP was designed to maximize the
      detection of symptomatic VCD (hospitalized or not) in order to describe CYD dengue vaccine
      efficacy and safety in preventing symptomatic dengue in the long-term. Participants who
      declined participating in the SEP continued surveillance as in the Hospital Phase until trial
      completion.

      Symptomatic VCD cases occurring more than (>) 28 days after dose 3 (during the Active Phase)
      are defined as:

        -  Acute febrile illness (i.e. temperature >=38 degree Celsius (°C) on at least 2
           consecutive days)

        -  Virologically confirmed by dengue Reverse Transcriptase-Polymerase Chain Reaction
           (RT-PCR) and/or dengue non-structural (NS)1 enzyme-linked immunosorbent assay (ELISA) Ag
           test.

      Severity was assessed using a definition consistent with the 1997 WHO Classification Dengue
      Hemorrhagic Fever and by an independent Data Monitoring Committee (IDMC) severity criteria.
    

Intervention name(s): Live, attenuated, dengue serotype 1, 2, 3, 4 virus; Placebo: (NaCl) 0.9% solution
Intervention type(s): Biological; Biological
Intervention description(s): 0.5 mL, Subcutaneous; 0.5 mL, Subcutaneous
Other intervention name(s): CYD Dengue Vaccine
Intervention MeSH terms: Vaccines
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Dengue Virus; Dengue fever; Dengue Hemorrhagic Fever; CYD dengue vaccine; Flavivirus; Dengue Disease