The purpose of this study is to assess the cellular immune responses following 2 doses given 3 months apart of tetravalent dengue vaccine candidate (TDV) in 4 to 16 years' healthy participants.
The vaccine tested in this study was TDV. This study assessed cellular immune responses and safety up to 3 years post second TDV administration to healthy children aged 4 to 16 years and in dengue endemic regions. The study enrolled 200 participants. Participants received: • TDV 0.5 mL subcutaneous (SC) injection into the upper arm at Day 1 (Month 0) and at Day 90 (Month 3). This multi-center trial was conducted in Panama and Philippines. 198 participants received the 2-dose schedule of TDV, and 2 participants received only the first dose of TDV (Day 1). Participants made multiple visits to the clinic and were contacted at least every week for the entire study duration post first injection.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
200
TDV SC injection.
CEVAXIN
Panama City, Panama
Research Institute for Tropical Medicine
City of Muntinlupa, Philippines
Percentage of Participants With Cellular Immune Response to 2 Doses of Tetravalent Dengue Vaccine (TDV) at 1 Month Post Second Vaccination
Percentage of participants with cellular immune response were reported. Cellular immune response was defined as an interferon-gamma (IFN-γ) enzyme-linked immunospot (ELISPOT) response that was \>3 times higher compared to Baseline (Day 1) and ≥ 5 spots per well. Cellular immune response to any peptide pool was reported. The peptide pool included non-structural proteins (NS) NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. Percentage of participants with cellular immune response were reported. Percentages are rounded off to the nearest decimal point.
Time frame: 1 month post second vaccination (Day 120)
Magnitude of Cellular Immune Response Assessed by Number of Spot Forming Cells (SFC)/Million Peripheral Blood Mononuclear Cells (PBMCs) Measured by IFN-γ ELISPOT at 1 Month Post Second Vaccination
The magnitude of cellular immune response was assessed by the number of SFC/million PBMCs for participants with a cellular immune response. Cellular immune response was defined as IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1) and ≥ 5 spots per well. Data (SFC/million PBMC) for participants with a cellular immune response to any peptide pool is reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2.
Time frame: 1 month post second vaccination (Day 120)
Percentage of Participants With Cellular Immune Response to TDV at 1 Month Post First Vaccination, Pre-second Vaccination, 6 Months Post Second Vaccination, and Annually at Years 1, 2, and 3
Percentage of participants with cellular immune response were reported. Cellular immune response was defined as an IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1 \[M0\]) and \>=5 spots per well. Cellular immune response to any peptide pool was reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. Percentages are rounded off to the nearest decimal point.
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Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 6 months post second vaccination (Day 270); Years 1, 2 and 3
Magnitude of Cellular Immune Response Assessed by Number of SFC/Million PBMCs Measured by IFN-γ ELISPOT at 1 Month Post First Vaccination, Pre-second Vaccination, 6 Months Post Second Vaccination, and Annually at Years 1, 2, and 3
The magnitude of cellular immune response was assessed by the number of SFC/million PBMCs for participants with a cellular immune response. Cellular immune response was defined as IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1) and ≥ 5 spots per well. Data (SFC/million PBMC) for participants with a cellular immune response to any peptide pool is reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2.
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 6 months post second vaccination (Days 120 and 270); Years 1, 2 and 3
Percentage of Participants With Cellular Immune Responses to TDV at 1 Month Post First Vaccination, Pre-second Vaccination, 1 and 6 Months Post Second Vaccination, and Annually at Years 1, 2, and 3 Assessed by Country
Percentage of participants with cellular immune response by country were reported. Cellular immune response was defined as an IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1 \[M0\]) and \>=5 spots per well. Cellular immune response to any peptide pool was reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. Data is reported as per enrollment by country (Panama and Philippines). Percentages are rounded off to the nearest decimal point.
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90) 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, 3
Percentage of Participants With Cellular Immune Responses to TDV:1 Month Post First Vaccination, Pre-second Vaccination, 1 and 6 Months Post Second Vaccination, and Annually at Years 1, 2, and 3, by Dengue Baseline Seropositivity Status
Percentage of participants with cellular immune response by dengue Baseline seropositivity status were reported. Cellular immune response was defined as an IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1 \[M0\]) and \>=5 spots per well. Seropositive at Baseline was defined as a reciprocal neutralizing titer \>=10 for one or more dengue serotypes. Seronegative at Baseline was defined as having a reciprocal neutralizing titer \<10 for all dengue serotypes. The 4 dengue virus serotypes were dengue virus (DENV)-1, DENV-2, DENV-3 and DENV-4. Cellular immune response to any peptide pool was reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. Data is reported per Baseline seropositivity status of participants (Seropositive and Seronegative). Percentages are rounded off to the nearest decimal point.
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, and 3
Magnitude of Cellular Immune Response Assessed by Number of SFC/Million PBMCs Measured by IFN-γ ELISPOT at 1 Month Post First, Pre- Second Vaccination, 1 and 6 Months Post Second Vaccination, and Annually at Years 1, 2, and 3 by Country
The magnitude of cellular immune response by country was assessed by the number of SFC/million PBMCs for participants with a cellular immune response. Cellular immune response was defined as IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1) and ≥ 5 spots per well. Data (SFC/million PBMC) for participants with a cellular immune response to any peptide pool is reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. Data is reported as per enrollment by country (Panama and Philippines).
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, and 3
Magnitude of Cellular Immune Response Assessed by Number of SFC/Million PBMCs Measured by IFN-γ ELISPOT 1Month Post First Vaccination,Pre-second Vaccination;1,6Months Post Second Vaccination, Annually at Years1,2,3 by Dengue Baseline Seropositivity Status
The magnitude of cellular immune response by dengue Baseline seropositivity status was assessed by the number of SFC/million PBMCs for participants with a cellular immune response. Cellular immune response was defined as IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1) and ≥ 5 spots per well. Seropositive at Baseline was defined as a reciprocal neutralizing titer \>=10 for one or more dengue serotypes. Seronegative at Baseline was defined as having a reciprocal neutralizing titer \<10 for all dengue serotypes. The 4 dengue virus serotypes were dengue virus (DENV)-1, DENV-2, DENV-3 and DENV-4. Cellular immune response to any peptide pool was reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. Data is reported per Baseline seropositivity status of participants (Seropositive and Seronegative).
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, and 3
Percentage of Participants With Cellular Immune Response to TDV in Participants >10 Years of Age
Percentage of participants with cellular immune response in participants \>10 years of age were reported. Cellular immune response was defined as an IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1 \[M0\]) and \>=5 spots per well. Cellular immune response to any peptide pool was reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2.
Time frame: Day 14
Magnitude of Cellular Immune Response Assessed by Number of SFC/Million PBMCs Measured by IFN-γ ELISPOT in Participants >10 Years of Age
The magnitude of cellular immune response was assessed by the number of SFC/million PBMCs for participants with a cellular immune response. Cellular immune response was defined as IFN-γ ELISPOT response that was \>3 times higher compared to Baseline (Day 1) and ≥ 5 spots per well. Cellular immune response to any peptide pool was reported. The peptide pool included NS3 and NS5 for each of the dengue serotype: DENV-1, DENV-2, DENV-3 and DENV-4 and NS1 for DENV-2. SFC/million PBMC for any peptide pool is reported in participants \>10 years of age.
Time frame: Day 14
Phenotype Characterization of Cellular Immune Response Assessed by Percentage of Total T Cells of Cellular Response to DENV-2 NS Peptides at 1Month Post First Vaccination,Pre-second Vaccination;1,6Months Post Second Vaccination, Annually at Years1,2,3
The phenotype characterization of cellular immune response was assessed by intracellular cytokine staining (ICS) by the frequency of total cluster of differentiation 4 (CD4)+ and CD8+ T cells and was performed in a subset of participants with IFN- γ ELISPOT responses \>500 SFC/million cells and availability of sufficient cells. The peptide pools included NS1, NS3 and NS5 for DENV-2 serotype. Data are presented for the different expression profiles of interferon-gamma (IFN-γ), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-α) cytokines for each peptide pool. Data is reported based on the type of T cells present in participants at the time of analysis (CD4+ T cells and CD8+ T cells).
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, and 3
Phenotype Characterization of Cellular Immune Response Assessed by Percentage of Total T Cells of Cellular Response DENV-2 NS Peptides,1Month Post First Vaccination,Pre Second Vaccination;1,6Months Post Second Vaccination,Annually at Years1,2,3 by Country
The phenotype characterization of cellular immune response by country was assessed by ICS by the frequency of total CD4+ and CD8+ T cells and was performed in a subset of participants with IFN- γ ELISPOT responses \>500 SFC/million cells and availability of sufficient cells. The peptide pools included NS1, NS3 and NS5 for DENV-2 serotype. Data are presented for the different expression profiles of IFN-γ, IL-2 and TNF-α cytokines for each peptide pool. Data is reported per country (Panama and Philippines) based on the type of T cells present in participants at the time of analysis (CD4+ T cells and CD8+ T cells).
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, and 3
Phenotype Characterization of Cellular Immune Response by Percentage of Total T Cells DENV-2 NS Peptides at 1Month Post First Vaccination,Pre Second Vaccination;1,6Months Post Second Vaccination,Annually at Years1,2,3 by Dengue Baseline Seropositivity
The phenotype characterization of cellular immune response by dengue Baseline seropositivity status was assessed by the frequency of total CD4+ and CD8+ T cells and was performed in a subset of participants with IFN- γ ELISPOT responses \>500 SFC/million cells and availability of sufficient cells. Seropositive was defined as a reciprocal neutralizing titer (MNT50) \>=10 for one or more dengue serotypes. Seronegative was defined as titer value of \<10 for all 4 serotypes. The peptide pools included NS1, NS3 and NS5 for DENV-2 serotype. Data are presented for the different expression profiles of IFN-γ, IL-2 and TNF-α cytokines for each peptide pool. Data is reported per Baseline seropositivity status (Seropositive and Seronegative) based on the type of T cells present in participants at the time of analysis (CD4+ T cells and CD8+ T cells).
Time frame: 1 month post first vaccination (Day 30); pre-second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); Years 1, 2, and 3
Geometric Mean Titers (GMT) of Neutralizing Antibodies for Each of the 4 Dengue Serotypes at 1 Month Post First Vaccination, Pre Second Vaccination, and 1, 6 Months Post Second Vaccination and Then Annually Up to 3 Years
GMT of neutralizing antibodies was measured by microneutralization test (MTN). The dengue virus serotypes are DENV-1, DENV-2, DENV-3 and DENV-4.
Time frame: 1 month post first vaccination (Day 30); pre second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); annually up to 3 years (Years 1, 2 and 3)
Percentage of Participants Seropositive for Each of the 4 Dengue Serotypes at 1 Month Post First Vaccination, Pre-second Vaccination, and 1, 6 Months Post Second Vaccination and Then Annually up to 3 Years
Seropositive was defined as a reciprocal neutralizing titer ≥10. The dengue virus serotypes are DENV-1, DENV-2, DENV-3 and DENV-4.
Time frame: 1 month post first vaccination (Day 30); pre second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); annually up to 3 years (Years 1, 2 and 3)
Percentage of Participants Seropositive for Multiple Dengue Serotypes at 1 Month Post First Vaccination, Pre Second Vaccination, 1, 6 Months Post Second Vaccination and Annually up to 3 Years
Seropositive was defined as a reciprocal neutralizing titer ≥10. The dengue virus serotypes are DENV-1, DENV-2, DENV-3 and DENV-4. Seropositive for multiple dengue serotypes were summarized in the following categories: tetravalent and at least trivalent.
Time frame: 1 month post first vaccination (Day 30); pre second vaccination (Day 90); 1 and 6 months post second vaccination (Days 120 and 270); annually up to 3 years (Years 1, 2 and 3)
Percentage of Participants Experiencing Unsolicited Adverse Events (AE)
An AE was defined as any untoward medical occurrence in a clinical investigation participant administered a trial vaccine; it does not necessarily have to have a causal relationship with trial vaccine administration.
Time frame: Up to 28 days (day of vaccination + 27 days) after administration of each vaccine dose on Day 1 [Month 0] and Day 90 [Month 3]
Percentage of Participants With Medically Attended AEs (MAAEs)
MAAEs were defined as AEs leading to a medical visit to or by a healthcare professional, including visits to an emergency department, but not fulfilling seriousness criteria.
Time frame: From first vaccination (Day 1) up to 6 months post second vaccination (Day 270)
Percentage of Participants With Serious Adverse Events (SAEs)
A SAE was defined as any untoward medical occurrence or effect that at any dose results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability / incapacity, is a congenital anomaly / birth defect or is medically important due to other reasons than the above mentioned criteria.
Time frame: From first vaccination (Day 1) up to end of study (Approximately 3 years)
Percentage of Participants With Virologically Confirmed Dengue
Participants with febrile illness defined as fever ≥38°C on any 2 of 3 consecutive days were evaluated for dengue. Virologically confirmed dengue was defined as febrile illness with a positive serotype-specific RT-PCR (i.e. positive dengue detection RT-PCR).
Time frame: From first vaccination (Day 1) up to 6 months post second vaccination (Day 270)